Uncle Rod's Astro Blog

Wow! A magazine just for users of Schmidt Cassegrain Telescopes? Is it for real? No, it ain’t for real. I made it up out of whole cloth the other morning. Could such a magazine come to be, though? Perhaps. SCT users are hungry for reliableinformation about their telescopes and ancillary systems. And they don’t always get that reliable information online, as a voyage through a certain popular amateur astronomy forum will quickly show.

There is so much to the SCT world these days, so many gadgets and add-ons (the Schmidt Cassegrain has become the PC of the telescope world), that it’s hard to keep up. So, I do think a magazine like the above actually could make it if done right. At least as an e-zine as opposed to a “real” print magazine. In fact, if I were ten or twenty years younger and had more wherewithal, I’d do it myself. But I am not and I don’t. If somebody wants to do SCT Magazine, though, I gift you with the idea, no strings attached. Have fun.

Until such a publication exists, however, you can at least read about your favorite telescope design here, on occasion anyhow. Yeah, as you probably know, I’ve sorta pulled away from CATs, being more of a refractor person now. But I still like Schmidt Cassegrains and want to and will keep my hand in.

Improved SCTs

This isn’t exactly news; Meade’s ACF telescopes and Celestron’s Edge telescopes have been with us for years. But people still want to know, “Which is better? Is either one really much better than a standard SCT?”

The Meade ACF

Meade’s Advanced Coma Free design hit the streets in 2006 in the form of the company’s “Advanced Ritchey Chretien” the RCX400. I’m not going to go back and cover all the old ground concerning the spurious R-C claims and the ensuing controversy and lawsuit. Google is your friend, and I wrote about the whole episode years ago. Bottom line? The RCX (and the ACF) have nothing to do with R-Cs. They are of a design that’s been known for many a year, the “aplantic SCT.”

Meade RCX

The main difference between the ACF and a standard SCT is the ACF’s non-spherical secondary mirror (contrary to what you may have heard, it is a parabola rather than a hyperbola). The net effect is a telescope that features reduced coma compared to a standard SCT, which has coma of the same magnitude, roughly, as an f/6 Newtonian. The practical effect is that stars approaching the edge of the ACF telescope’s field look like stars rather than little comets.

How well do these ACF telescopes perform? In my experience, very well. The field edge is noticeably better that that in a regular Meade or Celestron telescope. That’s not the whole story, though. The real news is how good Meade’s ACF optics seem to be at the moment. Naturally, I can’t vouch for every OTA coming out of their Mexican factory, but those I’ve tried have been outstanding. Particularly a couple of f/10 LX200 tubes.

“F/10? Aren’t all SCTs sold today f/10?” No. The original RCX was an f/8, and today you get f/8 OTAs on Meade’s top of the line LX600 and LX850 rigs. You can also purchase 8 – 16-inch f/8 OTAs without mounts. With an f/8 ACF SCT, you get a wider field and reduced coma without the need for a reducer/corrector. The f/8s also have a much improved focusing system that eliminates focus shift and features dual focusing speeds.

Celestron’s Edge

Despite the two companies now being owned by the Chinese (perhaps by the same Chinese company, Synta; it’s hard to work out the lineage of Mainland Chinese corporations), the Meade vs. Celestron SCT arms race continues. Not long after the RCX debuted, Celestron announced a new SCT design of their own that offered even more improvement.

The Edge’s draw is that in addition to reducing coma, it also flattens the SCT’s curved field. The stars at the field edge of an Edge really are close to perfect visually and photographically. This is not accomplished by a new optical design, per se, but by the addition of internal corrective optics mounted in the telescope’s baffle tube.

Edge 800

Other than the built-in correctors, the Edges are pretty much standard SCTs. The only change is a slightly different optical prescription that moves the focal plane farther out from the rear cell (helpful in some imaging setups). While the focuser is the same old flop/shift arrangement as ever, Celestron has added primary mirror locks to the OTA to eliminate problems with mirror flop during imaging—locks don’t help with focus shift. There are also vents on the rear cell to aid with cool-down, which is a good thing.

How are the Edges? I have the 8-inch version, the Edge 800, and, as I have said before, if ever the term “refractor like” could be applied to the images of an SCT, it is with the Edge. Optically the scope is just beautiful. The only slight downer? The Edge’s corrective optics require a specially designed and expensive reducer on the rear cell if you don’t want to image or observe at f/10.

Celestron’s reducer, which takes the f/10 scopes down to f/7, works well visually and photographically. Unfortunately, though, the reducers proved hard to design, expensive to produce, and had to be tailored to each aperture. There are reducer models for the C8, C11, and C14, but one has not appeared for the C9.25 and it doesn’t appear one ever will—probably not enough 9.25s are sold to make a reducer for them financially viable. Other companies, like Optec, are producing reducers for use when imaging with the Edges, but unlike the Celestron reducers, they cannot be used visually.

Which should you choose? The ACF or the Edge? I own an Edge and am quite content with it. However, I find the field edge of the ACF to, frankly, look every bit as good as that of the Edge to my aged eyes. The ACFs I’ve used have been impressive, and if I were to buy a new SCT, which doesn’t seem that likely at this juncture, it might well be a 10-inch f/8 ACF.

The deeper question is, "Should I get an improved SCT at all?" That depends on you and your agenda. While these telescopes produce fine images, are they worlds better than those of a standard SCT equipped with a reducer corrector? No. I recommend an improved SCT mainly for imagers using at least APS-C sized if not 35mm full frame sensors.

Mounts

Things have changed in SCT land. For nearly 30 years “SCT” equaled “fork mount.” That’s no longer the case, with many prospective SCT users refusing to consider the time-honored fork configuration, and instead drooling over sexy and expensive German equatorial mounts.

While it’s true GEMs have some advantages, especially when it comes to making large aperture CATs more manageable, the fork has its advantages too, like making imaging near the Meridian more practical. While the fork may not be sexy anymore, probably more SCTs are still sold in fork mount packages than as bare OTAs or GEM configurations (excepting the Celestron C14, which hasn’t been sold on a fork for many years).

The Meade LX600

Yes, the two manufacturers have continued to sell forks with wild abandon, but only Meade has offered anything new (well sorta) in this arena in recent times. That new fork is the LX600.

What makes the LX600 a prime choice for an SCT user wanting a fork mount scope? It’s not so much the excellent f/8 OTA, or even the StarLock system which handles pointing and guiding chores (and operates full time), it’s that somebody finally did something about the SCT weight problem.

One of my favorite SCTs of all time was my old fork-mount NexStar 11 GPS, Big Bertha. I used her happily for more than a decade, but recently I had to admit she was becoming just too much for me. Too heavythat is. Even when I was a decade younger, lifting her 68-pounds onto a tripod (or loading her into and out of a vehicle in her huge case) was a not inconsequential task. I could still do it at the time I removed the OTA from the fork and bought a CGEM to use as her mount two years ago, but I no longer wanted to—and hadn’t really wanted to in a long time. What good is a scope you don't want to use?

Do I like Bertha on a GEM? Yes, but. The fact is that the fork was more convenient and comfortable, especially for visual observing in alt-azimuth mode. If only she had been a little easier to set up and transport.

Years ago, Celestron’s enormous old fork mount C14s could be removed from their mounts. It wasn’t easy to do, but it could be done, and you didn’t have to remove hordes of screws to do so. It made setting up that huge scope at least somewhat easier, if not easy. I wondered for years why M&C didn’t revisit that idea for larger aperture SCTs.

Enter the Meade LX600. The tube can be removed and replaced on the fork with some ease. Not only does the tube come off the fork, so do the upper fork arms, which go into alignment pins on the lower fork assembly. I won’t try to tell you that that will make mounting the 12-inch and 14-inch scopes trivial, but it is easier. It’s the 10-inch that really benefits from this, set up. The removable OTA turns the scope into something at least doable for the broken down among us like your correspondent. Even with the removable OTA, trying to get the telescope set up in equatorial mode is not a safe job for one person, but it does make assembling the 10-inch in alt-azimuth fashion at least thinkable for a lone observer.

Celestron Evolution

EVO and friend...

When it comes to forks, most of Celestron’s recent releases have been incremental improvements. For example, their CPC Deluxe Edge scopes use a fork and drive base much like that of the standard CPCs, the successor to the NexStar GPS scopes. The only advance is that the Deluxe has (somewhat) improved gears and motors. Yep, I found the CPC Deluxe to be kinda ho-hum, but that didn’t mean Celestron didn’t have an interesting new fork idea up their sleeves: the Evolution.

The Evolution, available in 6, 8, and 9.25 inch apertures, at first glance doesn’t look much different from the light single arm-fork equipped NexStar SE. Like the NexStar SE, the Evolution mounts the tube to the fork using a Vixen compatible dovetail, making these small – medium aperture CATs quite portable indeed. That is not all there is to the “Evo” story, however.

The innovation here is that the Evolution comes with built-in wi-fi control. That’s right. You align and operate the telescope with your iOS or Android phone or tablet. The Evo comes with a hand control, but most users will never have to mess with it; they will prefer to run the Evo with their phones and SkySafari. I would guess the Evolution is the shape of things to come and that it won’t be long before the company’s larger fork mounts include wi-fi.

Which fork mount telescope would I choose if I were to buy one today? If I were wanting to do astrophotography, it would be, hands down, the LX600. That F/8 OTA and built in autoguiding system make a task that can often be daunting, imaging with a larger aperture SCT on a fork, much less frustrating. If I just wanted a portable CAT for looking, planetary imaging, and perhaps dabbling in deep sky photography, it would probably be the Evolution. Certainly, though, both companies’ older setups, particularly the Meade LX90, also deserve a look if you want a general use Schmidt Cassegrain.

Accessories

Where there are SCTs, there are accessories. Celestron and Meade still offer plenty of stuff to trick out your CAT, if not quite as much as they did in their salad days. What’s out there now? Focal reducers…GPS receivers…SCT style diagonals, yadda, yadda, yadda. None of it too inspiring. Well, with one exception, which happens to be from Celestron.

To be accurate, the Celestron StarSense alignment camera/system is not specifically an SCT product; it’s usable on most Celestron mounts, fork or GEM. Nevertheless, it’s often purchased for SCTs, and Celestron even offers some CAT configurations that include the StarSense in the package. Be that as it may, it’s one of the more impressive and useful add-ons it’s been my pleasure to try.

I first used the StarSense a couple of years ago. I was skeptical this little camera and replacement hand controller could really do as good a goto alignment as I could do manually. Frankly, I didn’t believe it would work at all.

I was completely wrong. Despite an early firmware release in the unit I tried, the goto alignment it produced was easily as good as what I could do myself, and it sure was a lot easier than centering up to six stars (or sometimes more) manually.

In the last couple of years, Celestron has cleaned up the firmware, and the StarSense is better than ever. One of the great benefits of it isn’t just the time/labor saving, but that it encourages astrophotographers to make best use of the Celestron All Star Polar Alignment Procedure (in the hand control).

To get the best polar alignment possible with ASPA, you really need to do two iterations of it. Unfortunately, you also need to redo the goto alignment after each ASPA. That means that when you are done you’ll have centered a total of 18 stars, not that much fun. StarSense takes away all that pain. It handles the alignments (in about 2 – 3 minutes each). All you have to do is center the ASPA star with the altitude and azimuth adjusters.

I also think StarSense has some untapped potential. Integrate it with a guidescope, and you’d have something like Meade’s excellent StarLock system. But one you could buy aftermarket and use with your Celestron scope.

Anyhow, that’s some of what’s happening on the current SCT scene. As new products and technologies arise, I promise to keep you updated, even if the telescopes I’m usually using out on the observing field are (choke!) refractors.

How do You Focus?

Well, you twitch the focus control until the image is sharp. That’s fine for visual observers, but attaining good focus for imaging can be and often needs to be a little more complicated. Your eyes can compensate for slightly out of focus images, even stars, when you’re observing visually, but slightly, just slightly, out of focus stars in images look absolutely dreadful. How can you ensure you are in dead-on focus?

There are various ways of achieving exact focus. More than a few camera control programs like Nebulosity have a fine focus routine that will get you there. You kinda need to get close to focus before those are effective, however, and I hate going out to the scope, twitching focus, going back to the computer, squinting at the images, and—well you get the idea. One way to achieve close focus quickly is with a Bahtinov mask.

What’s that? If you haven’t heard—they’ve been in use by imagers for some years now—it’s a plastic (usually) mask with slots cut in it. It fits over your objective, corrector, or the end of your reflector’s tube and produces a peculiar diffraction pattern on a star as seen here. You change focus until the two horizontal spikes are precisely centered between the diagonal spikes on each side. I find the Bahtinov sensitive enough that I usually don’t even have to worry with Nebulosity’s fine focus routine. Set the camera for 1-second exposures, get the spikes centered, and I am done.

While I have a couple of Bahtinov masks for my SCTs, I didn’t have one for my 5-inch refractor, and decided I wanted to make focusing less onerous with the lens scope. I could have made a Bahtinov mask easily enough. There are routines on the Internet that will draw a template for you. But the idea of fumble fingered me messing around with a sharp Exacto knife sounded like a recipe for disaster. I’d buy instead.

I have never been that happy with the SCT Bahtinovs I have. I just don’t like their mounting system or lack thereof. You lay them on the corrector, which isn’t really that great an idea in my mind. But who makes better ones? Coincidentally, one recent morning I got a Facebook message from a friend of mine, Andrea Salati. He mentioned therein that he had begun producing Bahtinov masks and wondered if I’d like to try one, “Sure.”

Andrea’s mask is great, well-made from sturdy plastic. But, let’s face it, a mask is a mask is a mask. What makes his different is the mounting system. It uses three adjustable pins in slots that allow you to size the mounting precisely for your scope (on mine, the pins go outside the dew shield). Neat. Elegant. A pleasure to mount and remove. I recommend Andrea’s mask highly and suggest you get one from him for your scope ASAP (he sells Bahtinovs for a range of apertures). Tell him Uncle Rod sent you: asalati@gmail.com

Can you? Should you? You can and you might want to for several reasons. Will it ever be as easy taking pictures with a 500 – 1000 dollar GEM as with a 10,000 dollar telescope mount? No. Not always, anyhow, but it is certainly possible to get deep sky photos that will please with one of these comfortably portable rigs.

Reading the telescope mounts forum on a certain popular amateur astronomy website, you might come to the conclusion that to just get started in imaging requires at least a mount in the 4K price range, and that actually getting decent pictures means you go to the 10K tier. Not so, not hardly.

As I have often said, what matters most is still the woman or man behind the camera, not the pedigree of the equipment. High dollar gear can make things easier, but as many, including one friend of mine, have found out, you cannot buy your way into deep sky imaging. This person has gone from Bisques to A-Ps searching for the elusive telescope mount that will take pictures for him without him having to endure the astrophotography learning curve. He has been disappointed. Mastering long exposure imaging takes blood, sweat, and tears, and no matter how modest your rig, you can get beautiful pictures if you understand your mount’s capabilities and limitations.

What do expensive mounts buy you? The payload capacity and precision to allow imaging at longer focal lengths more easily (if not always easily) than with lower priced GEMs. If your goal is to photograph smaller objects over long exposure times, certainly a high-dollar mount can help. But in the beginning, you need to learn the basics, which are easier to learn with a 500mm scope and a VX than with a 3000mm scope and an AP1100. Best of all? You won’t be out 10,000 George Washingtons if you decide astrophotography ain’t for you (not uncommon).

After gaining some experience, you may find your modest mount suits your needs perfectly well. That it is more than adequate for taking pictures at 500 – 1000mm (the sweet spot for the mounts we’ll discuss this morning), and you actually like the wider fields offered by this range of focal lengths.

M22 with an 80mm f/6.9...

Which telescope is best for these GEMs? To begin, I suggest a short focal length refractor, an 80 - 100mm aperture one with about 500 – 600mm of focal length, something in the f/6 – f/7 neighborhood. As we’ll see, this doesn’t mean you can’t kick it up a couple of focal length notches with the mounts in question—even to 1500mm—but make it easy on yourself in the beginning. Not only does a refractor in this focal length/aperture range make guiding/tracking easier, it lessens other problems. At 500mm, your mount’s goto accuracy is much less critical, for example.

As you probably know, f/ratio for f/ratio on extended objects—nebulae and galaxies—all more aperture gets you is a larger image scale, not fainter details. A 6-inch f/5 won’t go any deeper on extended objects than a 3-inch f/5; the object will just be larger.

OK. Which “500 to 1000” dollar mounts am I talking about? The Celestron Advanced VX and its predecessor the CG5, the Bresser (Explore Scientific) Exos-2 and its predecessor the Meade LXD75, and the newer and somewhat different iOptron CEM25. We might even stretch our budget range a couple of hundred dollars in order to include the Orion (Synta) Sirius (HEQ-5). The Sirius is a little heftier than the rest of the group, but has more in common with them than with the next group up (Atlas/CGEM, etc.).

One thing all these mounts have in common is that they are equipped with reliable goto systems. That is indispensable for imagers. Who wants to waste those increasingly rare clear nights (down here, anyhow) trying to find and center objects? They also all have acceptable tracking error figures, usually around 30 – 40-arc-seconds max, and the errors are smooth enough to guide out successfully. Exactly which of these GEMs to choose, though? Pick one. These mounts are all more alike than different. Here is the short and sweet.

Celestron Advanced VX

An 80mm refractor is great on a light GEM...

The modernized CG5. Its big plus is Celestron’s phenomenally accurate goto system. It also includes the AllStar Polar Alignment procedure in its hand control, which makes getting polar aligned well enough for the kind of imaging that is these mounts’ forte remarkably easy. Downcheck? Mainly the declination axis. No ball bearings there. Despite the fears of some novices, however, the VX guides well enough in declination. There’s some declination backlash, too, but less than with the older CG5.

Celestron CG5

The CG5 is robust and reliable—mine was working as well as it ever had when I sold it after nearly 10-years of service. I never had problems taking my (modest) deep sky astrophotos with it. There is no doubt the AVX rounded off some of the CG5’s rough edges, however. As above, my CG5 had a fairly large amount of declination backlash. Nevertheless, my guiding software, PHD, would always calibrate and guide successfully. While the CG5 has been out of production for several years, it is common on the used market, where it often goes for 400 dollars or less.

SkyView Pro

This Synta mount, sold by Orion in the U.S., is basically a CG5 with the SynScan goto system. In other ways, it is the CG5. The Synscan HC is fine, if not as full-featured and accurate as that of the CG5. Its goto targeting ability is quite sufficient for short f/l scopes, however. Unfortunately, from Orion this GEM is nearly as expensive as the arguably better VX.

Bresser Exos-2

This JOC made mount is very much like the AVX or the CG5 as far as payload capacity (see below), but it does have one plus: ball bearings on its declination axis. The minus? A somewhat primitive goto system. Accuracy should be OK for the smaller refractors we’ll use, at least. The mount also lacks a working serial port, so no interfacing to the computer. It does have an ST-4 port for auto-guiding, however.

The Exos-2

Explore Scientific, the U.S. seller (and JOC subsidiary), is promising a version with its new PMC-8 computer system (at a price similar to that of the VX, 900 dollar range), but that mount has not appeared yet. At any rate, the Exos-2 is one heck of a bargain despite its computer faux pas. You can get one for an amazing $599.99.

Before the coming of the Exos-2, the mount was available as the Meade LXD-75. JOC OEMed it for Meade, who installed their own goto system driven by the Autostar computer. If you can find a deal on a used LXD-75 in good working order, go for it. The Autostar is superior to the Bresser HC. While a few mechanical rough edges have been cleaned up for the Exos-2, the LXD-75 is usually a reliable performer much as the CG5 was. Do avoid the previous JOC made mount Meade sold, the LXD-55. The less said about that one, the better.

iOptron CEM25

This is the different kid. It’s one of iOptron’s “center balanced” equatorials. That offers several advantages, but the main advantages of this mount are its light weight, great polar scope, and quiet (stepper) motors. Downchecks? The mount's payload is less than that of the other GEMs in this group. It will handle a C8, but just barely. Also, the mount, which began as the servo motor equipped ZEQ-25, has had its share of teething problems. The latest version, the CEM25P, is, I am told, a fairly substantial improvement on the earlier versions, with iOptron guaranteeing +/- 10-seconds of periodic error.

Orion/SkyWatcherSirius/HEQ-5

The Sirius is an improvement over the VX and the others in some ways. There are ball-bearings for the declination axis, and it offers slightly higher payload capacity (as long as you get one with a 2-inch legged tripod) than the VX or Exos 2. The downside is that SynScan goto system, which, while OK, is kinda ho-hum regarding both accuracy and features. That’s not the whole story goto wise, though. You can use this mount (and the SkyView Pro) with the EQMOD ASCOM driver, which can offer much-improved accuracy at the expense of having to use a laptop with the mount every time.

Payload Capacity

The CEM 25 and the Sirius are the outliers here, with somewhat less and somewhat more weight handling ability respectively. The rest? For imaging, they are perfect with around 10-pounds or less at modest focal lengths. Astrophotography is a breeze with my 80mm f/7 APO. And the mounts are also OK with my 120mm f/7 refractor, which weighs in at a modest 11-pounds.

For any of these GEMs, a C8 is the practical upper limit for picture taking. The increasing weight and, moreso, focal length see to that. By the time you add camera and guide scope, you are really pushing any of them. Sure, you can use a C11 on a CG5 for visual, but that’s for visual. The bottom line for imaging? The less weight you can get away with, the better.

Balancing

Cropping allows you to zoom in a bit on an 80mm image...

What is one of the main things that can cause problems with tracking in this tier of mounts? They are a little sloppy gear-wise. In certain orientations, like when nearing the Meridian, loose gear mesh can mean the gears in the RA drive are not always fully engaged. The solution is simple: balance slightly east heavy.

“East heavy” is something needed by almost all mounts in this tier, and even the next group up, but I note considerable confusion as to what “east heavy” actually means. It’s really simple. You want the mount to always be slightly heavy to the east. That ensures the gears are always engaged; the RA motor pulls the scope along. This is not necessary for visual, and it won’t hurt the motors or anything if you are not slightly east heavy. It just helps the scope track better.

How do you do east heavy? If you are imaging on the west side of the Meridian, balance the scope and then move the counterweight up the shaft about ½ - ¾ inch or so. So the mount is just slightly telescope heavy. If you are imaging an object east of the Meridian, balance and move the counterweight down the declination shaft by that ½ - ¾-inch. The mount is now just slightly counterweight heavy. Yes, its’s best to re-balance if you switch which side of the Meridian you are imaging on. I usually find it easy enough to confine one evening’s run to either “east” or “west,” however.

Guiding

Can I tell you a story? One night I was out in the backyard imaging with the VX and my 80mm f/6.9 refractor. The brightness of the sky background on that evening due to slight haze was enough that I really had to keep my sub-frames, my individual exposures, down to about a minute. I sat at the computer and watched the subs begin to roll in. “PHD2 sure is doing a nice job of guiding tonight,” I thought. Then it hit me: I’d forgotten to start PHD2.

If you keep your weight and focal length down and can settle for 30-second to 1-minute exposures, you may not need to guide. The tradeoff is that if you want to avoid guiding you need to take extra care during polar alignment—I do two iterations of AllStar with the VX. Also, at 1-minute of exposure, you will likely have to throw out the occasional frame.

An 80 also has enough field for the big subjects...

If you do want to guide, the key is, again, keeping the weight down. Try to minimize the weight added by guide scope and guide camera. I use one of the 50mm finder – guide-scopes that Orion and KW telescopes sell. My guide cam is the sensitive but tiny (about the size of a 35mm film canister) QHY 5L-II. The 50mm finder is fine at 500mm of imaging telescope focal length, and does a nice job even at 900mm with my 5-inch APO.

Targets: What can you image at 500mm?

Actually, a 500mm – 600mm focal length telescope can be quite versatile. It’s equally at home photographing big objects like M33 or M45, or imaging somewhat smaller DSOs like the larger Messier globs. M13, M22, M10, M12—all are nice at 500mm or so. If you are using a larger high resolution chip, like the sensor on a DSLR, you can also “enlarge” your images somewhat by cropping and still retain nice-looking resolution.

Putting it All Together

Yeah, let’s put it altogether. First thing is setup. Get the scope and guide-scope and cameras on the mount, obviously. Not so obviously? Make darned sure none of the cables—you’ll have three usually: camera USB, guide camera USB, and ST-4 guide cable—can snag on the mount or the tripod. Double check and dress the cables as necessary after you go to the first target. These mounts are light enough that a cable snagging even momentarily will ruin the sub-frame.

Next, do the goto and polar alignments. If you are using a Celestron mount, think about doing two iterations of the ASPA procedure (with a new goto alignment after each). Celestron’s StarSense alignment camera can make that easy, doing the onerous goto alignments for you. iOptron? Their polar scope is excellent. If you are running the Exos 2 or one of the Synscan (Orion/SkyWatcher) mounts, I recommend the Polemaster polar alignment camera or the new polar alignment routine in the free program Sharpcap (which uses your guidecam and guide-scope, I am told).

Double Cluster with an 80mm f/6.9...

When you are goto and polar aligned, fire up the computer (or just the DSLR if you don’t use a computer with your camera), and focus on a field with a bright star in it. As I said last week, a Bahtinov mask makes that easy.

I like to control the mount with the computer (usually with the free program, Stellarium). Being able to sit comfortably at the PC and fine tune image centering with the little onscreen (ASCOM) hand control allows me to go longer than if I am constantly getting up and walking out to mess with the scope. Obviously, you can’t control the current Exos-2 mount with a computer since it lacks a serial port, but you could no doubt wire up a hand control cable extension and at least have the HC there with you at the computer.

Then…well, you just start taking sub-frames. How long should each be? That depends on the quality of your sky and the quality of your guiding. A bright sky can limit you to as little as a minute (or even less) of exposure. If your guiding tends to wander off, you may have to use shorter exposures as well (if you’d like the settings I use in PHD2 with my mounts, send me an email at rmollise@bellsouth.net). Seeing, atmospheric steadiness, can also limit the efficacy of your auto-guiding.

The 50mm guide-scope will usually deliver an RMS guiding error of about 2” in my experience. That is more than good enough for the image scale delivered by 500mm or even 900mm of focal length, as long as your declination and RA guiding corrections are of similar magnitude. I generally find myself doing 4-minute and shorter exposures depending on the target and sky conditions.

Going Longer

Will one of these mounts support imaging with more focal length and weight? Say with a C8 (reduced to f/6 or f/7)? Yes. I wanted a new C8 at the time I bought my VX, and ordered it with the Edge 800. It seemed natural to try a little imaging with the new scope on the new mount. I’ve been able to attain pleasing if not utterly perfect results with the f/7 reducer. If I’d been more careful with polar alignment and balance, my results would likely have been even better. One important thing? Don’t consider shooting at 1500mm with the VX (or the other mounts) on any but calm nights. A strong breeze will wreck your photos tout suite.

VX + C8: it can work...

Would the AVX or any of the rest of these mounts be my choice for imaging with a C8? No. Not at all. For that, you really want the next group up, the Atlas/EQ-6 (or the Pro variant), the CGEM, the CGX, or the iOptron iEQ-45 Pro. You can shoot at 1300 – 1400mm with the AVX group, but it will never be as problem free as at 500 – 900mm.

There is one thing that encourages me to use a C8 on my VX, though: I’m lazy. I’ve had excellent results with the SCT on my CGEM and Atlas, but they are so darned heavy compared to the VX that whenever possible I prefer to use the lighter mount. That’s the trade-off if you can’t afford to play in the GEM big-leagues. You can get lower priced mounts with good payload capacity like the EQ-6, but in order to increase the payload, the mount head’s weight goes way up as compared to something like the Astro-Physics Mach One.

I can’t—or at least won’t—afford a Mach One, and I can’t always convince myself to drag out the Atlas or CGEM. So, I’m willing to put up with a little hair pulling when I think I need a C8 to image what I want to image. But you know what? With a little care, these humble mounts, the VX, the Exos 2, the CEM25, and their kin, can still bring home the bacon in the form of beautiful pictures.

Better still? One of these mounts and an 80 – 100mm refractor makes for a setup that is so light, easy to transport, easy to assemble, and effective, that even jaded old me doesn’t mind heading out to the dark site occasionally for an evening of relaxed picture taking.

If you are using an equatorial mount, fork or German equatorial, for imaging, that mount has to be accurately polar aligned. The right ascension axis has to be pointed precisely at the North Celestial Pole or South Celestial Pole. If it’s not, longer exposures will suffer from a phenomenon called “field rotation,” which makes stars trail no matter how accurate the guiding. Heretofore, there were basically two ways to polar align a mount, the easy way or the hard way.

The easy ways? One was to use a polar borescope on a GEM. Once you figure out how to set it up, a polar finder can yield alignments ranging from excellent to usable depending on the borescope’s manufacturer and your expertise in using it. For many folks kneeling on the ground to peer through that dim little telescope in quest of a sometimes-rough polar alignment (unless you have a Takahashi mount and its excellent polar finder) is a bummer. Also, no truly accurate polar finder has ever been produced for fork mount telescopes, though some people, like the late Roger Tuthill, have tried.

Another fairly easy polar alignment method is “Kochab’s Clock.” That involves lining up the RA axis with the help of one of Ursa Minor’s stars. Kochab’s can potentially yield a good alignment if done with care, but in most cases, not a sub 5’ – 10’ alignment.

Finally, there is the sure thing, a declination driftalignment, which, unfortunately, most of us don’t consider overly easy. Or at least not overly quick. You observe a pair of stars near the Celestial equator, and watch their drift in declination (through the main scope) as the telescope tracks, adjusting the mount’s altitude and azimuth controls until there is no significant north/south drift of either star over at least five minutes of time.

“Drifting” is not hard once you get the hang of it, but it does take time, and you have to be able to acquire suitable stars, one near the intersection of the Celestial Equator and the Local Meridian, and one near the Celestial Equator and about 15 - 20 degrees off the eastern or western horizon. That’s not always possible at every observing site.

And there things remained for years. In the 1990s, I used a fork mounted SCT, and did a two-step polar alignment. First, I’d rough it in using a 50mm finder scope with a polar alignment reticle. That was, as above, not a recipe for a good alignment on a fork mount scope, but it at least got me in the neighborhood. Then, I’d go on to drift, which took about half an hour or so once I gained some experience. I never liked drifting, though, and for that reason I usually quit before my polar alignment was quite good enough for the long exposures required in the film astrophotography days.

Typical polar borescope finder reticle

Flash forward ten years or so to the coming of the computerized GEM mounts like the Celestron Advanced GT CG5. One of the big breakthroughs with the CG5 (and also a few other brands) was an automated polar alignmentroutine. With the CG5, you did a three-star (no 2+4 in the firmware’s early days) goto alignment. You then requested “Polar Alignment.” The mount would then point at Polaris, and over the course of a couple of steps would slew away from the star. You’d then re-center Polaris using the altitude and azimuth adjusters. While you would be centering Polaris in the eyepiece, what you’d really be doing would be offsetting the RA axis to place it on the true Celestial Pole about ¾ of a degree away from Polaris (the routine also worked in the Southern Hemisphere).

This procedure didn’t produce a great polar alignment, but it was a little better than what I could do with the CG5’s (pitiful) polar borescope, and it was definitely quicker. It was sufficient for the short exposures at short focal lengths I was doing with my Meade DSI CCD camera at the time.

Then came Celestron’s new polar alignment routine, AllStar Polar Alignment, ASPA, in late 2008. This alignment procedure was different mainly in that it allowed you to supposedly use any star (other than Polaris) for polar alignment. We eventually found out a good ASPA star was not really any star, but a star due south and on or lower than the Celestial Equator. Get a good star, do two iterations of ASPA, and you’d have a close enough polar alignment for most imaging tasks.

While AllStar was not inherently more accurate than the old Polaris system, it was coupled with the new and much more accurate 2+4 goto alignment in Celestron’s updated firmware. With these types of polar alignment routines, the better the goto alignment, the better the resulting polar alignment. How accurate was/is ASPA? You’ll wind up about 10’ away from the pole or a little better, usually, with one iteration.

The downside? If you wanted better than that 10’ or thereabouts, you needed to do two ASPAs. That could be a bummer since you’d normally want to do a new goto alignment after each ASPA (or at least “replace” the last goto alignment star). If you chose to do a new ASPA after each iteration, by the time all was said and done you’d have centered as many as 18 stars for goto alignment. The automated StarSense alignment camera made doing two ASPAs a little more palatable, but you’d still be spending around twenty minutes doing goto and alignments.

Nothing changed for nearly another decade, till the enterprising Chinese CCD camera maker, QHY, came up with a new idea, which they called “Polemaster.” I was skeptical at first. A tiny camera not much different from my QHY-5LII guide camera save for the addition of some wide-field optics would be mounted in place of the mount’s polar borescope on the forward end of the RA housing. You would point the RA axis roughly toward the pole, toward Polaris, and the cam would plate solve the star field and tell you how to move the mount for precise polar alignment. That seemed like a pretty tall order to me.

Polemaster camera...

How would the alignment of the Polemaster camera affect the resulting polar alignment? How would you mount the cam if your RA axis didn’t have provision for a polar borescope? Or you didn’t want to remove or block the polar finder? Even if everything was perfect, how precise an alignment could a small-chip camera like the Polemaster produce?

When I had the chance to see the Polemaster in action at the Maine Astronomy Retreat last summer thanks to my friend Bruce Berger, all my doubts were dispelled. The camera was completely sufficient unto its task, producing more than enough stars in short exposures to allow it to do its job. The real key, however, was the software. Once I had a good understanding of the process, it was obvious what you had to do to move the mount’s RA axis to the pole. Not just obvious, but quick. If you are in a hurry, you could probably the entire Polemaster polar alignment in five minutes.

Further, I later learned the mounting of the camera was not critical. As long as it is attached to the mount somehow, someway in reasonably secure fashion it will work. I’ve seen people use it successfully, for example, just by duct-taping it to the mount head. Alignment is also not an issue. The camera does not, repeat, does not have to be finely aligned with the right ascension axis.

Watching Bruce polar align his CEM 60 quickly and precisely, I decided this was just the solution I had been looking for. Well, it would have been save for one thing: the price. While the Polemaster is not overly expensive, about $300.00 with an adapter for one telescope mount, that was more than I wanted to pay given that ASPA was working pretty well for my purposes, with its main problem being it was time-consuming and occasionally annoying.

Annoying? Yes. There’s a bug in the Celestron StarSense firmware that sometimes causes the auto-align process to fail after the ASPA (and StarSense requires you to do another goto alignment after ASPA). It’s not a big deal to turn the mount off, reset it to home position, and start another StarSense align from scratch, but it is annoying.

Oh, and I would have liked a little better accuracy than what ASPA produces, especially after only one iteration. For my (mainly) short focal length, short sub imaging, I can get away with less than perfect polar alignment, but it would still be nice to have the option of being able to expose longer thanks to a better polar alignment.

Initially, I was hoping QHY might have pity on us and sell their software separately. I figured my QHY-5LII would work just fine for polar alignment in conjunction with my wide-field 50mm finder-guider. Alas, they have not seen fit to do so; the software will only work with the Polemaster cam. So, I continued ASPAing it. What else could I do?

Then one day a couple of weeks back, I began to hear about Sharpcap’spolar alignment tool. I was well aware of Sharpcap itself, Robin Glover’s fantastic camera control program. Despite its somewhat nondescript and generic name, Sharpcap is a well-respected piece of astronomy software. It began as a tool for planetary imagers using webcams and webcam-like cameras, but has evolved into a program that can do long exposure deep sky work easily and well. Sharpcap is compatible with just about any camera out there as long as there is an ASCOM driver for it. Best part? Sharpcap is free.

Screen 1

Anyhow, I was told the latest release of the program, version 2.9, included a polar alignment routine similar in concept to that used on the Polemaster. A visit to the Sharpcap website revealed I had everything I needed to give this Polar Alignment Tool a try: a compatible camera (the QHY-5LII is supported natively by Sharpcap), and that short 50mm guide scope. All I needed was one of those increasingly rare clear nights to give it a try. I read over the instructions a time or two in preparation, but, frankly, there isn't much to the procedure once the camera is connected to Sharpcap. Press an onscreen button a few times, move the mount once, and adjust the polar alignment with the mount’s altitude and azimuth adjusters.

That nice night finally came, and saw me setting up my AVX mount and Celestron Edge 800 SCT in the backyard. Why the AVX? It’s light and I am lazy, as I admitted not long ago. The SCT? I figured the scope’s long focal length would serve to reveal how good Sharpcap’s polar alignment results are. Further, I needed to take a few Moon pictures for a magazine article I am writing, and 4000mm (with a 2x Barlow) is just right for high resolution lunar vistas.

I put the telescope in normal “home” position, that is, pointed north with the counterweight “down.” The QHY was inserted into the guide scope and connected to the computer, which I positioned (temporarily) right next to the scope so I could adjust while watching the indications on Sharpcap’s screens.

First task was getting an image, a focused image. That was easy enough to do (well, after I remembered to remove the lenscap from the guide scope). Once I was close to focus, the sensitive QHY was producing more than enough stars to meet Sharpcap’s requirements in a mere 1.5 seconds of exposure. To work, the program needs 15 stars within 5-degrees of the pole, and according to the information on the first polar alignment screen, I was getting more than twice that many despite a crescent Moon and the usual backyard light pollution.

Ready to go, I clicked Sharpcap’s Tools menu and selected “Polar Align.” I was then presented with Screen 1, shown here. Stars marked in yellow are the ones Sharpcap is using for plate solving the star field (figuring out which star is which). I didn’t worry about that, just let the program think for a little while as the frames rolled in. Shortly, the “Next” button was enabled, meaning I was ready for step 2.

After pressing “Next,” screen 2 was presented and I was instructed to rotate the mount 90-degrees in right ascension. I did, so, moving the mount roughly 90-degrees to the east. Sharpcap then studied a few more frames in order to determine where the Celestial Pole was and what I needed to do to aim the mount there. Once it knew these things, the Next button was enabled again.

Screen 2

After pressing Next for a final time, a star was highlighted in yellow and there was a yellow arrow connecting it to a circle, my target . The task was to move the mount in altitude and azimuth so as to position the star in the little circle, not unlike what you do with a polar borescope (by the way, you don't need to return the mount to home position before adjusting; leave it rotated 90-degrees). As you move in the proper direction, the yellow arrow gets shorter and shorter and eventually disappears. It is then replaced with a pair of brackets around the target to allow fine tuning. As you center the star in the target circle, the brackets will move closer and closer together.

How easy was this to do? Quite easy AFTER I understood exactly how to do it. In the beginning, I was fairly far from the pole, with the arrow extending off screen. I’d been told that at this stage it was best to adjust while watching the error numbers Sharpcap displays instead of worrying about the arrow. These numbers (degrees, minutes, and seconds) indicate how far you are from the pole. They aren’t labeled as altitude and azimuth; instead they read “Up/Down” and “Left/ Right.” Sounded easy to me. I’d adjust the mount’s altitude until the Up/Down number got smaller, and the azimuth till the Left/Right went down. Alas, that didn’t work at all.

It turned out there was a catch, and until I understood what it was, I was all at sea. Up/Down does NOT mean the mount’s altitude, and Left/Right does NOT equal azimuth. Instead, these error numbers relate to directions onscreen (that's what I thought, anyway; see the addendum at the end of the article). At first I was mightily confused by the fact that moving in azimuth changed the Up/Down distance instead of Left/Right, and vice versa. As soon as the light went on in my head, that moving the mount’s altitude control changed the Left/Right distance, and adjusting azimuth affected “Up/Down,” the rest was duck soup.

In just a minute or two, I had the program indicating my distance from the pole as under a minute in both directions, which was where I left things. If your mount has precision altitude and azimuth adjusters, you can get the distance lower, but the AVX’s controls, while OK, are not exactly precise.

How long does a Sharpcap polar alignment require? Next time out, I doubt the procedure will take any longer than the few minutes required by Polemaster. Most of my time was, as above, spent scratching my head wondering why adjusting altitude moved the darned Left/Right numbers.

Screen 3

The accuracy? Some night soon, I need to fire up PHD2 and find out exactly how good Sharpcap’s polar alignment is. I know one limitation is that I am a little close to the equator at 30-degrees north, and that since the program does not currently take refraction into account there will be a limit to how close it will get me. However, I will tell you it looked darned close on this first night given the declination drift (or lack of it) of the Moon and stars at f/20. It was obvious the alignment was at the very least as good as two iterations of ASPA, and likely better.

Ground truth? I doubt I’ll use ASPA anymore. Now that I understand Sharpcap’s procedure, its Polar Align Tool is just easier and, I believe, more accurate. Sure, to do it you have to have the guide scope and guide camera mounted on the telescope, but if you are after a precise polar alignment you likely will be imaging and will want to guide with that guide cam and scope anyway.

So, friends, why not bop on over to the Sharpcap website, download the program and give it a try? Don’t cost nuttin’, and its polar alignment feature is only one of the many good things this wonderful program offers. At the very least, it’s made me stop wishing I had a Polemaster, and has allowed me to keep 300 George Washingtons in my hot little hands.

Addendum: Just heard from Robin (see the comments) concerning the "direction" issue that I and some other people are having. He says that moving the polar axis up or down arrows should indeed affect the up/down numbers. At any rate, the program works great despite the direction reversal, and what's important is to shorten that arrow, which I found easy to do once, as above, I understood what was happening.

PHD2, that is, as in America’s premier auto-guiding software. I have written about the program, originally done by software wizard Craig Stark and now carried on as an open-source project, a time or two before, but lots of people still have lots of questions about it. It’s rare that my virtual mailbag doesn’t contain a missive pleading for help with PHD.

Before offering some of that help, I suppose I should explain what PHD2 is for the uninitiated. You’re probably more knowledgeable than I was when I began astrophotography. Unlike me, you know you can’t just point your telescope and camera at a deep sky object, open the shutter, and walk away. You have to guide. The gears in most mounts are not precise enough to allow the scope to track precisely enough over longer exposures to keep stars round without some intervention.

To keep stars round, you watch a “guide-star” either with the main scope or a small auxiliary telescope, a guide scope, keeping it precisely centered. Or a little camera does that watching for you. There are some mounts that will allow you to dispense with guiding for long exposures, but you are talking about mounts in the 10micron class, expensive, top-tier mounts. Proletarians like yours truly guide their mounts throughout long exposures.

How exactly do you do that guiding? Well, back in the day, you monitored a guide star in a crosshair eyepiece in the guide scope or in an off-axis guider, and pushed buttons on a hand-paddle—what we called our non-computerized telescope mount hand controls—to keep the star centered. Naturally, when computers and CCD cameras came along, we were more than happy to pass the onerous task of guiding to them.

A guide camera is used to watch that guide star, but most guide cameras cannot guide the telescope mount without the help of a laptop computer and an auto-guiding program. That program is the brains of the outfit, and that is what PHD2 is, auto-guiding software.

If you need direction on getting PHD2 downloaded, installed, and initially configured, please see this (fairly) recent article. Today, we’re going to focus on what you need to do to get PHD2 performing by fine-tuning its default parameters. What you have to do to get those pesky stars round.

What does “PHD” stand for, anyway? It ain't “doctor of philosophy,” but instead, “push here dummy.” Mr. Stark’s original goal was to produce an auto-guiding program that was as simple as it could possibly be. One that would allow you to hook everything up, push one button and guide your way to round star heaven. That’s actually possible in some cases, but due to the nature of the beast, often not.

The Guiding Tab...

There are so many different possible configurations of telescope/guide scope/guide camera/main camera/telescope mount, etc., etc. that making a no-set-up auto-guide program is a near impossibility. Oh, if you stick to shorter focal lengths (500mm and down) on a decent (VX and up) mount, and don’t insist on longer than 300-second sub-frames, it is possible all you will have to do is push that button and guide. Most of us will have to mess with PHD’s guiding parameters, which are accessed with the program’s famous brain icon. Before we attack that, though, a couple of preliminaries: “What is the best way to guide?” and “What is the best guide-scope to use?”

I am frequently asked by newbies how they should guide. Should they use an ST-4 connection, a direct connection from a camera to a mount’s auto-guide port, or should they guide through the hand control’s serial port? I asked myself that very thing years ago when I first essayed auto-guiding.

Some people think serial port guiding, particularly “pulse guiding,” a feature of some ASCOM telescope drivers, is better since each guide message going to the mount contains not just the direction the telescope needs to move, but also for how long. With ST-4 guiding, once the software decides the mount needs to move, it will cause the camera to close an electronic “switch” to move the mount. When the move is done, the switch is opened. With pulse guiding, there is no (possible) time-lag resulting from ST-4 mode guiding having to send an additional command to open the switch. On the other hand, ST-4 fans say that since no back and forth computer talking is needed with ST-4 mode guiding, it must be inherently more responsive.

The ground truth? With my mounts/scopes/guide-cams, there was absolutely no difference in accuracy between the two methods. The pluses for each have more to do with convenience. If you are controlling your mount with a computer, why not pulse guide? If you are using EQMOD in particular, that seems a natural—everything, goto commands and guide commands, is routed to the mount over a single cable. On the other hand, while ST-4 guiding requires an additional cable run from camera to mount, there’s no fooling around with serial connections and USB to serial adapters, which is a good thing. I normally do ST-4 for that reason.

Calculating cal step size...

The other question concerns the guide-scope or lack thereof. What sort of a guide-scope should you use? In my opinion, the answer is one with a focal length of about 400 -500mm. That provides a fairly wide field for small guide-cam sensor chips, but also has enough image scale for precision guiding. The venerable Short Tube 80mm is a good choice as long as you can lock the focuser down firmly and mount the whole thing securely to prevent image-destroying flexure.

Me? I use a short focal length 50mm finder-guider. One of these will work up to about 1200 – 1300mm of imaging scope focal length, and is small, light, and easy to mount firmly. For anyone who doesn’t top 1000mm of imaging scope focal length, a finder-guider is a natural. Having that wide field is often a blessing when it comes to choosing guide stars.

There’s always the option of doing without a guide scope, too. Using an off-axis guider (OAG) which intercepts a small amount of the light coming out of the main scope for guiding. Obviously, since you are guiding through the main scope, there is no flexure to worry about. If you are running an imaging telescope at over 1500mm of focal length, you may find an OAG is your only workable option. The downside? You only have access to stars at the edge of the main scope’s field, and for that reason it can be quite difficult to find a good guide star. Luckily for me, a long time OAG hater, I rarely image at a focal length long enough to require one.

One final thing to discuss before we do “brain surgery.” How good does your guiding have to be?How much error is acceptable? The answer is, “that depends.” At 1000mm or less with an APS-C sized camera sensor chip, an RMS error of around 2” or so is good enough. Stars will be round and small enough to please. You can even get OK (if sometimes not perfect) stars at that error level to about 1500mm of focal length.

It’s a good thing this degree of error is acceptable at the focal lengths I use, since the plebian mounts I have in my inventory, GP clones like we discussed last week, and the EQ-6 and CGEM mounts a step above them, will deliver 2” of RMS error with fair ease. Getting guiding much tighter than that with these sorts of mounts isn’t always easy and will often take considerable experimentation.

Alright, click PHD2’s brain icon and let’s get started entering some guide parameter values in place of the defaults, parameters than will bring us round stars (we hope). With the brain window displayed, skip its first two tabs, “Global” and “Camera,” since I’m assuming you’ve gone through them in the initial program setup. Which brings us to…

Guiding Tab

The Algorithm Tab...

The first entry here is “Search Region.” This is the size of the tracking box PHD2 draws around a star. Normally you should leave this at the default value. If you have so much drift between guide exposures that the box needs to be larger, you aren’t going to get anywhere with guiding anyway. The accompanying “Star Mass Detection” has to do with PHD2 monitoring the star’s brightness as compared to the sky background. Leave this as is as well. Likewise, leave the tolerance setting for Star Mass Detection alone.

The next part of the window is quite important, “Calibration.” Enter the focal length of your guide scope (you should already have entered the size of the guide-cam’s pixels in the “Camera” tab), push the button labeled “Calculate,” and PHD2 will figure out how long guide pulse duration should be during calibration. The main concern here? If you have a short focal length guide scope like I do, you need to enter a much higher calibration step size than the default. I have a value of 1350 here. Given the short focal length of my 50mm finder-guider, I need that large a setting. Otherwise, calibration would take all freaking night to complete. Leave the other stuff here alone.

The final part of the window contains things you don’t have to worry about in the beginning. Well, except for one thing. Make sure “Enable Guide Output” is checked, otherwise PHD2 will not issue guide commands to the mount. It will be like that goober in the TV commercial, “I’m not a dentist; I’m a DENTAL MONITOR.”

Algorithms Tab

Here’s where we get down to the nitty gritty, the place where you can change the settings that really and truly affect guiding. You’ll see that the window is divided in two, with one area for right ascension and one for declination. Let’s begin with RA.

The first thing to set is Hysteresis. PHD2 is pretty smart; it can remember what the last RA correction was like and use that information in formulating the next correction. The number here is a percentage. It is how much the remembered previous correction affects the next one. At 40%, the next RA correction will be 40% based on the magnitude of the previous correction, and 60% on the star movement PHD2 is seeing at the moment.

Guiding Assistant...

What should you set it at? More Hysteresis yields smoother guiding. Too much, however, and a sudden guide star movement will not be adequately compensated for. I have my value at 40%, which seems OK.

Coupled with Hysteresis is “Aggressiveness.” That setting is how much (as a percentage) of the calculated necessary movement PHD2 actually sends to the mount. The reason for this is to decrease the chance of the mount overshooting the star, going back the other way on the next guide command, and overshooting in that direction too, “ping-ponging.” Normal settings rage from about 70% to 100%. I am set at 85%.

Next is “Minimum Move.” This is the amount the star is allowed to drift without PHD2 issuing a guide command. The reason for this is to reduce unneeded guiding corrections caused by non-tracking related star motions due to seeing or other momentary events like mount vibration, wind, etc. The default is .15 and that’s where I’ve left it.

Max RA duration, the last setting on the RA side, is similar to the above in that it’s meant to smooth out guiding, to prevent herky-jerky guiding. This figure is in milliseconds, and limits the duration of the RA guide command. I’ve settled on a value of 1200 for RA through trial and error. I am thinking that is low, however, and might try a higher value next time out.

Now for the declination side of the house…

First up is “Resist Switch,” which means PHD2 tries to avoid reversing the guide direction in declination. That is always a good thing, since in many cases issuing a guide command in dec to go back the other way will be a problem. Star movement in declination opposite the constant slow (you hope) drift caused by polar alignment errors is usually caused by seeing, vibration, mount flexure, wind, etc., and as with RA, we want to avoid issuing guide commands for these things. Most of all, many mounts have considerable backlash in declination, which would create a considerable time lag between command and movement if the mount reversed direction in dec.

Also on the declination agenda are aggressiveness, minimum move, and backlash compensation settings. I have the first two at the same value I have for RA. The backlash compensation option determines whether PHD2 will use a backlash compensation value it has computed if a declination correction opposite the previous one needs to be issued. I have this off, since I don’t seem to be having any major dec problems.

Max Dec Duration has the same purpose as in RA, to smooth guiding. I have my value set a little higher here than I do in RA, 1500, but it could probably be higher still.

Finally, there is “Dec Mode.” Normally this is set to “Auto,” which tells PHD that the occasional declination reverse guide command (caused by whatever) is permissible. Why would you want to disallow this by selecting “North” or “South”? If your mount has really bad declination backlash, trying to make a “reverse” correction may cause serious problems—the cure may be worse than the disease. I am set to “Auto.”

And that is it, folks. The other Brain tabs cover use of adaptive optics guiders and are of little interest to most of us.

Getting round stars with an import mount is fairly easy at 900mm...

How do you fine tune your mount if these values don’t work for your particular setup? Trial and error, which was what I did to arrive at the numbers I’ve given here. There is one alternative, though, PHD2’s “Guiding Assistant.” Theoretically, invoking this tool should allow the program to decide what your guiding values should be. When the procedure has completed its work, it will make suggestions, which you can implement or ignore at your discretion.

Alas, when I tried Guiding Assistant some time back, one night at the 2015 Peach State Star Gaze, the figures PHD2 came up with seemed to make my guiding worse rather than better. However, that was over a year ago, so the Assistant may have been improved by now. If you invoke it and use the suggestions, make sure you’ve written down your old numbers so you can get back to the way things were if Guiding Assistant doesn’t work for you.

I hope all this stuff didn’t put you off too much. Again, with a halfway decent mount and a reasonable focal length, you might not have to do much with anything beyond basic setup other than just setting your calibration step parameter. And remember, if your stars are round your stars are round. Don’t start chasing lower and lower error values just for the sake of lower values, “The Only Enemy of Good Enough is More Better.”

In our pre-spring observing season drive to get novices (and maybe even a few not-so-novices) set up with a rig for deep sky imaging, we’ve addressed mounts, telescopes, and, last week, auto-guiding setups. This Sunday we’ll finish with suggestions for a low-cost camera. I’ve talked about imaging cameras with y’all fairly recently, but the difference is that this time I’ll try as hard as I can to keep the cost as low as possible.

So, you need a camera and a few accessories. Where do you start? The first question to answer is, “Do I want color?” While a monochrome CCD/CMOS astronomical camera can take color images by exposing successive frames through three or more colored filters, it’s not something you want to face when you are just getting off the ground in imaging. Unless you enter the ranks of the hard-core someday, you may neverwant to face it. In the beginning you will find just processing a “one-shot” color image enough of a challenge. Properly calibrating and combining three + separate frames into a color frame and then stacking and processing a bunch of those? Uh-uh.

So, it’s a color camera, a one-shot color camera, you want. How does one work? A color camera is different from a monochrome camera in that red, green, and blue color filters are built into the sensor chip. Software, either in the camera or in an image processing program, automatically combines the R, G, and B to produce a full color image. That is usually transparent to the user—with a digital single lens reflex (DSLR), anyway. You take a picture, you see a color image, end of story.

Some astrophotographers say a monochrome camera can produce visibly higher resolution images because it doesn’t waste pixels on the production of a color image. In truth, in the beginning at least, and especially on deep sky objects, you won’t notice any difference.

The next question is “CCD or CMOS?” That is not much of a question today. Unless you are interested in some special applications, mostly having to do with obtaining scientific data, there is no reason to choose a CCD chip over a CMOS chip. Today, the formerly preferred CCD has lost ground to CMOS sensors even for use in “astronomical” cameras. CMOS chips are now very sensitive and very low in noise. At any rate, almost all cameras in our price range, which I am topping out at 450 dollars, have CMOS chips, so the choice has already been made for you.

What a ZWO ASI120MC can shoot...

Next up, cooling. “Does a camera for taking long-exposure images need to have its sensor chilled to reduce thermal noise?” Today, probably not. With some camera/chip combos, an internal fan, at least, can be helpful to reduce the false stars of thermal noise, but the low-noise characteristics of today’s sensors usually means subtracting a dark frame is enough to deal with thermal noise.

And the Final Jeopardy Question… “Astro cam or DSLR?” There are some interesting low cost astronomical cameras coming on line, like those from China’s ZWO, and I’ve actually taken credible deep sky image with one of their 1/3-inch cameras that cost a measly 200 dollars. However, I think for most of us a DSLR is just a much more sensible choice. A much more sensible choice.

Why is a DSLR better? There are several reasons, but there is one real big one: when you’re not taking pictures of the night sky, you can be wowing everybody at your mother-in-law Margie’s birthday party with your snapshotting skills. There’s also that big elephant in the living room. Like many wannabe astrophotographers, a few nights wrestling with camera and scope may convince you you are actually more of a visual observer. If that be the case, you can still get years of use and enjoyment out of the DSLR, even if you never take another astrophoto with it.

Another big plus (for astro imaging) of the DSLR? Their relatively big chips. A less than 500 dollar camera will have an APS-C size chip. Lower cost astro-cams tend to have small chips that restrict your field of view, focal length for focal length, and also tend to make guiding more critical.

Finally, while I control my DSLRs with a program running on a laptop (“tether them,” as we say in the photography business), which makes focusing and framing much easier, you don’t haveto do that. You don’t have to have a computer out in the field when you are taking pictures. You can do just as we did in the SLR days: telescope, mount, camera. You will, as in those SLR days, need a remote camera release (an intervalometer, preferably), but that is it.

OK, so which DSLR? The safe thing to say is still “Canon.” In some ways they still lead the pack in astrophotography. The Canons are remarkably low in noise over long exposures, and are easy to use in the field with a laptop if you choose to do that. Things are changing now, but until recently camera control software (like Nebulosity) was unheard of for other brands.

SCT Prime Focus Adapter

There’s also Canon’s longstanding involvement in our game. While Nikon and, now, Pentax are coming on strong for astrophotography, until the last couple of years only Canon acknowledged people were actually using their cameras for astronomical imaging and produced cameras with astronomy in mind.

Canon is a safe choice, in my opinion, but which one of their many DSLRs? If you are buying new and must keep the price tag low, the Rebel T6, which is available for about 450 dollars, is a remarkable value. Not only do you get a DSLR that will perform well for astro-imaging or anything else, you get a pretty good (zoom) kit lens for use in wide-field astrophotography or at Margie’s above mentioned b-day party.

Just don’t want a Canon for whatever reason? The equivalent Nikon is the D3300, which is even less expensive than the Rebel. And it can perform very well for astronomical imaging. BUT… Computer control options for this camera are (very) limited—it is not supported by the major Nikon astrophotography program, BackyardNikon—so if you want to tether camera to computer, a Canon is a far better choice.

How about buying a used camera? Is that a good idea? That depends. A fairly recent camera or seldom used older camera can push prices even lower. A perfectly serviceable older Rebel, like a 450D, for example, goes for 150 or fewer dollars with a kit lens and a few accessories. Be careful here, though. While the Rebels, Canon’s introductory DSLRs, and Nikon’s comparable models are well-made, they are not professional grade cameras and won’t stand up to real abuse. So, when considering an inexpensive camera it’s best to limit yourself to one that’s for sale locally so you can examine it in person and make sure it’s fully functional.

Accessories

Prime Focus Adapter

Prime focus adapter (1.25-inch)...

Once you’ve got a camera, of course you’ll need accessories. You always need accessories in astronomy, you know that! First off, you will need a prime focus adapter in order to connect camera to telescope. “Which” depends on your scope style. SCT prime focus adapters screw onto the SCT’s rear port. Those for other telescope designs, like refractors, typically have 1.25-inch or 2-inch nosepieces and slide into the scope’s focuser. I like the 2-inch models, not because you have to worry about vignetting or something like that with an APS-C size sensor, but because they allow me to dispense with a 1.25 – 2-inch eyepiece adapter and seem to provide a more secure mounting arrangement.

T-ring

You’ll also need a t-adapter for your camera, aka a “t-ring.” This is a, yes, ring shaped adapter with T-threads on one end to screw onto the prime focus adapter, and a lens mount for your particular camera on the other end. These two things in hand, you can remove the camera’s lens, mount the combo of T-ring/prime focus adapter in its place, and then mount the camera on your scope by inserting everything into the focuser or screwing the prime focus adapter onto the rear port of an SCT.

Intervalometer

As you may know, DSLRs, most of them anyway, and certainly all the Canons, can’t expose for more than 30-seconds without the addition of a remote shutter release. Even if your camera couldexpose for longer without a remote, you’d still want one as it allows you to trip the shutter without bumping the scope and causing trailed stars.

T-ring

An intervalometer is a remote shutter release, but it’s also much more. Not only will one of these (usually) wired controls allow you to trip the shutter from a distance and expose for as long as you like, it will allow you to shoot sequences of images. Say 30 3-minute exposures, which is exactly what we want to do. An intervalometer allows you to do many of the things a tethered computer would allow you to do, but without the computer. How much? A Vellois about 50 bucks and a genuine Canon is about three times that. Guess which one I’d choose?

Memory Card

If you’re not using a tethered PC, you’ll have to have a memory card, digital "film" on which to store your images. An SD card (used by almost all DSLRs, now) with at least 64gb capacity is my recommendation—you’d be surprised how much space an evening’s images can take up. Get a good, decently fast card. I like the Sandisk ones. About 40-bucks.

Battery

If you’re going to use a battery, make sure you keep an extra, or, better, two extras in your gadget bag. During long exposures, the camera is drawing current from the battery continuously, and you’re unlikely to get a full evening out of one cell, especially on cold nights. There are lots of third party batteries available, but I have had noticeably better performance out of genuine Canon, so that’s what I recommend here, the real deal, for a change.

Power Supply

Yes, batteries are a problem during astrophotography, so don’t use one, or use a real big one. Hop on over to Amazon and buy yourself either a 12vdc or 120vac power brick for your Canon (or whatever). I do most of my shooting at locations with mains power, so I prefer the AC option. The DC supplies have cigarette lighter plugs that will plug right into your jumpstart battery pack.

What do you plug one of these things into on the camera end? These power supplies have little plastic (wired) widgets that take the place of the normal battery in the battery compartment and supply power to the camera that way. I’ve found one of the inexpensive—less than 15-dollars—units on Amazon to work just fine, but Canon will sell you one for considerably more if you like.

Anything else? Well, a few things, maybe. If you are new to DSLR photography, you probably want a camera bag, a gadget bag, to keep camera and lenses and, well, gadgets, together. A nice piggyback bracket so you can mount DSLR and lens on your telescope tube is a nice addition and you may find you like doing wide-field shots from dark locations. A lenspen is good to keep your lens’ surface pristine. A broadband light pollution filter can be helpful if, like me, you do some of your imaging from an at least somewhat light-polluted backyard. And that is really more than enough to get you started.

You’ve now got all the pieces to the complicated astrophotography puzzle, but how the heck do you put them together? We’ll talk about that, about getting started with all this stuff, next week.

Addendum: How good can a VX be?

Auto-guiding wise, that is. Some of you considering a Celestron Advanced VX mount (or the similar mounts on the market today) have expressed grave concern about my statement last week that 2” (arc seconds) of RMS guiding error is about what you should expect of this group without some fine-tuning (of PHD’s Brain Icon settings, I mean).

Anyhow, while 2” is perfectly suitable for some image scale/camera pixel combos, naturally it would be nice to do a bit better with this inexpensive and highly portable GEM. So, I set about the other night to see how much and how easily I could tweak the VX.

Surprise! I really didn’t have to do much tweaking at all to get this modest mount’s RMS guiding error down. I did do a decent polar alignment, and I did spend some time carefully balancing the scope (east heavy with a little declination bias as well). As for the settings, I backed off on a couple of them. Cutting aggressiveness in half and reducing hysteresis as well. Oh, and, conversely, I increased Max Duration both for RA and declination.

The result? Despite OK but hardly great seeing, my errors were immediately halved with me getting just under 1” of RMS error most of the time. Even when my target got low in the sky, and seeing began to deteriorate, the error was just over 1”, easily good enough to yield round stars with an 80mm f/6.9 despite the fairly small (1/2-inch) sensor of the camera I was testing.

While I warned you not to start chasing lower and lower numbers with these GP/CG5 clone mounts merely for the sake of lower numbers, given the small amount of effort involved in this substantial improvement, the few minutes I spent was well worth it.

The other take-aways? People naturally worry about their guide-software settings, but what makes one of the very largest differences? Seeing. Without good seeing you will not see great guiding, so don’t start messing with your settings on an unsteady night. Oh, and good polar alignment is important for good guiding as well. Having to continually chase alignment-caused drift just muddies the water and makes guiding more difficult to get right. Finally, with this class of mounts, correct balance is just as important as polar alignment and seeing. If you want 1” or less guiding errors, you’ll likely need to rebalance if you move to a radically different part of the sky—cross the Meridian, etc.

All those cables!

We’ve spent the last several weeks setting you up with a telescope, mount, camera, and guide system. Now it is finally time to get outside with all that gear (assuming you, unlike me, have clear skies) and use it to capture the deep sky wonders of Spring.

Step One: Set Up

Naturally you’ve got to assemble the telescope and mount. But where should you assemble them? Unless your backyard is really, really horrible light pollution wise, I strongly council you to use the good, old back forty the first couple of times you work with the new gear. You’ll be dealing with a bunch of unfamiliar equipment and some complex tasks, and it’s always easier to do that at home where you can run inside for a look at a manual (or for a quick drink if you get really stressed) under white light rather than squinting at the instructions with a red flashlight at a dark site.

Anyhow, set up tripod and mount and level them. How precise does level need to be for a German equatorial? Technically, you don’t have to level the mount at all. All it needs is to be level enough so that it doesn’t tip over. In some cases, being close to level can make polar alignment easier, however. Level won’t affect polar alignment, period, but being near level means the mount’s altitude and azimuth adjusters won’t interact. When you move in altitude, it doesn’t also affect azimuth, and vice-versa, making it quicker to dial in alignment.

Next, attach the counterweight(s) to the declination shaft. Always mount the weights first, followed by the telescope. You will be mighty unhappy if you do the reverse, your R.A. lock isn’t secure, and the telescope slams into the tripod. When tearing down at the end of the run, reverse that. Remove the telescope first, then the weights. Once the scope is safely on the mount, install everything you’ll be placing on the tube: guide-scope and camera, imaging camera, finders, etc.

Balance is very important if an inexpensive GEM is to track well, so spend enough time with that to get it exactly right. First, decide which side of the Meridian you’ll be imaging on, east or west, and balance accordingly. You’ll always want to be slightly east heavy. If you are going to be imaging on the West side of the Meridian, you should be “scope heavy.” On the east side? “Counterweight heavy.”

Polar alignment with Sharpcap...

Balance in R.A. first. Point the scope north, lock the declination lock and, with the counterweight down and halfway up the shaft (if you don’t know approximately where it should be), undo the R.A. lock at least partway and move the mount in R.A. so the counterweight bar is level. Do not let go of the scope. Now, still without completely letting go, allow the scope or weight to rise or sink. When you’ve determined which way the weight needs to go on the shaft, up or down, return the mount to counterweight down position, lock the R.A. lock and move the counterweight as required. Return the mount to counterweight bar level, and see if balance is perfect. Keep on going with this procedure until it is.

Now for the East heavy bit. When you are in perfect balance, move the weight about ½-inch up the shaft if you are imaging to the west, and ½-inch down the shaft if you are imaging to the east. That should be more than enough to ensure the R.A. gears remain constantly meshed in the interests of good tracking.

For declination balance, return the mount to the counterweight bar level position, lock the R.A. lock and, holding on to the telescope, release the declination lock. When you know which way the scope needs to go in the mount saddle, forward or back, return to the counterweight down position, move the scope (carefully) as required return to the counterweight bar level position, and check. Keep going till the scope is balanced in declination.

What if your mount, like many in this class, is a little stiff on the declination axis and is somewhat difficult to balance? Don’t worry about it too much. Your mount is not tracking in declination, and if you’ve done polar alignment well, PHD shouldn’t have to issue many guide corrections on that axis. Good R.A. balance is far more important; declination balance can be “approximate” without hurting anything.

Step Two: Polar Alignment

If you are using a polar alignment borescope, Polemaster, Sharpcap, or the Kochab’s Clock method, do polar alignment now. None of these methods require the scope to be powered up and tracking, so it’s convenient to do the polar alignment before the mount is all festooned with cables and hand controls (I use Sharpcap these days). Take your time and do as good a polar alignment as you possibly can; you’ll thank me later.

Step Three: Hooking Up

Connecting to the mount...

Plug in all the cables and the telescope’s hand control. You’ll have at least four and maybe five cords to deal with: Power cable, serial cable for scope control, imaging camera USB connection, guide camera USB connection, and an ST-4 cable if you’re going to guide through the mount’s auto-guide port. Try to do a neat job with the cords, arranging them so they are not prone to snagging on the mount or tripod—which will ruin your guiding. Don’t forget to attach dew heater strips, dew heater controller, and dew shield if you need them in your environment.

Step Four: Goto Alignment

Take care of goto alignment now. Do whatever procedure is required to get the mount going to its gotos. How exactly do you line up the alignment stars, though? You can choose one of two methods. You can either remove the camera from the telescope and temporarily replace it with diagonal and eyepiece, or you can use the camera to do the alignment. In the beginning, it may be easier to remove the camera and do the goto alignment with an eyepiece.

If you do use the camera, you’ll, of course, need to turn it on (and the laptop and its software if you are tethering to a PC), and center the alignment stars on the camera’s display or the laptop screen. Since alignment stars are bright, one will allow you to get rough focus, too.

If you choose to use Celestron’s AllStar Polar Alignment, which is built into the hand control firmware, take care of that once goto alignment is done—ASPA requires the goto alignment be accomplished first. If you do a declination drift polar alignment (horrors), now is also the time to do that, since having the telescope tracking during the procedure makes things much easier and is practically required.

Step Five: Focus

The Double Cluster is an easy and pretty target...

If you goto aligned using the DSLR, you’ve got focus roughed in, and can now do a fine focus procedure. If you used an eyepiece instead of the camera, however, get rough focus with the imaging camera at this time. If the last alignment star was a good, bright one, stay on it and use it to focus.

To get in the focus ballpark, adjust the focuser on the telescope (I am a big fan of remote moto-focus for imaging) until the bright star is as small as you can make it and dimmer field stars begin to appear and sharpen. Exposure? I like one to two seconds; that allows me to see results quickly after tweaking focus. Set camera ISO as high as needed to get a good image of the stars. If you are way out of focus, you may need to max ISO out and increase exposure time till you detect the big round globe of a star (in a refractor). Once it is closer to focus, back off on ISO and exposure for a less overexposed star image.

When the field stars are as small as possible by eye, tweak focus with a fine-focus method of choice, which may be a Bahtinov focus mask, or a focusing routine built into imaging software (like Nebulosity) if you are tethering the camera.

Step Six: Acquire Target and Compose Shot

Rough focus done, I interface my planetarium program (Stellarium these says) to the GEM. I start Stellarium (or whatever), and connect it to the telescope mount, that is. How? I invariably use the ASCOM telescope driver system, even if the program on the laptop, like Stellarium, has built-in telescope drivers. Why? Because ASCOM includes a little onscreen telescope HC that allows me to move the mount (at different rates) from the computer. That means I don’t have to get up and walk out to the scope and HC, press a direction button to center the object, walk back to the computer, etc.

A Bahtinov Mask makes fine focusing easy...

Alright, time to get on our first subject. What should that be? Even if you are at least somewhat experienced in deep sky imaging, begin with something easy with this new rig. This time of year, perhaps a nice winter open cluster over in the west like M35 or M37 or the Double Cluster. One important consideration given the economical mounts we’re using? Stay away from the Meridian. These GEMs just don’t track well in that area. Don’t image an object that will come within 10-degrees of the Meridian before your sequence is done, and don’t begin imaging an object until it is at least 10-degrees past the Meridian.

Once the scope goto stops, take an exposure long enough to reveal your target to see how the composition of the shot looks. If the subject is not centered, or just not framed the way I want it, I use the ASCOM HC to fix that. I keep the exposures short enough to make framing easy, maybe referencing a bright star in the frame if the object doesn’t quite show up in 1 – 3-second shots.

What if the target object is not in the field of the camera at all when the goto slew is done? That’s not much of a concern these days for most mounts, but if you have a problem, a quick solution is to slew to a nearby bright star, center it with the aid of your finder and “sync” on it. You should then be able to slew back to the target and have it in the frame. Oh, before you do that, be sure it really isn’t in the frame. If the target is a dimmer one, increase exposure and ISO and see if it appears.

When the subject is properly centered fire up PHD2 and get auto-guiding going. The main gotchas there? Make sure the guide scope is well-focused and that the guide star you’ve chosen is neither too dim nor too bright (saturated). When you put the cursor on a star, PHD2 will tell you all about that. Some imagers believe the guide star should be slightly out of focus for best guiding, but I’ve found I get better results from sharp stars.

When the mount is guiding, I go back to the imaging camera and do a test exposure. How long should that test subframe be? That depends on the sky and the subject. If I’m in the backyard, going much beyond a minute causes the background sky to brighten up so much that processing can be difficult later. At my dark site, I’ll expose for 2 – 5-minutes. Exposure also depends on the subject. An open cluster like M37 will be just fine in 30-second – 1-minute subs. The Horsehead Nebula will not be.

One important thing to remember is that while you’ll be stacking many shorter sub-frames into a finished exposure, you still have to have each individual exposure long enough to pick up all the detail you need. Stacking subframes will make the final result smoother and less noisy, but will not show any detail not present in the individual subframes. Longer subframes are always better.

Get your guiding going on...

What should camera ISO (nee “ASA”) be set to? Normally, use as low a value as you can to capture the detail you want while keeping noise down. The higher the ISO, the noisier the image will be (and the brighter a light polluted background). I rarely go above ISO 1600, and try not to exceed 800 in the backyard if possible. Naturally, ISO and exposure time interact. In general, I’ve found it better to go with a lower ISO and a longer exposure when possible.

Also examine the test exposure for signs of star trailing. Assuming PHD is not going wacky on you, you’ve got a good polar alignment, and the seeing is OK, that should not be a problem at the 400 – 600mm focal lengths we’re using. If the stars don’t look right, go back to PHD and make sure it’s still guiding well (bring up the graph as shown in the image here). If it isn’t, you’ll have to troubleshoot.

If the stars are eggs or worse, first make sure the values you’ve entered for the guiding parameters are close to those we outlined here. One variable that can change from night to night is the guide camera’s exposure. While mounts in this class tend to do best with 1 – 1.5-second guide exposures, if seeing is not good a somewhat longer one can improve guiding. There’ll be less tendency for PHD to try to guide on movement caused by seeing.

Step Seven: Expose

Time to do what we came for, take an exposure sequence. Set the laptop program or the intervalometer to take a number of subframes at the exposure value you determined was best. How many? As many as possible. Even on an easy object like M37, more subs always make for a better looking finished picture. I generally aim for 20 - 30.

Before beginning the sequence, though, let’s put the dark frame question to bed. Since a DSLR’s sensor chip is not cooled, dark frames are mandatory to eliminate the false stars of thermal noise. There are two ways to subtract dark frames from subs, manually or automatically.

If you go manual, finish the imaging run and then, just before packing up for the night, cover the telescope objective and shoot subframes equal in number to the maximum number of lights you’ve taken in a sequence. For example, if you did one 20 and one 30-subframe sequence, take 30-darks. If you used different exposures on different sequences, you’ll have to do more than one sequence of darks—dark frame exposure values need to be the same as their corresponding lights. The darks will be subtracted from the light frames during image processing. This way of working is certainly acceptable, but, in addition to being labor intensive, it isn’t as effective as it could be in my opinion.

Me, I go automatic on dark frames for a couple of reasons. Not only do I not have to worry about messing with darks at the end of the evening or during processing, I think automatic darks are more effective.

How do you do auto dark frames? DSLRs allow you to select a mode called “long exposure noise reduction” (or a similarly named menu item). Engage that, and the camera will take a dark frame after each exposure and automatically subtract it. Yes, that means an imaging run will take twice as long as it otherwise would—30-minutes of subs will take an hour to complete—but I think the results are just better.

Expose!

Why would the results be improved by taking a dark after each light? Because the temperature of the DSLR’s sensor chip will vary throughout the night. Ambient temperature will drop throughout the evening, and, as an exposure sequence goes on, the internal temperature of the camera due to its electronics will tend to rise. To be most effective, a dark should be taken as soon after its matching light subframe as possible, so the temperature it was exposed at is close to that of the light frame.

OK, set that computer or intervalometer for the number of exposures at the required exposure value, push the “go” button and…and…wander around and do something else while the exposure sequence completes. I usually just go inside and watch TV. If I’m at the dark site, I’ll cadge looks through my buddies’ telescopes. I’ll come back periodically and see how things are going—especially how PHD is guiding—but I rarely encounter problems unless clouds have moved in and my guide star has been lost, temporarily or permanently.

Once the sequence is finished, it’s time to go on to the next target. How many targets should you do? That’s for you to decide, but I tend to believe fewer targets, maybe just one or two per evening, and more subframes (and maybe longer exposures) is the way to go.

Done, I’ll pack everything up and head for home if I’m at the dark site, or, if I’m in my secure backyard, I’ll just cover the refractor and GEM with my Telegizmos cover and only take the computer inside—which is a much more pleasant way to end an evening under the stars than having to disassemble everything and carry it back into the house when I’m tired.

And next? Next is processing the images, but that is a story for some other Sunday.

When we last left off with the Novice Files, we’d talked about stars, constellations, and catalogs of stars and deep space objects. This time we’ll be dipping a toe into the somewhat deep water of star charts, “sky maps.” Like that guy standing on the corner in Hollywood hawking his wares says, “You can’t find your way to the stars’ homes without a map.”

Basic Star Charts

You’ve got to have star charts if you’re going to learn how to use star charts. If you want to begin cheaply, I suggest these maps from Sky & Telescope, which cost just a couple of dollars, an equatorial star chart (SC001)and a north circumpolar star chart, SC002 (they have a south circumpolar chart, too). These simple paper maps have been around for decades, will teach you a lot about both the sky and star charts, and will remain useful as long as you do astronomy.

Let’s look at the equatorial star chart first. As the name implies, this chart is centered on the Celestial Equator, the imaginary line in the sky that divides the sky globe into Northern and Southern Celestial Hemispheres. The Equator on this map is the horizontal, triple, hash-marked line that divides the chart in two. Everything above the line is the Northern Celestial Hemisphere, and everything below is the Southern Celestial Hemisphere.

Intersecting the Celestial Equator at two points is a curving, sine-wave-like line. That is the Ecliptic, the apparent path of the Sun through the sky. Why is it curved? As we learned previously, due to the tilt of Earth’s axis the path of the Sun moves north and south in the sky over the course of the year. When the Sun’s path is as far to the North as it goes, we have summer in the Northern Hemisphere. When it is as far to the south as possible, it’s Winter (and summer in the Southern Hemisphere).

You’ll further note that the ecliptic is marked with dates. Those dates represent the position of the Sun at noon on that date with relation to the background stars. On June 1, for example, you’ll find the Sun in the midst of the stars of the constellation Taurus. Finally, the places where the Ecliptic intersects the Equator are the Equinoxes, the Autumnal and Vernal Equinoxes.

A portion of the equatorial chart...

What was the first thing that probably caught your attention on the chart? The stars and constellations. The stars are represented by dots of varying sizes. The bigger the dot, the brighter the star. The range of stars shown on this simple map goes from -2 at the bright end to 6 on the dim end. Actually, while there are a few stars down to magnitude 6 shown, most are left off of this large-scale chart. A magnitude 6 star is the dimmest star most people can see with their naked eye from a reasonably dark site.

How does stellar magnitude work? It’s a logarithmic scale. A magnitude 1 star is 2.5 times dimmer than a magnitude 0 star, and a magnitude 2 star is 2.5 times dimmer than a magnitude 1 star. There are objects, like the planet Venus, the Sun, and the Moon that are brighter than magnitude 0, so there are negative magnitude values as well. Something with a magnitude of -1 is 2.5 times brighter than something that shines at magnitude 0.

You’ll notice that every star on the chart is identified, either by its proper name if it has one, a Greek “Bayer” letter, or a Flamsteed Number, all of which we went over in the last edition of the Files. You’ll also see there are a few deep sky objects scattered amongst the stars, but just a few; mostly the brightest Messier objects. There’s a key at the top of the chart next to the magnitude scale that identifies deep sky object symbols, allowing you to tell if an object is a nebula, galaxy, or star cluster.

But how do you findthings on the map? The same way you do on a terrestrial map, using latitude and longitude. As we learned previously, celestial latitude is declination, and celestial longitude is right ascension. The right ascension scales run across the top and bottom of the chart, showing distances east and west of the Vernal Equinox (located at 0h right ascension), while the declination scales are, naturally, on the right and left, since declination is position north and south of the Celestial Equator.

There are two ways to use the declination and right ascension scales. You can, most of all, use them to locate objects. If you have the right ascension and declination of Sirius, the Dog Star, for example (from a catalog or from a Google search, perhaps), you can easily find the star on the chart.

First, locate Sirius’ right ascension, 6h 45m, on the scale at the top or bottom of the chart (each little tic is 5’). Place an index finger on that. Now find -16-degrees on the right or left dec scales (each tic is one degree). As you’ll recall, a minus declination is a south declination, so you’ll be on the part of the scale below the Celestial Equator. Place your other index finger on -16-degrees. Now, run your two fingers down and across. Where they meet will be, approximately anyway, the location of Sirius.

The circumpolar chart...

The other way to use the scales is to use them to find the declination and right ascension of an object. We see where Sirius is, but what are its coordinates? Place an index finger on Sirius, go straight up or down to the right ascension scale, and you’ll have its R.A. Move your other finger straight left or right to the declination numbers, and you’ll have its dec.

In addition to stars and a few deep sky objects, the chart shows the constellations, the “stick figure” star patterns we introduced a few weeks back. The Sky & Telescope charts use a set of stick figure designs sometimes referred to as “traditional” that are in my opinion the clearest and most easily remembered shapes for the star figures. One question I’m occasionally asked is “What is the right ascension and declination of a constellation?” Since the star patterns cover a fairly large area of the sky, the way you do that is either to use a point in the middle of the stick figure, or to use the constellation’s brightest star as your reference point.

The Circumpolar Chart

While using the declination scale on the equatorial chart, you may have noticed it stops at 60-degrees and -60-degrees, the chart is cut off to the north and south. Why is that? Think back to elementary school. Likely there was a map of the world on the wall, probably a Mercator map, a map using the Mercator projection system. What else might you remember? What I remember is that, weirdly, Greenland was bigger than South America on the map, something I knew wasn’t true.

“Spreading out” the curved surface of the earth onto a flat plane causes distortion north and south. That makes the smallish Greenland huge. If the equatorial star chart continued above 60-degrees north or south, there’d be this same sort of distortion—the far northern and southern constellations would be badly misshapen. The mapmakers here decided to avoid that by placing those constellations on a separate chart, which shows the last 30-degrees before you get to the pole.

Everything in the circumpolar (“around the pole”) chart is the same as on the equatorial chart with two exceptions. The right ascension scale goes around the outer circumference of the chart circle, and the declination scale cuts the map in half. To find right ascension of, say, the bright star at the end of the Big Dipper’s handle, Alkaid, move straight down from it to the periphery of the chart circle, landing on 14h 10m (approximately). Declination is slightly harder to find, but not much. In addition to the declination scale that cuts the circle in half, there are additional unnumbered scales with tick marks. By referencing the one closest to Alkaid, I see it’s one tick down from a major line of declination (each tick is one degree). Referring the labeled scale, I determine the star is at just a bit over 49-degrees north.

There’s one other interesting feature on the circumpolar chart, a big, dashed circle labeled “orbit of the precession of the pole.” What’s that? Well, have you ever played with a child’s top? What happens when it begins to run down? It begins to wobble. The same thing is happening with the Earth. Don’t worry; it isn’t going to fall over, but it is wobbling. Imagine placing a laser beam at the north pole. As the Earth wobbles, the laser will scribe a circle on the sky globe. The point where the laser beam touches the sky globe is, or course, the position of the North Celestial Pole. Precession, the wobble, is slow and it would take 25,765 years for the Celestial Pole to move around the circle one time.

Because of Precession, as the long years roll by, the North Celestial pole moves among the stars. Looking at the circle on the chart, in the distant past, in the days of the ancient Egyptians, the pole was closest to the bright star Thuban in Draco. At that time Thuban was the North Star. In the distant future, the pole will be nearest Vega, and it will be a brilliant pole star. Naturally, the same thing is happening with the South Celestial Pole, and our colleagues to the south will eventually get a good pole star (their current one is relatively dim). Since the pole, 90-degrees declination, is moving against the background stars, the coordinate system and the Equinoxes are being dragged along with it. That’s why star atlases are often identified as “Epoch 2000” or similar. That means that the coordinates in the charts were in the places shown with reference to the stars in the year 2000.

There’s another result of this slow movement over the centuries: it’s put astrology’s Sun signs off by one constellation. Find your birthday on the ecliptic and you may be surprised your “sign” is totally different from what’s given in the newspaper horoscope. According to the astrologers, I am a Cancer, but looking at the ecliptic on the chart shows that on my birthday, July 17, the Sun is actually closer to Gemini. The astrologers set up their Sun Signs many a long year ago and never bothered to change them despite Precession throwing everything increasingly out of whack. Oh, and as you'll see if you look along the path of the ecliptic on the equatorial chart, the band of constellations that lie along it, the Zodiac, includes our old friend Ophiuchus, which the astrologers somehow overlooked.

So, you can find stuff on the equatorial chart now. But it would also be nice to know what was where in the sky for any given time. At first, it’s not immediately obvious how to do that with a chart like this that shows the whole (equatorial) sky, but it’s really simple.

Want to know what’s overhead? Find today’s date on the ecliptic. The constellations that lie long the line of right ascension that passes through that point on the ecliptic are those that are overhead at noon. Unfortunately, it’s not too helpful to know which constellations are overhead at noon. Midnight would be better. That’s easy to do, though. Say the right ascension line overhead at noon is 21h. Count 12 hours of RA to the east (left). That line, 9h, and the stars and constellations along it will be overhead at midnight. If you're interested in what's up at 11 p.m. go 13h to the left, and so on.

Monthly Star Charts

Determining what is "culminating" (straight overhead) for a given time is easy enough with the above system, but it’s not overly convenient. It would be nice to have a chart that shows how the evening sky looks at a given time of year, maybe for the current month. You can get that easily. Sky & Telescope includes an excellent monthly sky chart in each issue. One won’t lead you to tons of deep sky objects, but the brighter ones are marked, and the monthly chart is wonderful when you are just learning the constellations. The Sky & Telescope"annual,"Skywatch, features 12-months of these charts under one cover.

Planispheres

What would be better still? Something, some sort of sky map, that would tell you exactly how the sky looks right now, at the current time and date. Certainly, there are plenty of computerized star charts, “planetarium programs,” that will do that, but we’re not quite ready for them. Instead, let’s begin with a simple analog computer.

You know what an analog computer is, right? Like a slide rule (blank looks from youngsters). A planisphere is a special sort of analog computer that can show how the sky looks for any time or date. It’s very simple—no batteries, no lights, no screen, just a couple of pieces of paper or plastic—but this device has helped generations of amateur astronomers.

A “sky wheel,” as some people call planispheres, is as above in two parts: a round wheel on which the sky is printed, and a stationary piece with a window. Around the sky wheel’s periphery are dates, and around the stationary piece are times. Line up the current time (or the time you are interested in) with the date and the planisphere will show the way the sky is laid out at that time/date.

It gets better. Set the planisphere for the current date/time, go outside, hold it over your head with the arrow or letter on the stationary part that indicates “north” pointed north, so that the west side of the planisphere lines up with actual western horizon and east and south line up with actual eastern and southern horizons, and you’ll be looking at a chart that not only shows what’s where in the sky, but which corresponds to actual directions in the sky.

Using the planisphere to show how the sky looks at a given date and time is one way to use it. There’s another way, though. You can use the planisphere to tell you when some event will occur. When will Orion rise on a given date? Turn the sky wheel so Orion is just above the eastern horizon. Then find the date you are interested in. The time Orion will be in that position will be opposite that date.You can also find the date when Orion will be rising at, say, 10 p.m. Locate 10 p.m. and read the date opposite it. Simple, neat, elegant.

A planisphere is very useful no matter what your level of experience in astronomy, and I always keep one in my accessory box. Where do you get a star wheel? Sky & Telescope sells a nice one. One of the better planispheres I’ve used over the years is made by David Chandler. You can even find them in book stores, including a cool oversize model by my friend David Levy(of Shoemaker – Levy fame, natch).

Are there any gotchas to planispheres? Only a few. In the spring most of us have to move our clocks forward for daylight savings time. While we can move the hands of the clock to suit ourselves, however, we can’t grab the sky and move it forward. That means planispheres always work on standard time. If DST is in effect and you want to know how the sky will look at 9 p.m., you must set the planisphere for 8 p.m.

Looking at the Sky & Telescope planispheres on the webpage, you’ll notice star wheels are sold for specific latitude ranges, 30N, 40N, etc. They are tailored so their northern and southern horizons are at the proper (approximate) declinations. In truth, even if all you can find is a 40-degree one and you live at 30-degrees, or vice versa, that “wrong” planisphere will still be quite usable.

Finally, because the sky on a planisphere is just a map printed on paper or plastic, it can’t depict the planets, which move among the "fixed" stars. That is where computer planetariums come in. And that subject, getting started with computerized charts, will be up next for the vaunted Novice Files. Till then…

Certainly not. The Blog from Chaos Manor South has been rolling along for ten years, and I have every intention of continuing it into the foreseeable future. B-U-T. For a number of reasons, I’m backing away from weekly updates—at least for now.

The Astro Blog actually began considerably more than ten years ago, well before it came to Blogger.com. It was first offered on AOL’s long-gone dark ages blog service, blogger.aol.com. What was it like then? It was short and it came out irregularly. I published when I wanted to, whether that was a week after the previous entry or a month.

It’s been obvious to me for some time that the Blog can’t continue as is on a weekly basis. So, what should I do? Shorten it or publish less frequently?

I’ve demurred on “shorter.” One of the joys of doing a blog is that, unlike in a magazine article, I can stretch out. If a subject needs 3,000 words, it can have 3,000 words. That leaves “less frequently.” How less frequently will it be? I’m considering every other week as a reasonable schedule. But don’t hold me to that. It might be “once a month.” On the other hand, if there’s something I really need to talk over with you, only a week might elapse between entries.

Is this the way things are going to be from here on out, then? Not necessarily. When the current semester ends and I have a whole summer of semi-idleness before me, we could get back to once-a-week. Don’t count on that, but I suppose it could happen. How will you know when the Blog is updated? Follow me on Facebook and/or Twitter.

So, what’s an Uncle Rod True Believer to do on Sunday mornings? If you are new to the flock, there are months and months and months of archived articles for you to peruse. I like to think most of them are as useful and as much fun as they were when they were first published.

Do you find this disturbing? If you do, THANK YOU. It’s been my pleasure to bring this blog to you almost every Sunday year after year, and I am constantly amazed and gratified at how much of a looked-forward-to routine it’s become for many of you. That is reward enough for the labor that has gone into this and is THE reason I intend to continue the Little Old Blog from Possum Swamp.

Spring is here, and with it maybe some clear skies that will encourage you to get out to your club or personal dark site (we’ve had very little rain here, but almost constant clouds). Yes, I constantly preach the worth of the good, old backyard as a spot for deep sky observing, but this is spring, and spring cries out for dark skies.

While some of the bright objects of winter are still on display, if you’re like me you’re focused on the “new” stuff now, the spring wonders on the rise. And what is spring all about deep-sky-wise? Galaxies. The mind-blowing Realm of the Galaxies that stretches from northernmost Coma through southernmost Virgo is back.

Alas, no variety of deep sky object is more harmed by the average suburban sky's light pollution than galaxies . Yes, diffuse nebulae can be tough from the backyard too, but at least a light pollution filter can help some with them. Unfortunately, there is no such thing as a “galaxy filter,” though a few rascals have sold mild LPR filters labeled as such a time of two over the years. The only way to see the marvels of spring as they should be seen is to get to a dark(er) site.

“Dark site? Whatdark site?” How do you find one if you don’t have one? Lots of factors can influence that process. Are you a club member or a lone wolf astronomer? Are you out in the semi-hinterlands where better skies are a short distance from your domicile, or are you stuck in an urban megalopolis? I can give you at least one unvarying piece of advice to begin, however: if you are indeed a lone wolf, join a club. It’s much easier to secure a dark observing location as a group.

“But I’m not really a joiner, Uncle Rod.” That can be fine if you’ve got a close friend with a piece of land out in the dark and that friend is amenable to letting you use it for observing on a regular basis. If you don’t know anybody like that, though, watcha gonna do?

Forget parks, state and national. Most will insist you buy a camping permit and stay overnight if you intend to be onsite past dusk. Even if you are amenable to that (not me; 3 a.m. is my absolute witching hour), few parks have anything that will serve as an observing field. If there is a suitable open space—and there won’t always be one—it will likely be festooned with streetlights. That’s just the way it is—east of the Mississippi anyhow.

As a member of a club, the possibilities increase exponentially. Even if the club you join doesn’t already have a dark observing location—and it likely will—there will be enough people, even in a smaller club, to guarantee a much larger circle possibilities, a larger group of friends and friends of friends with property out in the dark.

If you get down to “friend of a friend of a friend,” in a dark site quest, you’re much more likely to receive permission to use the property if you approach the person as an organized group rather than an individual (“What kind of a nut are you wanting to come on my land at night?”). And a doubtful land owner can sometimes be swayed with the promise of a modest yearly or monthly check from the club.

Let’s say your club doesn’t currently have a dark site, but sure does want one. What sort of spot do you look for? If you’re bereft of anything but the backyard, any dark location will seem like heaven, but, nevertheless, some places are better than others…

Distance

If a site is farther than about 60-miles from the club’s home base, it won’t get used much. As you may have heard tell, it’s often hard to get club members out for observing anyway. My invariable experience is that you can expect maybe 5% of the membership to show up on any given dark of the Moon weekend.

Place your site farther from home than those 60-miles and a maximum 1.5 – 2-hr drive and you probably won't even get the five percenters. You’ll find yourself alone most nights, and you’ll probably stop going frequently yourself after some of the initial fun wears off. 60-miles, however, can work, and is about the distance you need to get from medium-sized and larger cities before sky conditions begin to improve dramatically. See this light pollution mapfor guidance on how far you need to drive from your particular town (and which direction you need to drive in) for good observing.

If you live in a city that’s got a population of less than 250,000 or so, you can fudge on the 60-miles. My own site is about 30-miles to the west of Mobile, Alabama. Yes, there’s a significant light dome to the east, but that short drive ensures our site gets used frequently. There’s often no more than 2 – 3 observers on site on a clear night, but there is always at least that many folks on the field on any nice evening.

Specific Location

Yeah, I know you often can’t afford to be too choosy, but if there are alternatives there are some things it is best to avoid, starting with bad access roads. Yes, the site is nice and dark, but if getting to it requires traversing a rutted dirt track best suited for 4-wheel drive vehicles, and which is a swamp for weeks after a rainstorm, pass the place by if at all possible. Likewise eliminate a site where any part of the drive is difficult, not just to include the final access road. Paved highways leading to the site and gas-stations and/or convenience stores along the route are a practical must.

Before settling on a dark site choice, a few final checks are mandatory. First of all, get out there with a group from the club (whether your dark site committee or just an interested group of observers) and give the place a try. Try to hit the field on an average, not outstanding, night to get an idea what you should expect most of the time. What to look for? What’s the zenith limiting magnitude? Can you see all the stars of the little dipper (if you can, this will likely be a profitable location). Are there any light domes in addition to the one in the direction of the city? If so, is there still enough good sky for productive observing?

How about the field itself? Is it cut regularly? Can it be? This is very important. The site might be OK in the winter, but in the summer with grass three feet high, what are you going to do? Forget leveling your tripod; how are you going to avoid stepping on Mr. Snake? If the property’s owner doesn’t cut it, you’ll either need to induce him to do so with a financial donation or arrange to get it done yourselves if you are leasing the site, either formally or informally.

Are there any/many ambient lights? You may be surprised at how many land owners have multiple security lights. Frankly, due to the growth of the meth trade, the country ain’t what the country used to be. How many lights are there? Can you live with them? If not—especially if you are formally leasing the land—look into providing the offending lights with full cut-off fixtures (with the permission of the owner, of course).

Finally, how are the bugs? Almost any open field anywhere is going to have some bugs at sundown spring – fall. But are the skeeters, midges, no-see-ums, and blackflies worse than normal and can they be dealt with with Off and/or a Thermacell? Often, really bad bug problems can be traced to a nearby farm pond. Before seriously considering a site, check Google Earth to see if there is a stagnant body of water nearby.

Security

We’re conditioned to think “country safe, city scary.” In recent times, however, thanks to the above-mentioned drug explosion in the country, there has been a reversal. There are certainly some unsavory goings-on out in the boondocks these days. How do you pick a safe dark site?

The worst scenario is a piece of land in full view of a frequently traveled road with ungated access and no homeowner/farmhouse nearby. Before passing up on a site like this, check to see what the crime scene is like in the area (if there’s a newspaper covering the county, you can get crime reports there). Talking to people familiar with the area can be highly illuminating.

If you have no other choice than a dubious site and think it’s worth the possible risk, go ahead, but I suggest making it a rule that “nobody observes alone.” Actually, that’s a good maxim even at a secure site. If your vehicle decides it doesn’t want to start a two in the morning, you’ll be glad to have a buddy or two to lend a hand.

Which brings us to the eternal question, “Should you go armed?” I carried a handgun with me to the dark site a few times a couple of decades ago when I was observing alone, but gave that up. I found that if I were so worried that I thought I’d need firepower with me, I’d be too nervous to observe anyway. I just couldn't concentrate on what I was seeing in the eyepiece. After a few minutes I'd begin thinking every snapping twig represented the approach of a psycho killer. When that train of thought began, I learned it was time to just throw in the towel. Far better than a weapon, I found? A couple of fellow observers. Even with just one other person with me, the place went from scary to friendly and familiar.

Always bring a cell phone on observing expeditions. Not necessarily because it will be handy in case of trouble with bad guys, but in case somebody has car trouble that can’t be resolved and needs a tow. Or, worse, someone has a medical emergency. A cell is worth ten times its weight in Walther PPKs.

Maintenance of the Site

Often, if you are formally leasing a piece of land you’ll be expected to take care of its upkeep. Not just to include the above-mentioned grass cutting, but care of the access road. Members’ cars put some deep ruts in it during the damp spring season? It will be up to y’all to get them filled in. It’s best to have a standing club “Dark Site Committee” as a vehicle to get things like this taken care of and paid for.

You’re not leasing a piece of land, just using it thanks to the kindness of the owner? Don’t wear out your welcome. Even if you’re not obligated to get those ruts filled in, do it anyway (or get a check to the owner). As for the site itself, make sure than when the group leaves it is as much as possible in the same condition as when you arrived. No trash, no cigarette butts, etc. If the owner’s home is nearby, keep the hee-hawing down in the middle of the night. Yeah, know that meteor was pretty, but don’t holler “GOOD ONE!” at the top of your lungs at two a.m.

Visitor Control

Yes, it’s OK to invite a prospective club member to the dark site, but… Make it clear that that is a one-time good deal and that regular access to the club dark site requires a paid membership (and possibly an additional dark site fee to cover site maintenance). If you don’t, the word will eventually get out, and you’ll have people you don’t know and don’t know anything about showing up at your observing field.

Finally…

Enjoy observing from a safe, secure, and dark location! How do you best do that? That’s a story for next time.

Last ish we got you a dark site, or at least gave a few pointers as to how you and your fellow astronomy club members couldfind and keep one. This time, we’re going to talk about using that site.

And you know you want to use it. Sure, in this day of electronic cameras and computer processing you can take pretty good pictures from the backyard, but you’ll always get better results under dark skies. Visual observer? As I said last week, the galaxies of spring cry out for the darkest skies possible.

There is no doubt about one thing, spring weather in the USA, and especially east of the Mississippi, can be capricious. Before talking about what you bring to your club’s observing field and what you do there, maybe we should discuss “whether.”

Obviously, if you’ve got beautiful blue skies and the forecast is for more, a dark site trip is a natural. But what if the sky is unsettled and the weather forecasts ambiguous? Back in the day, back when I was more sanguine about hard-core observing, back when I lived downtown and couldn’t observe anything from my backyard, I had a rule, “If it ain’t raining, head to the dark site.”

That stood me in good stead for years, and resulted in me seeing far more than I would have if I’d let a few clouds scare me off. Most of the time—though certainly not all of the time—I at least saw something at the club site in return for an hour’s journey into the west. I would sometimes wimp-out observing plan and gear-wise, though. If the sky really did look doubtful, I’d tend to change my plans from “astrophotography” to “visual,” and the telescope from my C11 to my 5-inch ETX Maksutov Cassegrain, Charity Hope Valentine. Anyway, I always found that even if I was mostly skunked, I had a better out on the observing field than I would have had sitting at home watching television.

Let’s say, you’ve got a night that looks to be uncompromisingly good, though. What do you load into your vehicle? The simple answer is “everything you need, nothing you don’t.” Certainly you want all the gear you require to allow you to execute whatever your observing plan is, but there are things you’d take to a multi-night star party that you will likely want to leave at home for a club site run. Remember, you’re going to have to pack all that stuff back into your car at the end of the evening and possibly unload it at home.

What NOT to Bring to a Dark Site…

Observing table

You may actually need an observing table depending on your vehicle and what you are doing, but maybe you can back off from a big camp table to a TV tray. If I am doing visual observing, a table just large enough for an eyepiece box and maybe a star atlas is more than enough. Imaging? I’ll need something to put the laptop computer on, but not anything more than that.

When I switched vehicles from a sedan (a Camry) to a truck/SUV (4Runner), I eliminated observing tables altogether, operating out of the back of the 4Runner, tailgating it as it were, which is the best of all worlds—I even have AC power available there from the truck’s built in inverter and auxiliary battery.

Computer

This is a maybe/maybe not thing. Even if you are doing imaging, you may be able to eliminate the laptop. Using a standalone auto-guider and a digital single lens reflex (saving images on the camera’s memory card) can allow that. By saying “ixnay” to the laptop, you can also leave one large battery at home (a laptop’s internal battery will rarely last an entire observing run), the above mentioned table, cables, mouse, mousepad, etc., etc., etc. Yes, it’s nice to have a computerized star atlas like Stellarium, but in the interests of simplicity, sometimes I don’t mind getting reacquainted with Sky Atlas 2000 or Uranometria. Just can't go back to that? SkySafari running on a tablet is a good compromise.

Stuff you always bring and never use

You tend to throw a pair of binoculars in the car, but never/rarely use them? Leave them at home. The same goes for stuff like extra flashlights, a second box of eyepieces, radios, ice-chests, etc. All that junk is nice at a big star party, but you are not going to be at the dark site long enough to feel the need for this stuff.

A telescope that is just too much

Small can be beautiful...

We all want to maximize our observing experience, but if a telescope is so large and/or complex, that by the time you get it assembled and working it’s time to go home, leave it at home. Give me a freaking C8 for dark site use not a C11 or (horrors) C14. When all your buddies are packed up and ready to hit the road and you still don’t have the scope off its mount, I think you’ll begin to believe that sacrificing some aperture and/or features might not be such a bad idea.

Things that will annoy your fellow observers and possibly the landowner

Radios blasting your particular preference in music and green laser pointers that make the sky look like something out of Return of the Jedi have no more place at the club dark site than they do at a big, organized star party.

What to Bring

A Telescope

Sure, you know to pack the telescope, but make sure you pack all of it. One night, one cloudy night, when it wasn’t raining, nevertheless, I headed to the dark site with my C11. As soon as I arrived onsite, almost magically the clouds began to scurry off and I began assembling my big scope. Yes, as above, it was really too much for a short dark site run, but I was younger, stronger, and dumber then.

I had just got the NexStar 11 GPS on her tripod when I had a vision. Of the telescope’s hand control sitting on the dining room table of Chaos Manor South. And that was just where I’d left it. What to do? There wasn’t anything to do. I packed up and went home. I was just thankful I wasn’t at a star party 400 miles away.

In the interests of this sort of thing not happening to you, it’s a good idea to have a checklist. If you know an item is necessary, put it on the list and don’t check it off till it is packed in the car.

Power

A telescope that doesn't need batteries can be nice sometimes...

Some lucky folks have AC power available at the club site, but that is rare. Be prepared to operate off batteries all night. So, ensure your batteries are fully charged beforehand. Don’t just assume they are. What sort of batteries? I favor the ubiquitous 17ah jump start battery packs. Not only do they have enough juice to power most scopes and accessories all night, they usually have built in lights which are handy when you are packing up at the end of the evening. Yes, don’t take too much stuff, but don’t scrimp on batteries. I always take one for the (goto) scope, one for the dew heaters, and one for the laptop.

Dew Heaters

At home, in my backyard, I can often get by without a dew heater system on my SCTs and refractors. My house and neighboring houses and trees shield much of the heat sucking sky from the view of my scope, acting as giant dew shields. On an open field out in the country? Uh-uh. Even if your area is drier than my Gulf Coast stomping grounds, you’ll need something to keep dew off.

Dew prevention is a subject for an entire article, but I can offer some basic guidance here: use heater strips on objective or corrector. If all you have is a dew-zapper gun—a 12 vdc hair drier cum window defroster—you will soon lose the battle against dew. A zapper can be sufficient for the secondary mirror of a Newtonian reflector, however.

Observing Chair

You’d think this would be something I’d tell you to leave at home, but it isn’t. Even for a relatively short visual observing run, being comfortable means you will see a lot more. Bring the chair along.

Accessories

Use that checklist to make sure you bring the vitals: eyepieces, star diagonals, star charts (or a smart phone or tablet), red flashlights, etc. Don’t overdo. I restrict myself to one eyepiece case and one accessory box (a large Plano tacklebox).

Insect Repellent

"If it ain't raining." Sometimes you eat the bear, and sometimes...

Whether “just” a can of Deep Woods Off, or a Thermacell, don’t even think about heading to the dark site without bug zappers except in the very depths of winter.

A Coat/Jacket

“But Uncle Rod, it’s only gonna get down to the lower 70s.” Bring a coat or sweater or sweatshirt anyway. You will never be colder than when standing nearly stock still at a telescope under an open sky. Let it get to the mid-60s and you will begin to shiver and will throw in the towel unless you are prepared.

Cell phone

Don’t just always bring your cell phone with you as we insisted last time, make sure it is fully charged before leaving home. Taking a DC charger to the site might not be a bad idea either.

A Few Amenities

You won’t be out there that long, so don’t pack too much additional stuff, but certainly a few bottles of water and maybe even a couple of snack items is “reasonable.”

Setting Up

It’s your dark site, set up anywhere you like, right? Sure. But some places are better than others. If there’s been a recent rain, you’ll be better off on your field's high ground if it has any. You probably don’t want to be on a slope, however; telescopes are happiest on level ground. One other thing? Togetherness is fine. You want to be close to your buddies so you can share observations, chat, etc. However, if you’ve only got a few people at the site there’s no need to set up 3-feet from the next scope. Spread out and give each other some room.

Observing

You observe the way your normally observe at home or at a star party. What I’m really talking about here is observing rules. Your club probably needs to come up with a few. You want to prohibit white light and probably green lasers. But you don’t want to keep adding so many rules that people feel stifled. And be aware that at a club site with two or three people on the field, all those beloved rules formulated at that marathon club business meeting are likely gonna be observed in casual fashion at best.

For example? You wouldn’t dare fire up your vehicle and drive off a star party field at midnight, but at the old dark site with a few people around? It’s likely to be, “Had a great night Wilbur! See you next time, Hiram! Gotta head on home.” If everybody’s observing visually they can shield their eyes while you motor off. If someone’s in the middle of an astrographic exposure, wait until they are done. Just use common sense—and the same goes regarding any rules you and your mates think up.

Packing Up

The Moon is rising, or it’s just late, or it’s just you and your friends’ usual turns-into-a-pumpkin time. What about tear-down of the equipment? If, as above, you have to leave earlier than your pals, you’ll need to pack by red light (one of those red LED head-lights on a head-band is good if you keep it pointed at the ground).

You'll soon tire of using a dew-zapper gun...

Anyway, when the time comes, disassemble your scope, taking care that everything gets back into the vehicle. I tend to be a little less than scrupulous about putting every widget back in its proper place in the cases; I just shovel it all into the car so as not to delay my friends, and worry about sorting everything out the next morning (I can leave all my stuff in my car overnight thanks to a safe and secure neighborhood).

Once everything is back in the car, go over your area carefully with a white light to make sure nothing got dropped and that you’re not leaving any trash behind. Help your fellows out with the same thing. Then—well, you’re off for home (or perhaps your favorite late night bar out in the boondocks).

You’re off if everybody is ready to go, that is. One rule our club has made and that we observe scrupulously is, “Nobody leaves till everybody leaves.” Obviously that doesn’t apply to someone who has to go early for whatever reason. It just means those of us left at the end of the night linger on till the last person has their gear packed. That’s good for security’s sake, but even if, like us, you have a very safe dark site it’s still a good rule to live by. What if the last person standing has trouble getting their vehicle started?

Then, just say your goodbyes, “Great time, y’all! See you next time.” If you did everything right, and your club has the “right” site, believe me, you’ll hardly be able to wait for next time.

When I’m speaking about the history of Schmidt Cassegrains at star parties, club meetings, or cons, I often get puzzled looks and questions from new amateurs about one of the things I say: “One of the big reasons for the 8-inch SCTs becoming the most popular commercial telescope in the 70s was astrophotography.” What? Everybody knows SCTs aren’t good for taking long exposure deep sky pictures. For that you need a short focal length refractor, right?

Maybe and maybe not. Firstly, back in the 70s when the Schmidt Cassegrain began its rise to fame, the other common telescope alternatives for deep sky astrophotography were the cumbersome, shaky Newtonians practically everybody owned, and refractors with focal ratios of f/15 or more. Take it from someone who was there, it was a million times easier to take deep sky astrophotos with a C8 than one of those telescopes.

Also, while I won’t disagree that for beginners in astrophotography, a refractor of short focal length is easier to manage in the beginning, we don’t remain beginners forever. Eventually you may discover more focal length, aperture, and resolution than what your 80 – 100mm refractor offers can be a good thing. So what are the problems with using the average Celestron C8 or Meade 8-inch for deep sky imaging?

The first gremlin is simply all that focal length. With a C8, you start out with a native focal length of about 2000mm. That is what, more than anything else, makes long exposures tough with the telescope. At 2000mm, every tracking faux pas your mount commits will be exaggerated. Not as stable as it ought to be? A tiny gust of wind will ruin your picture by creating trailed stars no matter how well you guided. That may make anything but the shortest exposures problematical in autumn and winter when the winds are wont to blow.

Also, if you’re a plebe like me, you won’t be using a 10 thousand dollar mount for your telescope and will have to guide it. You’ll use a small auxiliary camera to keep the telescope precisely centered on the target despite the inevitable back and forth motion of periodic error caused by less than perfect gears. At 2000mm, you will have to guide precisely. How precise depends on the pixel size and sensor chip size of the imaging camera, but you can bet there won’t be much room for error.

Then there are the mirror flop blues. To focus, the primary mirror of a Celestron or Meade SCT slides up and down on the baffle tube that protrudes from the main mirror. The mechanical tolerances there are OK for visual use, but are loose enough that the mirror can move slightly when the attitude of the telescope changes significantly—as when crossing the Meridian. Result? Those darned trailed stars if you’re using a separate guide telescope for auto-guiding the mount. To the guide camera, everything looked fine, but the image moved in the main camera when the mirror flopped.

An imaging rig back in the day!

None of these things present insuperable difficulties, though. After all, me and my mates were using C8s to take good pictures—which I define as pictures that made us happy—thirty and forty years ago. We didn’t have electronic cameras, either. We manually guided our telescopes and usually exposed for a minimum of half an hour even on bright objects and with “fast” film in our SLRs. If we could get decent shots with a Schmidt Cassegrain then, certainly you can now.

Again, I don’t endorse a C8 or Meade 8 as your first astrographic telescope. Cut your teeth on the vaunted fast ED refractor—they are cheap now and come as close to being foolproof for deep sky imaging as you can get. But when you are ready to move up in focal length and aperture, however, begin collecting the astro-stuff you will need…

Get a Modern SCT

Get an Edge (Celestron) or an ACF (Meade). Their better field edge performance is a good thing, no doubt about that, especially if you also intend to use the scope visually. Admittedly, unless you are employing a camera with a full frame 35mm sensor, you won’t notice the difference in images, but you might as well invest for the future so that if/when you move to a bigger chip you’ll be ready.

The really big deal with modern SCTs for imagers is not necessarily the field edge, but that they have mirror locks. The Celestron Edges have them, and so do the 8-inch Meade ACF telescopes. These locks stabilize the primary mirror and prevent it from flopping if you are guiding with a separate guide scope.

Get a Focal Reducer

All the Meade and Celestron 8-inch SCTs come in at f/10, that 2000mm we talked about above. Not only does that many millimeters make guiding and tracking more difficult, it makes for longer exposures and can be a challenge for accurate goto pointing. The solution? If you get the Celestron, buy the Edge f/7 reducer. If a Meade, the standard Meade f/6.3 reducer corrector (the Celestron 6.3 works fine on Meade scopes too). The Meade and Celestron 6.3 reducers are reducer correctors, designed to flatten the field edge of non-ACF telescopes, but they work just fine with ACFs since most of their effect is to, yes, flatten the field rather than remove coma—which the ACFs’ optical system does itself.

A 66mm f/7 makes a nice guider...

How about other focal reducers? Like those from Optek? They can be a good choice if you’ve got a Meade scope, but some can’t be used visually. Those for the Edge scopes definitely can’t. Only the Celestron f/7 Edge reducer can be used for that. Since you’ll probably want to eyeball the heavens your Edge SCT once in a while, get a reducer that will work with an eyepiece.

Get a Good Enough Mount

This is the most important thing if you’re considering SCT astrophotography: how good is the mount’s tracking? Especially with a payload consisting of an 8-inch SCT, camera, and guide scope (which may be upwards of 30 pounds). It doesn’t matter if you image with a fork mount or a German equatorial—both have their pluses—it just matters that you get good tracking with a tricked out 8-inch SCT onboard.

Can you get by with the fork mount that came with your telescope? Maybe, if it’s of fairly recent vintage. Older forks can be a crapshoot. I once encountered a Meade LX200 GPS with 90” of periodic error (that’s a lot). Modern forks like the CPC Deluxe from Celestron and the fancy LX600 from Meade are certainly much better for imaging than the old ones. HOWEVER, thousands of good long exposure images have been taken with the minimalist AC driven fork mounts of the 70s and 80s. Use what you have, but a good mount makes things easier.

For most of us, a good mount is a GEM. A German equatorial has the advantage of allowing you to use a variety of scopes on the mount. You can do widefield with a refractor without the hassle of trying to piggyback it on a fork mount’s SCT OTA. One is also more portable than a fork mount, though an 8-inch fork SCT isn’t too much of a hassle for most of us to transport and set up.

How much should you spend on a mount? That’s up to you. Prices for GEMs usable for imaging with an 8-inch Schmidt Cassegrain range from about 800 dollars all the way up to 10 thousand dollars and more. Before spending oodles of cash, though, ask yourself how often you are really going to be able to or want to take pictures. For most of us that is maybe once or twice a month--IF the weather cooperates.

Me? Thanks to our stormy Gulf Coast, I rarely do astrophotography even once a month. For me, an inexpensive imported GEM is more realistic than a top of the line AP, Bisque, or 10Micron. Keep the sub-frame exposures down to 5-minutes for less and an Atlas or a CGEM can work very well with an 8-inch SCT. Given my usual conditions, it’s not like I’m going to be taking 12-hour exposure sequences anyhow.

Off-axis guider...

Don't scrimp on the mount, though. While I’ve taken OK images with my C8 and a CG5 or AVX GEM, it was clear thesemounts were at their limits with the telescope. And so are the other GEMs in this class up to and including the HEQ-5 (Sirius). For ease and reasonable consistency of results, consider the next step up, the EQ-6 (Atlas) or CGEM or CGX mounts. If your skies and your skills are better than mine, and you are less lazy than me, I wouldn’t criticize you for bumping the mount choice up to a Losmandy G11 (about 4K), but you don’t have to do that to shoot good deep sky astrophotos with a C8. An Atlas type mount will do it.

Get a Sufficient Guide Scope

Today’s sensitive, high resolution guide cameras don’t require the crazy long focal length guide-scopes we used in the day of manual guiding. Still, you need a guide scope (a refractor or a reflector that does not use a moving primary mirror to focus) with enough resolution so the guide camera can “see” small errors when imaging with an SCT.

I am lazy and get along with one of those 50mm finder-guide-scopes that are so popular now, but I suggest a minimum of 400mm of focal length for the guide telescope when doing C8 astrophotography. A Short Tube 80 or similar will do as long as you can lock the focuser down securely. And you have a sturdy mounting for the 80. That is incredibly important when imaging at these focal lengths, since the smallest amount of flexure in the guide scope rings will show up as trailed stars in the main scope’s images.

Get an Off-axis Guider

Well, maybe. I suggest you try a guide scope first and only if you find you just cannot get the gremlins out of your guiding setup no matter how you tighten things down or tweak the Brain settings in PHD2, should you consider an off-axis guider.

An “OAG” allows you to both guide and image through the main scope. One contains a little “pickoff” prism that diverts a small amount of the light at the edge of the telescope’s field to the guide camera. Since it is seeing the same images as the main scope, problems like flexure and mirror flop instantly disappear.

Unfortunately, there’s a price to be paid. The OAG will only pick up stars around the periphery of the telescope’s field. There may be few of the them, and their shapes may be distorted if you are using an older “standard” SCT whose field edge is not perfect. In this day of sensitive guide cameras, the problem of finding a suitable guide star is not as bad as it used to be, but it can still be difficult. I used an OAG all through the film days, but never found it to be a pleasant experience.

Get a Good Polar Alignment

Declination drift due to poor polar alignment just makes the task of guiding more difficult. Strive to get within a couple of minutes of the celestial pole if possible. That used to be tough, but innovations like the Polemaster polar alignment camera, and the polar alignment routine in Sharpcap (which uses the guide scope and camera to do the alignment) have made it positively easy.

Tips for Getting it all to Work

Balance

C8 Edge plus Atlas EQ-6: not quite perfect but mine...

With a sub-Losmandy mount, a Chinese GEM up to and including the iOptrons, be scrupulous about balance. That means balancing the mount so it is slightly east-heavy. Of course, you will likely have to rebalance if you move far from your initial target. That is not a big problem for most of us, since we’ll usually only image one or two objects a night and it’s easy enough to pick two subjects in roughly the same part of the sky. “East heavy” can make a big difference in how an imported mount performs, since it ensures the R.A. gears are always properly engaged.

Keep Subs Short, but…

With a C8 riding on an AVX or similar mount, you may find it to your advantage to keep individual exposures short. To pehaps a minute or two. If you have a bad spot on your gears, just throw out that sub-exposure and be on to the next one. Over an exposure of 5 – 10-minutes, there’s a lot that can go wrong with a light mount’s tracking ruining that whole, long shot.

Do remember, though, that sub-exposures have to be long enough to capture desired detail. While stacking subframes will make a shot less noisy and smoother, no detail not visible in a single sub-frame will show up in the final, stacked, photograph.

Keep Working with PHD Settings

I didn’t for the longest time and am now sorry I didn’t. The settings I had were good enough for the APO refractors I usually use for imaging these days, yielding RMS guide errors of 2” or a bit more on my AVX and CGEM. Couple that with my laissez faire approach to polar alignment, and most of my shots with a C8 (reduced) didn’t have perfectly round stars if I zoomed in enough in Photoshop or whatever.

Eventually, I decided I needed to do something about my guiding, since I wanted to begin imaging with the Edge C8 again once in a while. I read up on the PHD2 Brain settings and devoted one entire evening to tinkering with them. In just that one night my RMS guide errors went from 2” to 3” to a bit more than 1” at best, and under 2” at worst. That, coupled with Sharpcap polar alignment, has meant that for me imaging with the C8 is easier than it ever has been.

Shoot Appropriate Targets

If a target, a medium-small galaxy or globular cluster, perhaps, cries out of an 8-inch SCT, by all means use one as the imaging scope. If it doesn’t? Use a nice 3 – 4 – 5-inch ED refractor instead. Why make things hard on yourself for no good reason? In addition to less focal length, a refractor in this range will be lighter than the SCT, and an inexpensive GEM mount will always track better with a lighter load.

And that is that. Don’t be afraid to try long exposure deep sky astrophotography with an 8-inch SCT, no matter what you may have read on the darned Cloudy Nights BBS. A little experience and you may find it’s not as difficult as you'd been led to assume, and that the focal length and aperture of your friendly, neighborhood C8 or M8 brings a new dimension to your astrophotography.

As you may know, for years I was one of the leading proponents of the Schmidt Cassegrain Telescope (SCT), and am one of only two people to have ever written a (commercially published) book about the telescopes. In fact, I am the only author to have published two books about Schmidt CATs. Heck, for the better part of two decades many of you knew me as “Mr. SCT.”

In the last few years, however, I’ve made it no secret that I’ve somewhat turned away from SCTs and to refractors for a variety of reasons. What gives? Am I now fer ‘em or agin’ ‘em? Answer? It’s complicated.

In fact, just about everything concerning the SCT is complicated except for its relatively simple design (other than that dratted corrector). Moreso than any other telescope it raises strong emotions. It doesn’t just have fans and skeptics, it has lovers and enemies. It’s unusual to see a general discussion of the SCT online on BBSes like Cloudy Nights that doesn’t degenerate into slings and arrows from both sides.

That being so, I thought this Sunday we’d go over the arguments of both the prosecution and defense in the Curious Case of the SCT: Is it a Good Telescope or Not?

For the Defense:

The SCT is Portable

The Schmidt Cassegrain is just naturally easy to transport and set up given its folded optics and short tube. The C8 packs two meters of focal length into an OTA less than two feet long. Carrying around and mounting an 8-inch f/10 Newtonian is something of a nightmare, but an 8-inch f/10 SCT is practically a grab ‘n go scope, to summon that overused cliché.

A modern fork mount model is virtually a self-contained observatory. Not only is there goto, computerized pointing, to the tune of tens of thousands of objects, some models now feature built in auto-guiding, wi-fi, and can align themselves with little user intervention. An 8-inch SCT, a battery, maybe a DSLR, a box of eyepieces and you are ready for either visual or imaging work at the drop of a hat.

These Telescopes are Supremely Affordable

The most amazing thing about SCTs? They’ve gotten cheaper. Back in the day, in 1995, I paid over two-thousand dollars for my Ultima 8 SCT. It was a nice enough telescope with very good—if not perfect—optics and a sturdy fork mount and tripod. However, there was no goto or other computerization. The mount was powered by a 9-volt battery. Turn it on and the telescope tracked, turn it off and it stopped. It did have a Periodic Error Correction (PEC) feature, but when you turned the scope off at the end of the night, your hard-won PEC “recording” was lost and you had to re-do PEC all over again the next evening. Otherwise? There wasn’t even an auto-guide port.

Me and my new Ultima 8 circa 1995...

Today, 1500 bucks in our decidedly smaller dollars will get you a Meade LX90, a very competent SCT with a sturdy-enough mount and tripod and a hand control with zillions of objects. If you can bump the budget up to 2700 George Washingtons, you can have an LX200 GPS, a telescope that doesn’t just include just about every conceivable computer feature, but which has a mount at least comparable to that of my old Ultima’s massive fork. Oh, and the LX has a much better-looking field edge than the Ultima 8’s thanks to the telescope’s ACF, “Advanced Coma Free” optics. While I haven’t done the computation, the LX200’s current price is still likely less in real dollars than what I paid for that manual telescope in '95.

Meade and Celestron’s Optics are Excellent Now

I’m not just talking about the dreaded Halley-scopes, the SCTs produced during the comet Halley craze, when I say Schmidt Cassegrain optics could be variable in the past. There were some excellent ones, but there were also some dogs. The good news is that both companies are very consistent today. There may be fewer stand-out scopes, but there are also far fewer poor ones. Add to that advances like Celestron’s Edge optics which reduce coma and field curvature, and Meade’s ACF optics, which reduce coma (and which are available in f/8), and it’s no exaggeration to say that in general terms SCT optics are better than they ever were.

The SCT is Well-suited for a Variety of Tasks

Thanks to features like the moving mirror focusing system dreamt up by the man who invented the commercial SCT in the 1960s, Celestron’s founder Tom Johnson, few telescopes are so suited to such a wide variety of tasks. You can take high resolution pictures of Jupiter one night, observe deep sky objects the next, and do spectroscopy of distant galaxies the evening after that.

It’s not just that the moving mirror focusing gives the SCT tremendous a back focus range that will accommodate eyepieces, cameras, and other sensors of all types, it’s that it has become the PC or telescopes. The SCT has been around in commercial form for over 50 years, and both companies have more or less retained the standards Celestron implemented in the 70s. A visual back from the mid-1980s will still screw on to any modern Meade or Celestron SCT. That means there’s a huge number of accessories and add-ons for these scopes.

Those many accessories include focal reducers and extenders (Barlows), and thanks to the Schmidt Cassegrain’s focus range, it’s easy to make these things work on the telescope for visual or imaging use. Most SCTs are natively f/10 telescopes, but just a few dollars gets you extenders and reducers that give you an f/20 and an f/6.3 too. It’s like having three telescopes for the price of one.

The Schmidt CAT is Usually on the Cutting Edge of Technology

When some new innovation is developed, it’s usually developed for SCTs first. When goto came to commercial amateur scopes, it came in the form of the Celestron Compustar and Meade LX200 SCTs first. If you want the latest and the greatest—like Meade’s Starlock System, which provides integrated guiding and goto—look for it in Schmidt Cassegrains and especially fork-mount SCTs first. Why? In part because Meade and Celestron SCTs are still the most popular commercial telescope. The numbers keep the prices down despite ever increasing (electronic) features. An impetus to this innovation is the fact that you’ve got two companies competing for one small market. It’s like Honda and Toyota—the two keep innovating and adding more features in hopes of pulling ahead of the competition.

High-tech observing in the 90s...

For the Prosecution…

The Schmidt Cassegrain May be Transportable, but it isn’t always Portable

Certainly, smaller SCTs are quite portable, but not quite as portable as they’re often said to be. If you don’t mind carrying a telescope out in at least two pieces and assembling it, a 5 to 8-inch SCT is portable. However, even A C5 stretches the idea of grab ‘n go. Oh, some people might pick one up in one piece and waltz it into the backyard, but it’s more of a handful than you’d think. Most Fork mount C8s? Few of us would want to carry one more than a few feet. A fully assembled C8 on a GEM, even on one of the relatively light CG5/VX/Exos size mounts? No way, not unless you are the incredible Hulk.

Get above 8-inches, especially with fork mount models, and even “transportable” becomes dicey. A 10 – 12-inch fork SCT OTA/fork/drivebase will weigh in at around 50 to 70 pounds. Even when setting up in alt-azimuth mode, more than a few people will be challenged. You’ll have to lift that awkward tube/fork/drivebase combo onto a tripod at least waist high and get it oriented on and bolted to said tripod. Onto a wedge’s tilt-plate for use in equatorial mode? At the 10-inch level that is sometimes a job for two, and at 11 and 12-inches it most assuredly is. The biggest CATs, the 14s and 16s, are telescopes for permanent or semi-permanent installations where you can at least wheel scope out of storage and onto an observing pad.

How about a GEM, then? A 10-inch isn’t bad. At 11-inches, however, many normal adults will be stressed. It’s not so much the weight as it is the awkward bulk that has to be held steady as the dovetail is slid into or tipped into the mount’s saddle. A 12-inch is entering the realm of scary for most, and a 14-inch—which is like wrestling with a full garbage can—is a daunting task. Mounting a 16-inch is a serious undertaking for at least two men.

SCTs in smaller sizes aretransportable and convenient, but as aperture increases, they become surprisingly less portable than some other designs. Today there are 20-inch (ultra-light) Dobsonians that are farmore portable than a 12-inch LX200.

These Telescopes are Affordable, but You Do Get What You Pay for

There is no denying Meade and Celestron Schmidt Cassegrains are supremely affordable considering their apertures and features, but there is a reason they are cheap. While both companies have thousands of satisfied customers, the road to satisfaction is sometimes a rocky one. One of the reasons SCTs are inexpensive is that they are made and sold in (relatively) large numbers. Another, more concerning, reason is the Chinese companies’ QA programs are not exactly robust. Even scarier is that some of the materials and parts used in these telescopes are of lower quality than they should be.

Me and the bigun...

A case in point was Meade’s much heralded RCX400. The one I used (loaned me by a Meade rep at a star party) worked well and had some amazing features. I did note the fit and finish was rather poor even for a mass produced SCT, especially given its 4000 dollar plus price tag. Internally, it turned out, the story was even worse. Many of the telescopes arrived DOA, often thanks to the inexpensive motors Meade used in the focusing and collimation system—and that was just the tip of the iceberg.

While the RCX is an extreme example, the same sort of thing, the same low-balling of parts and lax QA, is evident all across Meade's and Celestron’s product lines. Wise advice? Don’t be an early adopter of one of the companies’ scopes. While both do tend to get their products right, it often takes a while—that “while” extending even to “years.” If you get a DOA SCT and have to ship it back to your dealer or the maker, or if your scope develops continuing problems, it may not seem like such a bargain after all.

Meade and Celestron Optics are Pretty Good Now, but are Still a Compromise

Both companies have come a long way since the 1980s and early 1990s when it comes to optical quality. And, certainly, credit where credit is due for them introducing improved designs like the Edge and ACF. However, SCT optics with their 30% range central obstructions will always be a compromise. Their contrast characteristics are never going to be as good as those of unobstructed or minimally obstructed scopes. Also, thanks to their mass-produced nature, these days you will likely get good optics but you will rarely—if ever—get great optics. Surprisingly, both companies produce great refractor optics and often excellent MCT optics. It seems SCTs are just a little more difficult to get to that level, and it appears they always will be.

The Schmidt CAT is a Jack of All Trades, but Master of None

The SCT is indeed good at many things, but there are often other designs that are better at any one of those things. If you are an astro-dilettante like Uncle Rod, that may not matter, but if you have a special interest area in our avocation, it might. A Newtonian or a refractor, for example, is a better instrument for planetary observing. A large and portable Dobsonian is better for visual deep sky work. A refractor, an APO refractor, is arguably a better choice for deep sky astrophotography (although an SCT can certainly shine when it comes to imaging small DSOs or planets).

Sometimes We’d be Better Off Without All the High-Tech Gimmickry

Even "just" a C11 is a handful...

Being able to control focus and collimate the telescope with the hand control sounded great when the RCX400 was announced, but, as above, it didn’t work out to anyone’s satisfaction. Given the price arena Meade and Celestron play in, sometimes the tech just won’t work right given the money M&C have to develop and implement it. Goto on both brands is pretty rock solid now, but, still, sometimes simpler is better, or more dependable anyway.

The Verdict?

That is up to you. I’ll let you make up your minds about it and would love to hear your decisions in the comments section. Me? These days I am perhaps not quite the Schmidt Cassegrain evangelical I once was, but I still use them. My stable may have shrunk to a single C8 (my Edge 800) and a C11 (whose days may be numbered), but, yeah, I still use ‘em.

When I do pull my C8, Emma Peel, out of her case, it’s like coming home. I know, Mr. Wolfe said you can’t go home again, and that is somewhat true. I am more aware of the design’s warts than I used to be (or would admit), but I still believe “right tool for the right job,” and that right tool is still sometimes the good old Schmidt Cassegrain.

One of my traditions is that each year, sometime over the course of the summer, I take a picture of star cluster Messier 13. Why? Well, it’s tradition as Tevye said. But it also ensures I get out at least once during the hot, humid, hazy, and usually stormy Gulf Coast summer and take a few deep sky pictures.

I’ll admit these days I am not sanguine about braving sweat and mosquito bites trying to get images from skies that look like milk. If I lay off until fall, however, I get out of practice. And as complex an endeavor as deep sky astrophotography is, you do not want to get out of practice.

Usually, I do my portrait of the Great Globular in Hercules from my dark site in the wilds of northwestern Mobile County. Not this year. With June already segueing into July and hurricane season threatening to get started in earnest, I thought I’d better get my M as soon as possible. The conditions were just lousy, though. So lousy that I had no intention of loading a ton of gear and driving half an hour to the dark site only to sit under clouds hoping for sucker holes while providing dinner for hordes of six-legged fiends. The good, old, backyard it would be.

Can you get decent photos of deep sky objects from the backyard? Yes, you can, and not just of the brighter objects, either. You’ll notice in the shots here that M13’s little “companion,” the near 12^thmagnitude galaxy NGC 6207, shows up readily and even gives up its nebulous disk. M13 itself and similar bright clusters are really no challenge. But whether you’re trying easy or hard from the back forty, what will lead to success is the understanding that imaging the deep sky from brighter skies is a battle.

This battle is between the target object and the bright background. While it is much easier to pull a washed-out object out of the light pollution today with electronic cameras and digital processing, it’s still best to minimize light pollution induced background brightness to the extent you can.

Pac Man Nebula with "Imaging" LPR filter...

One thing you can do to accomplish that is use a relatively slow telescope. Why? Have you ever tried a wide-field image from light pollution? If you have, you know it’s pretty hopeless. After little more than a minute—or maybe even less—the image appears to be of the daytime sky. Most (fixed focal length) camera lenses are so fast, f/2 or faster, that the background blows out in a hurry, before many details in the object you are wanting to image are recorded. So, slow it down. I like f/6 or, better, f/7 from the backyard.

How about filters? I’ve tried them, mild “imaging” LPR (light pollution reduction) filters, and it’s a mixed bag. I do find them helpful in capturing fainter nebulae. A filter allowed me to get a respectable image of the Pac Man Nebula from my yard on a not so good evening. There is a penalty, however—color shift. While the nebula was easy enough to color balance, when it was just right the stars were a distinct reddish hue due to the presence of the filter. On the other hand, I was able to get a better picture of the Pacmeister by far with than without the filter. I use a filter only when there is no alternative.

In the interest of keeping the background glow a little lower and not burning out—overexposing—the cores of globulars and similar objects with bright centers, I generally set my DSLR’s ISO no higher than 800. That is more than adequate to bring home faint nebulosity, and in addition to keeping the background less overpowering, it reduces the noise in my frames. Stacked ISO 800 frames are visibly less noisy than stacked ISO 1600 ones.

The big question, though? How long should your subframe exposures be and how many should you take? The latter is easy to answer: “As many as possible.” Each additional subframe added to a stack decreases noise and makes processing easier. Certainly, you shouldn’t keep exposing when the object reaches problem areas like the Meridian (for some mounts) and the horizon (for all mounts). But the more good subs you can get the better the results will be. Don’t be shy about throwing out poor subframes, of course—ones with trailed stars or aircraft or satellite intrusions. If you take lots of subs, it won’t be as painful if you have to delete a few.

How long should the individual exposures be? That’s harder. Longer exposures pick up more details and are less noisy than shorter ones. Remember, no matter how many frames you stack, no details not present in a single subframe will be visible in the finished, stacked image. So, the basic requisite is that you must expose long enough for desired details to be visible in individual frames.

In a 1-minute exposure the background is brown...

At a dark site, go as long as necessary, or as long as you and your mount can stand it exposure wise. In the backyard, though, you will be limited. Expose for much over a minute or two and the sky background will become incredibly bright and color shifted as in the picture below, a two-sub 300 second exposure with my f/7 120mm ED refractor, Celestron AVX mount, and Canon 400D. Processing can bring back a passable final result, especially when it comes to darkening the background, but fixing the light pollution caused color shift is a more serious and difficult problem.

As you can see in my final 300-second x two subs picture in the comparison shot below, M13 is noticeably (too) blue. I got the background unreddened using the “background color offset” function in Nebulosity, but that left M13 with a cool tinge. That can be fixed as well, but it takes more work and more skill.

While the 300-second sub picture shows more stars, frankly I think the 60-second x 10 image actually looks better. 60-seconds isn’t long, no, but NGC 6207 is just as visible in the shorter sub-stack. It was also much easier to process with a less bright background and not as much color shift (the background was more on the order of brown than red).

Conclusion? In a light polluted backyard, shorter, more numerous subs are often better, or at least easier to process, than longer subs no matter how many longer subs you take. What your exposure limit should be depends on the degree of light pollution and the current sky conditions.

For me, 300-seconds is a good subframe exposure on a dark(er), dry winter night when I have a zenith limiting magnitude of 5.0 or so. On a spring or summer evening when humidity scatters light pollution, 1 – 2-minute subs are what I do. On this summer’s night, ten 60-second subs were definitely preferable two two 300-second subs. And more 60-second subs would have been better still. So why did I stop with ten? Ah, on that hangs the short tale of this annum’s M13…

300-seconds and the background is a bright pink-red...

As July came in, the question became not “When will I get M13?” but “Will I get M13 at all?” There had been precious few opportunities to take deep sky pictures all spring long. And not that many this past winter, either. Summer was thus far shaping up to be as bad if not worse. So, when Accuweather’s Astronomy Forecast on the web and my Scope Nights and Clear Sky Chart apps on the iPhone began to look slightly favorable, I got my rig set up in the backyard tout suite despite temperatures climbing well past 90 (try “feels like 101F”) and high humidity.

Said rig? My SkyWatcher 120ED refractor, Miss Hermione Granger, Celestron AVX GEM, and old Canon 400D. Why was I using the lighter mount rather than the Celestron CGEM? I was a wimp. An astro-wimp. I couldn’t face the prospect of lugging the 40-pound plus CGEM head out into the backyard in the heat.

By the time I finished cabling up everything—camera to computer, mount to computer, guide scope to computer, shutter control cable to camera, dew heater, mount power cord, hand control, etc., etc. etc.—I was wet with sweat and just this side of being overheated. Seeing as how it doesn’t get dark till way past 8:30 in these days of daylight savings time, however, I had sufficient time to cool off before starting the run.

When the stars finally began to wink on, I got the VX polar aligned. As I mentioned some time ago, I no longer use Celestron’s All Star Polar Alignment routine (in the hand control) to do my polar align. I find Sharpcap’s polar alignment tool, which uses the guide scope and guide camera is easier and more effective. My declination error with a Sharpcappolar alignment is noticeably lower than it ever was with ASPA, even given two ASPA iterations.

60x10 (top) and 300 x 2 (bottom)...

That out of the way, I used Celestron’s StarSense camera to do the mount's goto alignment, sent the scope to Vega so I could focus up, powered on the camera and, at the PC, started Stellarium and StellariumScope, PHD2 Guiding, and Nebulosity (my camera control program; I always tether my DSLR to the laptop). Focusing was a snap with a Bahtinov maskand the full screen display furnished by Nebulosity. I went on to Neb’s fine-focus tool, too, and noted that seeing was OK but not great, surprising for a humid summer night. Focus done, I sent the mount to M13, centering the cluster in 2-second exposures using ASCOM’s little onscreen HC.

When I was satisfied with my composition, I switched to PHD2 and got its guiding calibration out of the way, clicking on a bright, but not too bright field star. PHD2 calibrated readily, and when that was done began guiding. I always give the auto-guiding a few minutes to settle down, and, so, walked back inside to enjoy the cool for a few minutes. Returning outside, looking at PHD2 revealed the RMS guiding was about 1.5” or lower, more than good enough for my 900mm focal length refractor and APS-C size chip. That being the case, I returned to Nebulosity, and instructed it to take 25 60-second exposures.

A great thing about Nebulosity and PHD2? They are rock solid. If I wanted, I could have just sat inside and let them do their thing without me. I got bored with channel surfing however, and returned to the laptop on the deck before long. PHD2 was guiding great, and the frames coming up on Nebulosity looked good. I noted little NGC 6207 immediately. All was well. Until...

Just as I began to wonder whether I should go back to the den and see if there were something good on Netflix, my iPhone just about gave me a heart attack with its alert tone. The issue? “A line of severe thunderstorms is headed your way.” Rut-roh, Raggy! Looking to the west, I realized that what I’d thought was distant fireworks was actually lightning.

Hmmm. Should I wait and see? I’d only accumulated ten subframes so far. Unfortunately, the phone insisted the weather would arrive by 11:45, and it was already past 11:30. Deciding discretion was the better part of valor, I turned off the AVX, covered Hermione and the mount with my Telegizmos cover (recommended), disconnected the computer, and scurried inside.

I was a little miffed, but back in the blessedly cool den, I realized that out in the heat and humidity I had begun to get dehydrated without realizing it, so mesmerized by PHD2’s tracking graph I had been. I re-hydrated with a Gatorade and called it a night. I was tired enough that I didn’t even deign to look at the year’s M13 on the laptop.

My yearly M13 2017...

Next morning, I stacked and processed my shots—which I thought were pretty pleasing and far from the worst annual M13 I’ve ever done—and strategized about the coming night. The storm had come and the storm had gone, so I would be able to get out for a second summer night in a row (!) it seemed.

What would I do? I had two things to accomplish. First, I wanted to take some longer subs of M13, 300-second subs, for the comparison above. I also wanted to do a little experimenting with the PEC function on the AVX, something I had not previously gotten around to despite having owned the mount for four freaking years.

And so, I hit the backyard once again. My experience with PEC and long(er) subs on the AVX? That, my friends, is a subject for nextweek.

Me and my trusty Ultima 8 PEC circa 1995...

If you read the last installment of the good old Astro Blog, you know I am a proponent of shorter (60 – 120-second) sub-frame exposures for astrophotography. When appropriate. Like from a light polluted site. There are times when you want to go longer, to 300-second or 600-second or longer sub-frames, however. Say when you are at your dark site and want to pick up as many details in the target object as possible.

Some of you, especially cheapskates like me who use inexpensive mounts like my Celestron Advanced VX German equatorial mount (GEM), are afraid of longer exposures. How can you break the 300-second barrier without getting trailed stars? There are ways to do that fairly easily. Good polar alignment is one. Spending time tweaking the settings in your auto-guide program is another. One other thing that is often overlooked and unused, but which can maybe get you the last step on the road to longer subs, is PEC.

Yeah, PEC, aka “PPEC.” You know what that is doncha? You don’t? Well, PEC, “periodic error correction,” was an idea that came out of the early 1990s, when microprocessors and memory chips not only came down in price, but began to appear in telescopes. I don’t know who originally came up with the idea, but it was a good one.

In those days, we amateurs were still guiding manually. You’d monitor a guide star in the guide scope or off axis guider with a cross-hair reticle eyepiece. When the star wandered away from the center due to the inevitable “periodic” errors in the mount’s gears, or drifted north or south due to polar alignment error, you pushed a button on the hand control (which we still called a hand “paddle”) to move that pesky star back to the cross-hairs. You did this over the duration of a long deep sky photographic exposure, which in the days of film was likely at least half an hour.

The good idea represented by PEC was this: What if there were a way to record your button pushes? Record your corrections for that periodic error and play them back? That would, if nothing else, make guiding easier. Thanks to the recurring—periodic—nature of the gear error in worm gear sets, which is what most of us were using by then, it sounded like PEC could indeed work.

Again, I am not sure who came up with the PEC idea, but the first people to implement it in a commercial telescope were Celestron, the old American based (though Swiss owned) Celestron out of Torrance, California. They brought PEC to the market initially with their top of the line C8 Schmidt Cassegrain, the Ultima 8, in a new version of the telescope, the Ultima 8 PEC.

It just so happened that not long after the final and best version of that telescope was released, the 9-volt battery powered Ultima 8 (PEC), I was in the market for a slightly upscale SCT. Well, as upscale as penny-pinching me ever goes. By the spring of 1995, I finally had an Ultima of my own, and after buying a few rather expensive (I thought) accessories like a declination drive motor (optional in those days) and a counterweight and rail for this fork mount scope, I undertook to do some deep sky imaging. I was curious to see if PEC really took the pain out of guiding.

Phd2 guiding graph: VX with auto-guiding + PPEC...

What I found was that it helped. You certainly could not expect to go unguided with the C8 at 1500mm (at f/6.3) for over a minute or two—not long enough to accomplish much with film—but it did make guiding less arduous. You still had to watch the guide star, but if you did a good PEC recording, you would usually be OK if you looked away from the reticle for a moment or your attention wandered. The periodic error was still there, but its magnitude was lessened.

Celestron’s PEC implementation was certainly not the end of manual guiding. Naturally, it only recorded your east-west corrections. Any errors in declination are not periodic; they are due to polar alignment error or seeing, not periodic error. Too bad I was always rather lazy about polar alignment in those days. That meant I still had to monitor the guide star attentively.

Also, Celestron’s version of PEC left a little to be desired. Mainly because you had to do a brand-new recording every single night. It was a shame you couldn’t save an especially good PEC track for future use. Turn off the scope at the end of the evening, and your PEC recording disappeared into the ozone.

Nevertheless, I used PEC to the end of the film days, and it did improve my photos, no doubt about that. But when electronic cameras and auto-guiding came in, I forgot all about PEC. Yes, there had been improvements in it—Meade and, finally, Celestron had equipped their mounts with PPEC, permanent periodic error correction. With PPEC, your recording was preserved through power cycles. But why worry with PEC since you had a guide camera and a computer watching that guide star now?

There was also an old wives’ tale making the rounds. That PEC and an auto-guider would FIGHT each other. That the auto guider and PEC would conflict, one wanting to correct this much and the other that much; one wanting to go in this direction, and the other in that. Some of those old wives were pretty sharp, but this particular tale doesn’t really make a heck of a lot of sense when you think about it. Nevertheless, for a while it was the conventional wisdom astrophotographers embraced. I just sort of accepted it—when I thought about PPEC at all, which was seldom. I was auto-guiding and that always seemed to be enough.

M13: 300-seconds at 900mm f/l...

Well, I thought it was enough, anyway. Auto-guiding with my Advanced VX GEM with my QHY-5L II camera and PHD2 resulted in an RMS error around 2” usually. That was good enough for my most used telescopes, my 80mm and 120mm f/7 ED refractors and my DSLRs. There were some occasional R.A. spikes, though, and at times the error would climb above 2”.

What could I do to improve on that error figure? One thing I’d avoided doing since buying the VX: spending some time fine-tuning those blasted PHD2 brain settings, the settings in the program that modify the guiding algorithm. I’d pretty much left them on their defaults other than just increasing the guide-step size to accommodate my fast 50mm guide scope.

So, I finally buckled down and took one whole night where I did absolutely nothing but tweak PHD settings. The result? My guiding was now smoother. The spikes were gone, and I rarely had an error above 2”; usually it was 1.5” or just a bit more. The elimination of the spikes meant I could now do longer exposures without having to throw out more than a few subs.

And then I got to thinking. Why should I stop there? If I could get that error just a little lower, it would make imaging with my Edge 800 (at f/7) easier. But how to do that? I’d worked hard on those PHD settings, and had also begun using Sharpcap’s polar alignment tool in lieu of the less accurate ASPA polar alignment in the NexStar HC—that really brought the declination error down.

What else could I do, though? Well, how about PPEC? If it helped A-P’s fancy mounts, which come with factory recorded PPEC to lower their already impressive error figures, why couldn’t it help my plebian (like me) mount?

I decided to find out. Luckily, we were undergoing a strangely cloud-free pause in the usual summer evening thunderstorms. My VX along with my 120mm SkyWatcher ED refractor, Hermione, was still set up in the backyard, polar aligned, goto aligned (hibernated), and ready to rock following the night of my Yearly M13. Since the evening didn’t look that good for imaging—haze and also unsteady seeing in advance of the next storm front—why not devote it to PEC? After all, I’d spent a whole evening getting my PHD2 settings tuned to the VX.

OK, so how exactly would I make a latter-day PEC recording? I’d taken a brief look at the short set of instructions in the VX manual and concluded there really wasn’t much to it. The process wasn’t much different from back in the day except for the fact that PHD2 Guiding would be doing the “button pushing” and not me (thank God). Since I guide via the mount’s auto-guide port with an ST-4 cable, the set up was simple. No need to worry about ASCOM or anything like that.

While the book instructs you to use a bright star for guiding when PEC recording, there’s no reason for that with today’s sensitive guide cameras. I pointed the scope at the field of M57 and there were dozens of good guide star candidates. Some folks will also tell you that for best PEC results you need to make the recording using a star near the Celestial Equator. That is also untrue. It really doesn’t make any difference.

Step one, it appeared, was “indexing,” allowing the mount’s PEC routine to find the worm gear “index,” a marked point on the worm that is picked up by a sensor. For PEC to work, the hand control has to match the gear to the recording every time you use PEC, the gear and the recording must be synchronized. Indexing does that. Anyhow, I selected PEC in the Utility menu, and hit enter. The mount then indexed, which only took a second or two (if the worm has to rotate far to bring the index mark to the sensor, the mount will move slightly). Time to record.

Over at the PC, I started PHD2 guiding on my pre-selected guide star. I gave it a little while to settle down, returned to the mount, and hit “record.” That began the ten-minute process of making the actual PPEC recording. Unlike the old days, there wasn’t anything for me to do. Assured PHD2 was guiding with its usual alacrity, I headed for the den to cool off from the hot and muggy backyard.

M57: 600-seconds...

The rest was rather anti-climactic. I returned outside ten minutes later, and could see from the HC that the recording was done. Just like with a tape recorder, you don’t just record, you play back. I selected the playback function and let her rip, beginning a 600 second exposure of M57 with the main camera, my Canon 400D.

What were the results? Error wise, they weren’t like night and day, but there was a difference. As above, my normal error level with good PHD2 settings and a good polar alignment had been around 1.5”. With PEC playback on, the RMS R.A. and declination error declined to around 1” to about 1.10” with the actual R.A. error almost always well under 1”. While I was slightly out of focus with the main telescope, the stars in the ten-minute exposure were decently round, as were the stars in a 300” exposure of M13 despite the fact that it had crossed the Meridian and the mount was not balanced properly in R.A. for imaging in the west. My verdict? Recording PEC had been nearly effortless and certainly worth it for a noticeable improvement.

Over the last several months, my easy improvements: PHD settings, polar alignment, and PEC have taken my AVX mount from an average total guiding error of 2 – 2.5” to 1”. While I was getting by before, I am certainly doing better now. And the fact that my guiding is now consistently smooth with no excursions mean I am much, much more able to undertake longer exposures, 300-seconds and above, when appropriate. My sense is that as long as balance is reasonable, the mount will guide at the above error level for as long as I want to go.

So, am I at the end of my improvements? Maybe, and maybe not. I could certainly leave the AVX alone now. But there is one further “easy” improvement I could essay. My single PEC recording improved the error figure. But averaging several runs and uploading that resulting smoothed curve to the mount might make it even better.

Celestron still offers a free program to do that, “Pec Tool” (even though it hasn’t been updated or publicized in a long time). I may be reaching the point of diminishing returns with the VX—1” RMS error is pretty good for a mount in this class—but it might be worthwhile to take this one last step. I’ll let you know how it goes if I decide to do that (ain’t broke/don’t fix it) and if clear skies ever return this summer. It is, yes, raining hard now.

Actually, I could have called this issue “Lo, There Shall be an Ending”—Part II. If you’ve read the linked post, you know that for a number of reasons I been thinning out my telescope and mount herd. I got rid of a bunch of stuff in the weeks following that article’s posting, and I thought I was in a good spot, finally, with astronomy gear I could and woulduse. Well, you know what they say about “Best Laid Plans,” doncha?

I liked my Celestron CGEMmount a lot. It had been a good performer, guiding well and not exhibiting any of the problems some of these Celestron GEMs—mostly earlier examples—have been heir to. Then trouble began. Actually, this trouble started a year before I bought the CGEM.

I took a fall at Chaos Manor South one afternoon not long after we moved out three years ago. The details? Let’s just say it was a boneheaded stunt. I fell on my back and right onto the concrete front steps of the Old Manse. Ouch! right? But while I was bruised and sore, I thought I’d dodged a bullet—until last summer.

Summer of 2016 bought a spate of back problems that just wouldn’t quit. Until theydid rather abruptly a month or so after their inception. I was again fine until the beginning of this summer. The latest installment of My Aching Back began following an afternoon when I set up the CGEM in the backyard, lifting the 40-pound plus mount head onto its tripod.

The next morning my back pain returned—big-time—and I was pretty sure what had caused it. I'd been careful lifting the CGEM, I thought, but apparently not careful enough, and again went through weeks of suffering. End result? I won’t say I’m scared of setting up the CGEM…but… OK, I’ll say it: I am scared to do that. I haven’t used the mount in months and don’t believe I’m going to use it much ever again without some outstandingly good reason—something far beyond just wanting to take deep sky snapshots.

It seemed to me, then, that it was time for, yes, “Lo There Shall be an Ending: Part 2.”. The CGEM will have to be sold, I’m afraid. I also still have my nine-year-old Atlas EQ-6, which I’ve been holding onto as a backup for the CGEM. It is only a little lighter than the Celestron mount, so I’ve reluctantly decided it must depart as well. Alas, the same goes for my beloved carbon fiber tube C11, which I am also hesitant to wrestle with now.

Don’t despair for me, however. I intend to replace the two mounts with a single lighter one with comparable or higher payload capacity—maybe a Losmandy GM-811G or an iOptron CEM60. Mounts that will accommodate my Edge 800 better for imaging than my Celestron Advanced VX mount can, but which I won’t be afraid of lifting. It does require me to spend more money on the replacement than I spent on either the CGEM or Atlas, but even penny-pinching me is ready to dole out money for a mount that will accommodate my heaviest scopes, but that I need not fear using now or in the coming years.

M15 with C8 + Atlas EQ-6...

Lighter weight but as much (or usually more) payload capacity is the payoff when you go to the next mount price tier above the CGEM and EQ-6. I’m not saying those Synta-made mounts aren’t an incredible value—they are—but increased weight is the penalty for both respectable payload capacities and low prices.

While I’d used the CGEM early this summer, I hadn’t done anything with the Atlas for a couple of years, not since the Peach State Star Gaze of 2015. I was their Keynote Speaker that year, and because of the event’s relative closeness in Georgia I was willing to drive up rather than have them fly me in. So, I was able to take the EQ-6 and a couple of telescopes with me. The mount performed well, but that was then. I didn’t want to sell Atlas to someone without giving him a through checkout, which I began doing one recent and somewhat cloud-free night.

I decided to recount my process of setting up, aligning, and interfacing the Atlas EQ-6 here, since I thought that might be instructive for those of you considering buying one or who are new to the SynScan mounts—the Atlas EQ-6, the Sirius HEQ-5, and their sisters—sold under the Orion and SkyWatcher brand names.

The first thing you gotta do if you wanna play telescopes with an Atlas is get the big equatorial head onto the tripod. Following my debacle with the CGEM earlier this year, you can bet your freaking bippy I was cautious. I carried the head to the tripod, which I’d already assembled, leveled, and oriented with its azimuth alignment peg north, in a plastic case with two good handles (from Walmart, natch). I was awfully, awfully careful to lift with my legs, not my back, when I pulled the mount out of the shallow box.

How bad was it? I didn’t like doing it, but I didn’t strain anything. The mount is actually a little easier to get on the tripod than the CGEM in my opinion. Something about its shape seems easier to hold onto. Also, its counterweight bar, which is slightly slimmer than that of the CGEM, can be retracted into the mount, and I found doing so made the head less awkward to lift.

M33 with William Optics 80 Fluorite + Atlas EQ-6...

With the R.A. lock locked securely to keep the mount from flopping around, I hoisted the head onto the tripod, aligning the peg on the tripod with the azimuth adjuster assembly on the mount, lowered the GEM head onto the tripod and secured it with the tripod’s threaded bolt (I leave that slightly loose till polar alignment is done).

Mount safe on tripod, I proceeded to do the usual set up things: Extend counterweight bar and load one Synta 11-pound “pancake” counterweight on it—all that is needed for my 5-inch refractor. Place telescope in the Atlas’ Vixen style saddle and secure it with two lock bolts. Attach hand control and power cords, taking care to thread the power cord through the mount’s strain relief widget.

Taking care to dress and secure the power cord is important. The Synta power cables are notorious for losing their connections, the earlier cables, anyway. As on the CGEM, the power receptacle rotates with the Atlas’ RA axis, and the cord tends to become loose or even disconnected. That is the reason Celestron (Synta) used a power receptacle with a threaded collar on the CGEM when that re-design of the EQ-6 was undertaken. The latest EQ-6es, the EQ-6 Rs, also have that feature.

After balancing the telescope in RA and declination (it’s best to have the EQ-6 very slightly east heavy in RA for best tracking during photography, but that is not as critical as it is with mounts in the CG5 class), comes a fairly important operation, setting the mount to home position.

The EQ-6 has neither position switches nor alignment marks, so it is up to you to place the mount accurately in “home” position. That is necessary to allow the mount (which has no encoders; it just counts stepper motor steps) to know where it starts from. Technically, I suppose, after you accurately goto align the mount, how good or bad your home position setting was should no longer matter. It should just help the mount land near the initial alignment star. Nevertheless, at times it sure seems that the more care I take with setting home position, the more accurate my gotos are. Go figure.

Home position for the EQ-6 is with the telescope pointed north and the counterweight bar straight down. It’s easy to achieve this accurately using a small carpenter’s level. Set the mount to 90-degrees in RA with the counterweight bar on the left and the scope on the right as viewed standing behind the mount. Use the level to get the counterweight bar as level as possible. When that is done, lock the RA lock, loosen the RA circle, and set it to “6” using the scale appropriate for your hemisphere; the upper one is for the Northern Hemisphere.

Ready for testing!

Next take care of declination. With the mount still positioned with the counterweight bar level, undo the declination lock and level the tube. Then, set the declination setting circle to the value shown on the mount’s latitude (elevation scale). I am at 30 degrees latitude, so my elevation scale is on 30, and I set the declination circle to thirty degrees.

Now to actually set home position. Undo the RA lock and move the mount in that axis until the RA setting circle reads zero. Then, do the same for declination: unlock it and move the scope in declination until it reads zero, too. If you did everything correctly, the mount should be in accurate home position with the counterweight bar down and the tube pointing due north. After a couple of times, this procedure will become second nature.

Next up is polar alignment. Unlike with the Celestron branded mounts, the accuracy of polar alignment affects the accuracy of gotos, so try to do a good job. I use the Sharpcap program’s polar alignment tool to get a dead-on polar alignment, but the EQ-6’s included polar scope can do OK. You should go beyond the simple “match the constellations” polar alignment outlined in the manual, however. See this articlefor a simple to do but more effective method of polar borescope alignment.

Can’t see Polaris? The SynScan hand control now includes an AllStar Polar Alignment Procedure in the Align menu (it will not show up until you complete the goto alignment). See the manual for details. I understand this procedure can yield an alignment at least as good as a careful polar scope alignment, just like ASPA on the Celestron branded mounts. I have not used it enough to be able to testify to its accuracy, however.

With my mount in home position and polar aligned, it was time to do the goto alignment. Once you get past time, date, location, etc. in the hand control, it will ask if you want to proceed to alignment. You do, but the question then becomes “Which alignment?” since you have three main options, One Star, Two Star, and Three Star.

One Star: You line up one measly star and hit enter. Choose this option if your mount is well polar aligned and you’ll be working in a relatively small area of the sky. Near the alignment star, you’ll get good gotos, and they should be OK, at least, on the same side of the Meridian as the alignment star. On the other side of the Meridian, your goto quality will likely decrease. It may also suffer toward the horizons and at large distances from the alignment star, even on the same side of the Meridian as that star.

Two Star: Use a two-star alignment, centering two alignment stars, if you want to range a little more widely afield in the sky. Gotos should be good everywhere, assuming the telescope doesn’t display a lot of cone error, that is, its optical axis is pretty much in line with the mount’s polar axis.

EQMOD with settings screen...

If your scope does have some cone error? Well, you can try shimming it in the saddle to eliminate that, but a Three Star alignment is an easier go, I guess. In this method, you center an additional star, a third star, which will be on the opposite side of the Meridian from the other two.

So, there I was out in the backyard wanting to give old Atlas a clean bill of health. Since I have often used a Schmidt Cassegrain on this mount, I am accustomed to doing a Three-Star. Even if the tube itself doesn’t display much cone error, mirror flop due to the SCTs moving mirror focusing system can introduce some error anyway. However… I wasn’t really in the mood for a Three Star on this evening.

The day had started out hot, humid, and partly cloudy. By nightfall it was just about as hot, even more cloudy, and seemed stickier and more humid than ever. Despite the presence of my Thermacell bug repeller, the mosquitoes were threatening to carry me off. I wanted to be done and done quick. A One-Star it would be. Frankly, I often use this alignment method anyway. I most often employ the Atlas for imaging, and usually only do one or two targets a night—typically targets in the same general area of the sky. A One Star alignment on a nearby bright star is all I need.

Alrighty then. I told the SynScan I wanted to align, and selected One Star. I then scrolled through the available stars until I got to Vega, selected it, and, after the slew stopped (Vega was in the finder but not the main eyepiece), I centered the star using the up and right keys—just like with a Celestron—which is what you’re instructed to do with current SynScan firmware.

My results after the HC declared “Alignment Successful”? What was in the immediate area? There was M13. I punched that in, hit enter a couple of times, and the mount slewed that way. When it stopped and beeped, there was a little fuzz spot dead center in the field. Now, this was a 40mm (Plössl) eyepiece, mind you, but one with a fairly narrow AFOV, so there wasn’t a whole lot of true field. Also, I’d done the One Star with this eyepiece rather than with a high-power reticle ocular (recommended) because I was lazy. All things considered, that was pretty impressive goto-accuracy, I thought.

After M13, I decided to see what the mount would do on the other side of the sky. Arcturus was in the eyepiece, but off toward the field edge. So was Mizar. That was just what I’d expected. Back in the eastern half of the heavens, M57 was dead center. So was M13 once more, when I decided to take one last look at it before adjourning to the cool den.

EQMOD connection with USB EQDIR cable...

Any other goto alignment tips? Try to adhere to the “rules” for alignment star choice given in the manual. Especially the one that says that stars one and two in a two or three-star alignment should be at least 3 hours of right ascension apart (that is, separated by 45 angular degrees east-west if at all possible). The current SynScan firmware does a better job of picking alignment stars than it used to, but keep these rules in mind. Try not to use a star near the horizon or the zenith, for sure.

Still getting gotos that are “off”? Try PAE, “Pointing Accuracy Enhancement.” See the SynScan controller manual for details, but this allow you to enter multiple additional alignment points all across the sky. I don’t often use PAE, since my telescope and camera combos give wide enough fields that the mount doesn’t usually miss if I’ve been careful with setup and alignment, but I have found it to come in handy a time or two.

Anyhow, fairly assured the Atlas was still in good working order, I parked it, covered mount and scope with my Telegizmos cover, and headed for the blessed coolness of the house. I wasn’t completely done, though. Next, I wanted to test the mount with a laptop, sending it on gotos with Stellarium and StellariumScope. But that was a task for another evening. I was covered in sweat, suffering from a summer cold, and despite my success with the Atlas was just this side of “out of sorts.”

As the Sun sank on evening two of the EQ-6 check-ride, the sky was not looking good, not good at all. Not completely cloudy, no, but hazy with large swathes of thin clouds slowly drifting through. Still, I figured it would be good enough for stage 2, making sure the mount would still goto its gotos under control by a laptop computer.

One thing I wanted to try in that regard was the new SkyWatcher ASCOM driver. Previously, I’d used a Celestron driver for the EQ-6. That worked fine, no problem, but recently, with the advent of the new Celestron unified driver, support for the Celestron scopes had been discontinued, I had been told. I could simply have used an older Celestron driver, but I wanted to see how the SkyWatcher one worked.

EQMOD's normal display...

With my Scopestuff SynScan serial cable plugged into the base of the hand control and the other into my KeySpan USB-Serial converter, I proceeded to fire up the Stellarium/StellariumScope combo, which is about all I use to control my goto scopes these days. Hokay, selected the new SkyWatcher driver, hit Connect, and immediately got a warning about my hand control. Said text informed me that the driver wouldn’t work with a version 2 HC, needing at least a Version 3 or 4. Rut-roh.

I was puzzled since I dohave a version 3 HC. It doesn’t have the very latest firmware loaded, no. It is at v3.37 instead of the current 3.38, but that is still pretty recent. After I dismissed the warning window, however, everything seemed normal. I was sitting on Vega, and the onscreen scope crosshairs were on Vega as well. I clicked on M13, hit the CTRL + 1 key combo Stellarium uses to initiate gotos, and the mount responded immediately, moving the scope right to M13. The big star-ball, nearly centered in a 13mm Plössl at 75x, actually looked better than I thought it would in the yucky sky.

The same was true of any object I requested. I even let the scope track unattended for a half hour or so to see if the driver would crash, but it didn’t. Verdict? Warning or no warning, the driver worked well.

I took another gander at M13 and a peep at M92, and, as I was pondering whether there was anything else that would look good on such a putrid night, the sky well and truly closed down with a big thud. I covered scope and mount and left the mosquitoes to fend for themselves.

The next morning, I investigated the driver issue further. It turned out that what it was trying to tell me was that I did indeed need SynScan firmware version 3.38 for full operability. I’m not sure which features of the driver might not work with 3.37—goto was fine which is all I care about. At any rate, I am a big fan of “if it ain’t broke, don’t fix it,” and believe I will leave it to the mount’s next owner to decide whether to upgrade the HC to 3.38.

Only one major thing remained on my testing agenda. There’s computer control, and then there is EQMOD. If you’ve got or have been considering buying a SynScan mount I’m sure you’ve heard of that, but what it is is a special ASCOM driver. It doesn’t just send goto commands to the mount, it replacesthe SynScan hand controller—much the same as the NexRemote program replaces Celestron’s NexStar HC. I began using EQMOD with the mount not long after I purchased the Atlas in November of 2007, and its capabilities have always impressed me.

Why would you want to do eliminate the SynScan controller? EQMOD, which was developed by the UK’s Chris Shillito and other talented programmers, adds features the HC is missing. As the years have gone by, features have been added to the SynScan firmware, but it still falls behind the NexStar HC, iOptron’s Gotonova controller, and Meade’s Autostar. But above and beyond adding extra stuff, EQMOD does one very important thing: it fixes the SynScan mounts’ somewhat lackluster goto performance.

A game pad is a perfect solution for EQMOD scope control...

While the SynScan HC is usually more than adequate for imagers going after one or two targets a night with a fairly wide-field set up, for people cruising to many celestial destinations over the course of an evening—video observers or visual users covering a lot of ground for whatever reason—the SynScan HC’s goto precision or lack thereof can sometimes be frustrating.

Its shortcomings in this area are mostly the result of its simple goto alignment system. The 1-2-3-star alignment of the HC is comparable to what Celestron GEMs were using almost a decade ago. In contrast, EQMOD features sophisticated alignment algorithms and a system that allows as many alignment points as desired to be added to the alignment model—one, two, or three, is OK, but you can do ten if you want—or fifty.

In order to get the mount working with EQMOD again—I hadn’t used the driver in quite a while, largely because I hadn't used the mount much in a long time—I first of all needed to round up my EQDIR cable. While you can run EQMOD using a serial cable connected to the HC (after enabling the SynScan controller’s “PC Direct” mode, which bypasses the HC), EQMOD is more stable and reliable using an EQDIR cable.

My EQDIR cable, the Shoestring Astronomy USB2EQ6, plugs into the mount’s hand control port on one end, and one of the laptop’s USB ports on the other. That’s possible because it has a built in USB-Serial converter (recommended), but you can get models that plug into an outboard USB – serial converter cable instead. One thing NOT to do? Never connect a standard serial cable to the mount’s HC port. The voltage level will be wrong. That’s the major purpose of the EQDIR cable, converting serial voltage levels to the TTL levels used by the mount’s hand control port. EQDIR cables come in two flavors: one with a DB9 connector for the HC ports of EQ-6 (Atlas) mounts, and one with an RJ connector as on the HEQ-5 and EQ-8 (Sirius/HDX) GEMs.

I wanted to load the latest version of EQMOD, which I obtained from the EQMOD Yahoogroup, which tends to have later versions as compared to the EQMOD Sourceforge page. I also needed to fix EQMOD, which (thanks to me no doubt) had been a little squirrelly the last time I'd used it, I recalled. I suspected the problem lay in EQMOD's .ini file, which is carried over unchanged when you install a new version of the driver.

So, I loaded the new version of EQMOD and then, using the EQMOD Toolbox app that accompanies the driver, I deleted the EQMOD.ini file (if the .ini is deleted, the next time EQMOD is used a new one will be automatically created). Testing with the (included) EQMOD simulator, which is a godsend, showed my weird problems had been banished.

EQMOD is not a standalone program, it is a driver, and must be used in conjunction with a planetarium program. Most people using EQMOD pair it with either Cartes du Ciel or Stellarium, both are good choices, but EQMOD can be used with any ASCOM compatible program.

When the sky finally began to get dark, I plugged the EQDIR cable into Atlas and laptop, turned on the EQ-6, and started StellariumScope and Stellarium. I selected “EQASCOM” in the ASCOM Chooser window, and then pushed the “Properties” button to configure the driver (there’s a separate EQMOD Setup app included with the driver if you want to use that instead). I configured the usual things: com port, baud rate, etc., etc. See the EQMOD Wiki for details.

Assigning gamepad functions...

Ready to go, I checked the “Connect” box in StellariumScope, which brought up the EQMOD control panel. Since I’d already done some configuring inside using the Simulator, all I had to do was unpark the mount which, looking at the Stellarium sky display, was sitting on the North Celestial Pole just as it should have been with the mount in home position (where I’d parked it the previous evening).

Now comes the cool part. I began aligning Atlas, building an alignment model. How do you do that? It couldn’t be simpler: goto a star (since I was using Stellarium, I did that with the usual CTRL + 1 key combo), center it in the eyepiece, and press Sync in the planetarium program. I did that, choosing six bright stars scattered around the sky. Given the haze and passing clouds, I was pretty lucky to see six bright stars, so that was as many as I did.

What do you do then? That’s it. You goto objects. When you are done for the evening, you park the mount to home and shut everything down. Oh, if you want, you can add a new alignment point at any time over the course of the observing run by going to an object and syncing on it. No special procedure is required.

“OK, Unk, but how do you center a star or other object in the eyepiece? You told us the computer takes the place of the HC. Do you have to have the laptop next to the telescope?” You could do that, centering the alignment target with EQMOD’s onscreen direction buttons, but it is far easier (and more fun) to use a wireless gamepad, just like we used to do with NexRemote.

Almost any PC gamepad will work with EQMOD, and setting up and calibrating one is a simple procedure. In addition to the use of a joystick for scope movement (way better than any telescope hand control’s buttons), you can map gamepad buttons to other EQMOD functions. I, for example, have a button on the gamepad that does the sync, one that unparks the scope, one that parks it, and four that allow me to choose mount slew rates.

So, to sum up, what I did was, start EQMOD, unpark the mount, slew to a bright star, center it with the joystick, double-click the sync button on the gamepad (a double-click is required to prevent you from accidentally syncing when you don’t want to). I did the same for five more bright stars. And that was it.

How was goto performance? Stellar. Anything I asked for from horizon to horizon was in or near the center of a 12mm Plössl. That’s impressive considering the fact that my choice of alignment stars was quite limited. I was pretty good in the east, but, thanks to clouds, in the west all I had was Arcturus and Dubhe.

After alignment, I went to as many targets as I could, given the clouds—maybe twenty or so deep sky objects and stars. I let the rig track unattended for half an hour. I parked the scope, shut down EQMOD, and started everything from the beginning. Never any glitches or problems. Rock solid.

The weather soon degraded to the point where even Vega and Arcturus were invisible, so I somewhat reluctantly shut down. How was I feeling about the Atlas? A little blue. It was like the day I drove my 1996 Toyota Camry (with 250,000 miles on it) to the dealer to trade it in on a new one. When I pulled into Springhill Toyota, the car seemed to whisper, “Daddy, I don’t like this place. Why don’t we go for a nice, long drive instead?” It sure was hard to let go, since the Camry still ran just as well as she had the day I’d driven her off the lot.

Same with the Atlas, “You don’t want to get rid of me. Why don’t we look at some pretty things in the sky instead? We can even take pictures!” I’ll admit it will be hard to let Atlas go after the mount once again showed me what he can do well and simply. But there’s that back problem. At least I know someone will be getting a great mount and my good, old Atlas will get used as much as it deserves.

And, so, my C11 OTA has been sold. I'm so happy it, like the Atlas, could go to a friend.

One more then, my friends, one more, a CGEM mount. I have absolutely loved using this Celestron German equatorial, but with my back twinging today, I know I have to let it go the way of the Atlas. If you've been following this saga on Facebook and here on blog, you know that after an accident, a fall, I had three years ago, I began having intermittent back problems. They come and they go, and one thing I have learned is not to aggravate them. Especially by lifting 40-pound GEM heads onto tripods.

Case in point? Last week, I was testing my Atlas EQ-G, which would be the first piece of "too heavy" gear to go up for sale. I was careful while putting it on its tripod and all seemed well. I had a lot of fun taking pictures with the mount, and had almost convinced myself to hang onto it. Until, when I was disassembling the Atlas after three days in the backyard, I--yep--aggravated my poor back again despite my caution. I knew then that both the Atlas and the CGEM just had to go.

As for the current item, my CGEM, I've had a lot of fun with it in the couple of years I had it and will miss it. The mount never failed me, never prevented me from doing what I wanted to do in video, visual observing and long exposure deep sky imaging. You can read about some of our exploits here and here. Certainly I'll be sorry to see the mount go, but I plan to, as I mentioned a while back, replace it with a lighter GEM with a similar payload capacity.

Anyway, the CGEM is just over two years old and includes the standard NexStar hand controller, a DC power cord, AND the optional (and not exactly inexpensive) 5-amp Celestron AC power supply. The counterweight is the single 17-pound job normally included with the mount, but any CG5/Synta type counterweight will work on this mount.

Like most NexStars, the CGEM has outstanding goto accuracy. It also guides very well. Until my back began to discourage me from using it, this was my primary astrophotography and visual mount. It carried a C11 or a 6-inch f/8 refractor without a problem. Notable is that the mount was tall enough that my f/8 refractor never threatened to bump into a tripod leg no matter where I was pointed in the sky.

This is priced to MOVE at $800.00, little more than half its price two years ago. Like the Atlas, this is a PICKUP ONLY item, but, as with them, I am willing to drive a reasonable distance to meet somebody--New Orleans, Montgomery, Pensacola, Panama City, etc.

Please note that the TPI spreader shown in some of the pictures is NOT included. I have moved that to my AVX.

Oh, one last thing to add to the pile of loot. I've realized that after I sell the CGEM, I'll have no further use for my ADM Vixen to Losmandy adapter, so that goes with the mount too.

If you're interested, the best way to contact me is via Facebook Messenger. I do still monitor my old email addy at rmollise@bellsouth.net, however... If you think the CGEM might be just the thing for your observing program, I urge you to contact me without delay. It won't, I presume, last at this price.

Thanks to my recurring back problems I recently put my Celestron C11 Schmidt Cassegrain and my Atlas EQ-6 and CGEM mounts up for sale. If you are a Facebook friend of mine, you know all three went to new owners amazingly quickly. When the dust settled, I was left with a single SCT, my Edge 800, and a single mount, my Celestron AVX, which I like a lot, but…

I recently did some tinkering with the AVX—well computertinkering, mechanically it is all you can expect from its price class—and that brought some improvement to its tracking ability for deep sky imaging. Tightening up my polar alignment with Sharpcap, and really bearing down on those PHD2 brain icon settings took me from an RMS error of 2” or a bit more on a steady night to 1” or a bit more (or sometimes less) on an evening with superior seeing. The mount is now really all I need for shorter subs, 300-seconds or less, in the backyard. If I have a relatively light payload onboard the VX.

The thing is, however, that I sometimes want to go a little heavier and longer than my 11-pound 900mm SkyWatcher 120 Pro ED refractor. Sometimes I want my Edge 800 SCT for imaging, and sometimes I want my 6-inch f/8 achromatic refractor for visual use. The SCT is not just heavier than the 120, it’s got more focal length to the tune of 1400mm even with the Edge focal reducer in place. The achromatic refractor? While it’s at the limit for me at 25-pounds or so, it’s not too much for the AVX, but I am happier with it on a heavier mount—I’ve used it almost exclusively on the CGEM.

What to do, then? Well, it looked like stingy old me would just have to buy a new mount. One that would not break my back nor my bank account. I did quite a bit of looking and reading and pondering and narrowed my rather small field of candidates to two, the iOptron CEM60 and the Losmandy GM811G.

I’d had the opportunity to see my friend Bruce’s CEM60 in action last summer at the Maine Astronomy Retreat and had been impressed. This innovative “center balanced” GEM looked good, worked great, and at around 2800 dollars (once you buy the nice tri-pier tripod and a couple of other “options”) would not decimate my wallet. Most importantly, iOptron has kept the weight down to a manageable 27-pounds for the mount head but has kept the payload capacity up at an impressive 60-pounds.

The other mount candidate was a new one, the Losmandy GM811G. What’s different about this GEM? It is a hybrid. Take the R.A. assembly of a G11 and mate it with the declination assembly from a GM8. One thing that impressed me about this one other than its good looks—its components are beautifully machined rather than cast—was that it is almost a G11.

The Losmandy G11 is a mount I’ve thought about a lot over the years. In most ways, it seems perfect for me. Or would be if it weren’t just too heavy in these latter days. The G11 head is 35-pounds, approaching Atlas territory, and the tripod is the same 35-pounds, twice what the Atlas and CGEM tripods weigh.

But then came the “almost G11.” The GM811 has a payload capacity (which is stated to be for imaging) of 50-pounds. But it packs that into a 27-pound package just like the CEM60. The relatively light equatorial head would, I thought, allow me to use the mount on Losmandy’s lightweight tripod, the LW, which is a couple of pounds lighter than the Atlas/CGEM 2-inch stainless steel tripod. The GM811 is in the same price range as the CEM60, which made deciding all the more difficult.

Which should I choose? iOptron or Losmandy? I thunk and I thunk and I thunk…

Pluses for the CEM60? It’s, most of all, been on the street long enough now for the bugs to be out. Yes, I know, it’s a mass produced Chinese mount and there can be variation across samples, but from what I can tell, the chance of getting a good one is high. And if you don’t, iOptron is famous for its good customer support. Despite the odd center-balanced trope, the mount is familiar ground for me. The hand control is much like what I am used to with the Celestron and Meade HCs both in layout and operation.

There are minuses, too. Not many, but some. Chief among them for me is that with the CEM60 I would be covering the same old ground, for example hooking the mount to my PC using a darned USB-serial converter. Also, while I think the CEM60 is beautiful, there’s no denying the U.S. made Losmandy looks better with anodized, machined components. Looks aren’t everything, of course. All cats are gray in the dark. But maybe I just wanted something differentthis time. Something other than the import mounts that have been my bread and butter for over a decade.

What I liked about the GM811G is pretty much laid out above. Great build quality and great looks. And the mount delivers that at a price pretty much identical to what you’d pay for the CEM60. Another plus is the innovative Gemini 2 goto system. Not only do you have a color touch-screen HC, you can link the mount to a computer via serial, USB, or, best of all, Ethernet.

No piece of gear is without its failings, of course, and the GM811 had a few. Mainly having to do with the Gemini 2 system, which I thought might be a minus as well as a plus. It apparently had more than a few developmental problems early on. However, my research quickly convinced me it is now a settled and stable computer. It is somewhat different from what I’m used to with the NexStars and Autostars, though. Couple that with the fact that there’s no manual for it, just a collection of web pages. The one thing that made me hesitant about the Losmandy mount was the Gemini 2.

Luckily, I’d had a chance to see a Gemini equipped G11 in operation fairly recently, and that took away some of my fear. Playing with the hand control simulator on the Gemini 2 web page also helped. A lot. So did spending a couple of days reading and rereading and doing my best to understand the instructions on the Gemini 2 site.

My understanding of how Gemini 2 works began to improve when I grokked the fact that what most often confused me was the author’s, Tom Hilton’s, tendency to tell me more than I really wanted to know. Lots of information is a good thing, usually, but sometimes I just want “how,” I don’t also want “why.” When I came to this realization, I had an easier time understanding what the pages were trying to say, skipping extraneous explanations.

If you’re a Facebook friend, I’ve already spilled the beans as to my final decision there, so I won’t keep the rest of you in suspense. The winner was the Losmandy GM811G—by a nose. I am more than certain I could also have been happy with the CEM60, too.

And so, the wait began, the dreaded wait for new astro-gear to arrive in the brown truck. Looking at UPS Quantum View, I noted that the shipment would consist of three packages, and that I could expect them between 4 and 7 p.m. Monday.

Naturally Monday was a day of me being on pins and needles, and seemed to stretch on forever. At least my prediction that the UPS dude wouldn’t show up till 7 was wrong. The truck was in front of the house well before 5. My old friend Pat’s prognostication also turned out to be wrong, thankfully—he’d predicted that I’d probably only get two out of the three boxes on Monday.

Three sizable but not enormous packages were soon in the front hall. Just as with the CGEM, I thought the tall one, which was kinda banged up, must contain the tripod. The heaviest must be the mount head, and the next heaviest surely was the counterweight. Time to dig in.

The box containing the CGEM head had been so heavy I’d had to slide it along on the floor (on a towel) for part of the way to get it to the Sunroom, my usual staging area. Not this time. The equivalent GM811 box was a little heavy, but not too heavy. The box that I presumed contained the tripod was positively light.

In the Sunroom, following my usual procedure, I began with the tripod (I did indeed choose the LW option). It was well packed and hadn’t suffered any damage at all, no thanks to the tender mercies of UPS. All I had to do was spread the tripod legs, tighten three knob-headed bolts, and I was done.

Then there was the mount itself. That had to be what was in the heaviest box. Indeed, it was. Well, that and a positively enormous counterweight bar, a stainless-steel job 1.25-inches in diameter, considerably larger (and heavier) than the skinny counterweight shafts on my old Synta mounts. Now for the payoff, the GM811G itself.

I pulled the mount, which was in a plastic bag, out of the box (which was full of those cornstarch packing peanuts that my young feline, Wilbur, immediately began eating) and put the EQ head on the seat of a chair so I could free it from its plastic bag. When it was out, I was bowled over by the GEM’s appearance. For someone used to the cast aluminum of Chinese mounts, the GM811 was quite a revelation, a machined beauty with no plastic. Man, those engraved R.A. and declination setting circles are beautiful. I don’t know what I’ll do with them, but they sure are pretty.

Also in the box was a couple of pages of brief assembly instructions. Brief, but sufficient. With this mount, it’s pretty obvious where everything goes and how. I am sometimes mechanically challenged, but I had no problem putting everything together and really didn’t even need instructions.

The mount head slides into the tripod head and fastens in place with three stainless allen bolts. When I lifted the mount, and slid it into the tripod, I was again impressed. It fitted into the tripod head easily and precisely; there was no fiddling around required. Same for all the bolts and bolt holes on the mount. They threaded in easily without any fuss at all.

Mount secure, I threaded on that big counterweight bar and opened the final box. Inside was an 11-pound Losmandy counterweight and assorted hardware including a toe-saver for the counterweight bar and a set of allen wrenches—all the bolts on the mount are hex-headed allen bolts. Finally, there was the Gemini 2 computer, the hand control, the HC's coiled cable, a cigarette lighter plug style DC power cable, and the optional 15-volt AC supply I’d ordered. I might run the 811 on batteries on occasion, but I will probably use it on AC most of the time.

Time to get it going—in the house anyway. It was raining as I assembled the 811, and there was absolutely no chance of me using it in the backyard on this night. Or the next. Or the next. In a way, that was probably a good thing. It gave me a chance to figure out the Gemini 2 system in the air-conditioned comfort of the sunroom.

When I’d ordered the mount, I’d been torn about whether or not to order a second counterweight with it. Would one 11-pounder be enough for my 120mm APO or my Edge 800? I needn’t have worried. With the 120 onboard, I had to move the counterweight almost to the top of its travel to balance thanks to that enormous counterweight bar.

Next, I plugged the R.A. and declination cables, which are terminated with DIN connectors, into their respective receptacles on the Gemini computer and motors. The motors on the GM811 are, by the way, the new “tucked” style. They are kinda flipped around from the way they used to be, meaning there is little or no chance of collisions.

Other than that, all I had to do to get ready was mount the Gemini 2 computer to the tripod with a couple of bolts, plug the hand control cable into the hand control and into the proper RJ plug on the Gemini, and attach the AC power supply.

So, here we were at rubber meets road time. I turned on the power switch and the HC greeted me with a color splash page and then offered to let me calibrate the touch screen. The Gemini 2 instruction sheet informed me that it had been calibrated at the factory, however, and that calibration probably wouldn’t need to be done again, so I skipped that and was soon looking at the startup page.

There, you have several options including Quick Start, Cold Start, and Warm Start. I chose Quick Start, which takes you through the process of entering the things all HCs must know—latitude, longitude, time zone, etc., etc. That was easy enough to do, and I was able to select and enter everything by just touching the screen. Miss Dorothy, seeing what I was doing, found me a stylus designed for use with smart phones, however, and that made using the touch screen more precise. Especially when selecting smaller items like objects in a catalog list.

Once I was done entering the needed info, I thought I’d do a couple of gotos, fake gotos, to ensure everything was more or less well. With the 120mm refractor in the home position, pointed “north” with the counterweight bar down, I told the 811 to go to Arcturus. Off the mount went, and wound up pointing in roughly the proper direction given Arcturus’ current position.

How did she sound? Pretty loud. Not as loud as my CGEM, but loud enough. At first I thought I might need to adjust the worm gears as some new owners have reported they needed to do (on a certain Internet astro-forum), but I didn’t get any stalls or other errors, and decided that wasn’t necessary. Let’s face it, servo motors, which the Losmandy mounts use, are just naturally louder than steppers. The sound level wasn’t helped by the mount’s position inside near a brick wall, either.

And the rain continued to fall. I did get some more things accomplished indoors, however, installing the Gemini 2 ASCOM driver so I could use the mount with my beloved Stellarium, and getting the Ethernet interface sorted. While the Gemini 2 can communicate with a computer over either serial, USB, or Ethernet connections, the Gemini 2 folks strongly suggest using Ethernet. I am no stranger to working with LANs and Ethernet, so I thought I might as well go that route.

Wednesday, my movie day, I stopped at BestBuy on the way home and picked up an Ethernet cable. Modern PCs don’t care whether you use a “patch” or “crossover” cable, so I just bought what BestBuy had in the length I wanted, a 14-foot CAT 6 patch cable.

Standing in a long line at BestBuy turned out to be the hardest part of getting the mount working with Ethernet. Back home, I entered an IP address and a few other things in the laptop’s network setup, typed in http://gemini/, and was soon looking at the mount’s web page. You can do quite a few things using the web interface, including going to objects via a nice onscreen HC, and accomplishing many setup/housekeeping tasks for the mount. I wanted Stellarium in the mix, though.

That turned out to be even easier to set up than Ethernet. I downloaded and installed the Gemini 2 ASCOM driver (which requires the latest version of the ASCOM platform), selected it in StellariumScope, configured a few things in its set up window, and was soon sending the mount on fake gotos from Stellarium’s beautiful sky map. The Gemini 2 driver works perfectly with Stellarium and StellariumScope, and can talk to the mount using Ethernet or serial interfaces. There’s also a driver that allows you to use it with a USB connection if desired.

Then Wednesday evening came and with it clearing. I really wanted to hit the backyard, but I didn’t. It had rained at sundown, and the backyard was a damp, buggy, and humid mess. I also had a road-trip scheduled for the morrow. Dorothy and I would be going to Huntsville for the famous Huntsville Hamfest and to visit the Space and Rocket Center, so I didn’t want to stay up all night long playing “How the heck do I get this darned mount to work?”

On our return Saturday night, the sky was kinda-sorta OK, but very hazy. Unfortunately, it was already getting dark and I was positively bushed after the drive. Sunday was predicted to be better weather-wise anyway, so I put off the mount’s acid test for yet another day.

Sunday found me both excited and a little scared. The mount looked beautiful and seemedto work well, but that was inside. How would it do under the stars? The GM811 was new, and you know how it usually goes with new gear out in the backyard for the first time. I expected frustration—if not disaster—aided and abetted by sweltering nighttime temps, high humidity, and flocks of mosquitoes.

I was wrong. This was the smoothest first light run I can remember having with any mount. Even to include my CGEM, which, given its NexStar HC, was a known quantity for me. Admittedly, I did keep it simple. I didn't try to take pictures or auto-guide or anything; that will be for next time; I just wanted to polar align the mount, get it goto aligned, and play around in the hazy and humid sky a bit.

As soon as there was a little shade on my accustomed observing location in the yard late Sunday afternoon, I got the mount assembled with the SkyWatcher refractor onboard. I sure was happy I’d chosen that LW tripod. It was less of a strain on my back than even the standard Synta/Celestron tripods are. The mount head? It was somewhat of a handful, but considerably easier to lift than the CGEM or Atlas.

There wasn’t much to assembly in the field. The bolts that hold the mount to the tripod can stay threaded into the mount, just loosened. Unless you are traveling, you can leave the Gemini 2 computer attached to the tripod. Other than attaching mount to tripod, counterweight to mount, and telescope to mount (the GM811 will accept either a Vixen or Losmandy “D” dovetail), all I had to do with plug in the R.A. and dec cables, the power supply, and the hand control. I’d decided to leave the PC for some other night.

Any mount needs to be decently balanced, so that was the next step after assembly. Balancing the GM811G was a positive joy. With the friction clutches disengaged, the mount is free-wheeling in both declination and R.A. There was most assuredly no need to guess at balance as I used to have to do with my old CG5’s dec axis.

After Polaris winked on, it was time for polar alignment. I moved the scope slightly off north in declination to open up the hole in the counterweight bar so I could center Polaris in the hollow polar bore (I chose not to order the polar alignment scope). I then returned the tube to declination 90 and used Sharpcap’s polar alignment tool to dial in the pole.

Polar aligning the mount using Sharpcap, my wide-field guide scope, and my QHY5L-II guide camera was a snap. The GM811’s azimuth adjusters, especially, are just so much better than those on many of the Chinese mounts. The mount’s altitude adjustment requires you loosen four allen bolts, but that was not a big pain, and the mount stayed where it was in altitude when I tightened them back up again. In the interest of keeping my polar alignment good for a few days, I placed my Celestron vibration suppression pads under each leg. Three paving blocks would work just as well, however—or probably better.

Following polar alignment, I put the mount back in home position using a carpenter's level to ensure the counterweight bar was straight down and the tube pointed straight north. Then it was time.

I turned on the Gemini 2 computer and asked to build a model. What I did, as Losmandy suggests in their (excellent) YouTube videos, was align on three stars in the west (where I'd be doing most of my looking) and one in the east.

I chose Arcturus as my first star, and when the slew stopped, it was in the field of my 12mm reticle eyepiece. Centered it and added Dubhe and Mizar. The touch-screen direction buttons took a little getting used to, but after the first three stars I was already used to them. I never felt moved to use the “tactile” buttons on the reverse face of the HC. After lining up on the stars in the west, I selected "east" in the model screen and added Deneb to the model (I didn't do an east model, just added a star in the east to the west model to it to make pointing better if I crossed the Meridian).

I got rid of the reticle eyepiece and inserted a 13mm wide-field. Then, I went to the “goto catalog objects” screen, selected “Messier,” and told the 811 to go to M3. The mount slewed, the hand control declared "Goto done," and with some trepidation I went to the eyepiece. There was the big glob sitting dead center in the eyepiece, shining bravely through the haze and light pollution. I followed M3 with M13, M15, M27, and as many others as I could think of. The Gemini 2 never missed, not even on objects east of the Meridian.

At this point I was literally drenched in sweat and the bugs were biting. There was just nothing for it; it was that dreaded time, time to pull the big switch. I could have parked the scope and reused my alignment the next run, but the somewhat dire weather forecast suggested I'd be dissembling the mount and scope and returning them to the Sunroom on the morrow, so I didn't park, just killed the power.

So, were there any problems or hiccups? Only one. I need to change the 811’s safety limits a bit. The safety limits determine where the mount is in regard to the Meridian when it does a Meridian flip, when it changes sides from east to west or vice-versa. Get too close to the Meridian before doing that during a goto and a longer-tubed telescope can bump into the tripod. As my f/7 refractor threatened to do when I sent it to M57, which was near the Zenith. I had to push the "stop" button on the HC to prevent a collision. I just need to tell Gemini that it needs to do the flip a little sooner than what is dictated by the default settings.

Otherwise, I need to devise an accessory tray of some kind for the LW tripod, which doesn’t have one. On this first night, I settled for setting up a folding aluminum camp table next to the tripod to hold the HC, the mount power supply, and the power brick for the DewBuster heaters.

Next time? I intend to see how the new baby tracks and guides. Which is the ultimate test for any telescope mount. We shall see, but based on my first light experience, I believe this is the beginning of a beautiful friendship.

I’m not talking about new-fangled video observing, “electronically assisted astronomy” as the denizens of a certain contentious forum on a famous (in a small amateur astronomy sort of way) website call it. I’m not talking about using digital CCD/CMOS cameras with short exposures to simulate video observing. I am talking about real-deal video observing with analog video cams.

That doesn’t mean I don’t like the new style digital astro-video cameras. I’ve reviewed a couple of them for Sky & Telescope Test Reports and was impressed. Their strength is that they are far more able to deliver pretty, smooth-looking images than the analog cams were. And those images sure are easier to get into a computer for manipulation than analog video was. You no longer need one of those blasted frame-grabbers; just plug a USB cable into the camera and laptop and you are ready to go. It ain’t all gravy, though. Analog cameras like the Mallincam Xtreme are still more sensitive than almost anything else.

Those were some of my thoughts as I pulled my Xtreme from her dusty case and mounted her on a telescope for the first time in nearly three years. I was in a hurry to get some images for a magazine article, and was pretty sure video would be the quickest way to do that. Which is just one of old-fashioned style video’s pluses. But why, then, had my Xtreme sat unused for so long? Maybe because I'd rarely observed with anything but video when I was doing the The Herschel Project.

The Herschel Project, which I began in earnest in 2009, was my quest to view all 2500 of the deep sky objects recorded by William and Caroline Herschel. It was the biggest observing campaign of my life, and finishing it in about three years as I planned meant night after night of pedal-to-the-metal observing, much of it with video, was required.

While I could have done all, or nearly all, of the H objects visually with my larger scopes, that would only be true given excellent dark skies. At my club site, I needed video to reliably bring home all the small and dim galaxies that infest the list. That’s why I started using video for the Project, anyhow. Frankly, I became so fond of observing the Herschels with my Mallincam Xtreme that I began using it even under dark skies, like in Chiefland.

For a typical Chiefland Astronomy Village run, I’d set up my NexStar 11GPS, Mallincam (Stellacam in the beginning), and sit under a tent canopy until three or four in the morning, controlling camera and telescope with a laptop PC running SkyTools 3, NexRemote, and the Mallican control software. I considered it a poor evening if I didn’t log and record at least 100 objects. In a typical three-night CAV visit I could easily bag 300 of the list’s faint fuzzies.

So, I basically wound up doing nothing but video during the over three years of the Herschel Project. It was fun, but after that much of it I was glad when it was “fun is fun, but done is done.” After crossing the finish line, I wanted something different, which turned out to be DSLR imaging most of the time and visual the rest of the time. There’s also no doubt the changes I’ve been through personally over the last three years have meant that, while I’m still an enthusiastic amateur astronomer, I’m quite not as hardcore as I was during the go-go days of the Project and not as apt to set up the ton of gear a video run requires.

Anyhow, as I mounted the old Xtreme on the rear cell of the C8, some great memories of the height of the Project came flooding back. All those evenings at Chiefland counting Herschel galaxies by the score in places where I’d never seen a single galaxy, like the wilds of Boötes.

The more I thought about it, though, the more astronomy video seemed to be mostly a creature of the Herschel Project for me—even though I’d become infatuated with the idea six years before the Project began, in 2003, at that year’s Astronomical Convention held in Nashville. There was a Stellacam and Meade 10-inch LX200 SCT set up in the parking lot one night and I couldn’t believe what they pulled in from orange-pink skies near the Nashville airport. I just had to have a Stellacam.

I got one, too, shortly thereafter, and while I used it a fair amount at first, that was just at first. It was soon back in its case for extended periods. I couldn’t find a use for it. The video camera seemed neither fish nor fowl. Lacking the personal and immediate magic of visual observing, but not offering the more finished pictures of “real” astro-cams.

That was the way it was until I started in on the Herschel Project. When I did, everything finally clicked video-wise. As above, I could observe dozens and dozens of objects every clear night, literally tearing through the 2500 DSO list. No, they didn’t look as good as they would have in, say, a long exposure DSLR image, but, frankly, many of those objects, as mentioned above, are bland, small galaxies, and don’t have a lot of pretty to them anyway. As opposed to visual? Man could I go deepwith video.

I’d known that even before the H-Project began, like the night at the Deep South Regional Star Gazewhen I began imaging Hickson galaxy groups and found my C11 and Stellacam (which was limited to 10-second exposures) could show any Hickson group member visible in the Digitized Sky Survey Plates, which were taken with the 48-inch Schmidt Camera at Mt. Palomar. Yeah, I was going deep, real deep, but without a 30-inch telescope to haul around (and pay for).

When my desire for color led me to replace the Stellacam with a Mallincam Xtreme about of a third of the way through the Herschel Project, I found just how deep I could go. A 1-minute exposure would take me to the realm of quasars, easily recording the ancient objects (see the quasar video at the bottom of the page, which I did in 2015 just before I put the Xtreme away) as well as the little sprites of PGC and UGC galaxies that haunted nearly every field.

Don’t get me wrong; I wasn’t just seeing the ferociously dim, either. There was also detail, plenty of detail, and not just in brighter objects. As the Project was winding down, I hunted Arp (peculiar) galaxies for a while. Not only could I see them, I could almost always at least make out a trace of the odd details that led Halton ARP to add them to his list.

But then the H-Project was over. In addition to me wanting prettier pictures when I took pictures, there was also that “less hardcore” take on our avocation. There is no denying analog video is “stuff” intensive. You have multiple cables, a PC, power supplies, and, if you don’t want to involve frame grabbers, you’ll need a separate monitor to view the video and a DVR of some kind to record your objects. The times I wanted to pull out that amount of gear became fewer and fewer as the H Project receded farther and farther into the rearview mirror.

And there things remained. Oh, I did do a bit of playing with the excellent little Revolution video imager, which I still think is a wonderful buy, and is about as self-contained at kit as you can get, but it had literally been years since the Xtreme gathered photons. Not since that quasar run during my final spring Chiefland expedition in early 2015.

Which brings us to today. What did I think of the Mallincam Xtreme mounted on the back of the Edge 800 now? Some of the old annoyances remained. I don’t like frame grabbers, so I had to drag out a monitor (my old portable DVD player) and a video switch to route signals to it or to the DVR as desired—the camera doesn’t have enough drive to allow it to be hooked to both at the same time without an amplifier. And wouldn’t you know it? The first video cable I hooked between camera and switch turned out to be bad. So it goes in the analog world.

Those were the annoyances, however. The strengths of video were also on display. I was correct about how easy it was to get recognizable pictures quickly. Once I had everything properly hooked up and the bad video cable banished to the trash, it was a snap to produce usable images.

At first, I was afraid I wouldn’t remember how to run the Mallincam control software on the laptop, but it all came back rather quickly. It’s pretty user friendly as esoteric programs go, and I used it a heck of a lot over the years of the Herschel Project. After just a little fiddling around with the settings I was getting surprisingly nice video pictures.

The images I needed for the article safely on the DVR’s SD card, I had time for a little fun before the clouds rolled in, and pointed at some of the late summer DSOs sinking in the west (I absolutely love the new Losmandy’s Gemini 2 goto system). No, the video pictures didn’t have the look of carefully processed DSLR photos, but you know what? They were not bad at all. The stars weren’t grain-of-sand pinpoints, no, but there was nice color, and the frames coming over were not nearly as grainy and noisy as I “remembered.”

So, the final verdict on analog astro-video. REAL astro-video, if you will? I think it still has a place for those of us who own analog cameras, or who are interested in an inexpensive set up like the Revolution Video Imager (a mere 299.00 including a monitor and the other accessories you will need to get going). For those who don’thave an analog camera and want a top-of-the-line one like the Xtreme? Not so much.

The problem is that the base Xtreme is $1300.00, more than some of the new digital video setups (including the Mallincam SkyRaider DS2.3+ and the Infinity from Atik). The premier Mallincam now, the Xterminator, is over $1700.00. While these analog cameras are definitely more sensitive than their digital sisters, that sensitivity does come at the expense of more noise, smaller sensor chips, and images that are more difficult to process. The digicams are actually quite sensitive and more than usable for near real-time video style observing, but they also can be used to produce respectable long integration images.

I do have an Xtreme, however, it still works every bit as good as it did the day I put it away years ago, and I doubt it will stay in its case for another three years. I’m not going to take on the Herschels again, but when I want to capture something way far, far away on the edge of the Great Out There, the Xtreme, the Revolution, and their analog sisters are still the winners hands down.

Note: You can view these videos full-screen by clicking "Youtube."

Note 2: Have you heard there is now a place on Facebook where you can buy and sell astro-gear? There is: https://www.facebook.com/groups/1873482632865645/ It's administered by the good folk at TPI Astro...check it out.

How do I like my new Losmandy GM811? That’s a question I’ve gotten a lot over the last few weeks. But what is the answer? Given the limited amount of time I’ve had to use the telescope mount, I can at least say I like what little I’ve seen so far.

The problem, as you’ve no doubt guessed, has been the weather. Mostly clouds, and if not clouds, heavy haze. There has yet to be an imaging-worthy night since the mount arrived from California, but I have had an opportunity to use it visually a couple of times, so that’s what this will be about.

I do hope to use the Losmandy for picture taking at its first star party, the Deep South Star Gaze later this month. I hope so, anyway. Alas, the DSSG comes early this year, in late October, and historically, that’s not a recipe for the best skies (not that I want to jinx things; I'm knocking on wood right now ).

Set Up

Sure, the Losmandy mounts are pretty—all that beautiful machining and anodizing—but that’s not what attracted me to the GM811. What did was its good weight to payload ratio. The Chinese mounts (with the exception of the iOptrons) have a fatal flaw for those of us who don't want to or can't wrestle with heavy GEMs. You get decent payload capacity, but that's at the expense of high mount weight. The Atlas and CGEM, for example, can handle maybe 40 pounds of telescope and gear for imaging, but they weigh in at around 40 pounds (for just the mount head).

In contrast, the GM811, which is a Losmandy G11 RA assembly mated to a Losmandy GM8 declination assembly, weighs less than the Syntas at 27 pounds, but has a payload capacity of 50-pounds. 27-pounds is about the limit of what I feel I should be lifting given my current back problems, and it’s really not bad at all. I could reduce it even further if I removed the mount’s big, honking counterweight shaft, and I will probably do that for transport to the star party. For use in the backyard, however, I can manage it with the bar in place.

There’s also the question of how easy the GEM head is to attach to the tripod. Lighter weight won’t help if you have to fiddle around getting the mount head settled on the tripod. The Losmandy tripod makes that easy. The head is a cylinder with slots for the Allen attachment screws on the mount head. Line the screws up with the slots, lower it into the tripod, turn to engage the screws, and tighten ‘em down. No threaded rods or stuff like that to mess with.

Choosing an alignment star...

Speaking of tripods, how is the one I chose for the GM811, the Losmandy LW (lightweight) tripod? I love it. It’s plenty sturdy given my modest loads, a C8 and 6-inch class or smaller refractors of moderate focal lengths. The big deal for me? It is strong and sturdy, sure, but it weighs about half what the 2-inch steel legged Chinese tripods, like the one that was furnished with my Celestron VX do. Any problems? As I’ve mentioned previously, there’s no accessory tray. I need to make one before the star party, I guess. For now, I’ve been getting by with a camp table set up next to the telescope to hold the GM811’s HC and power supply.

Mount on tripod, let’s attach the scope. The GM811 has a dual saddle that will accommodate either a Vixen (all I have now) or a Losmandy D style dovetail. Install the mount’s declination counterweight on the dec shaft (always do that first), slide the scope’s dovetail into place in the saddle, lock it down and you are ready to balance—which you do just as you would with any other German mount.

Is balancing overly critical with the Losmandy? No, but if you are way off balance, you can get motor stalls. One night out with a telescope I am testing, a 5-inch range triplet APO, I wasn’t careful about balancing; I didn’t take into account the heavier weight of the objective end as compared to my personal scope, a doublet APO of similar aperture. I’ll fess up: I didn’t balance at all. I just set the scope up as I would my lighter doublet refractor. With the scope badly off balance (it turned out), I did eventually get a stall, but that’s been the only time despite me doing dozens of gotos all over the sky in the course of my scope-testing.

How about the Losmandy’s clutches? Well, they are different from what you may be used to coming from Synta and Meade. The Syntas and their kin don’t really have clutches. They have locks. The Losmandy has real slip clutches. You only need to lock them down tightly enough so the scope is held firmly enough that bumping it or changing eyepieces doesn’t move it. With the power on or off, you can then move the telescope by hand—like to put it in home position—without loosening or otherwise fooling with the clutches. Naturally, moving the scope after goto alignment will cause you to lose said alignment, but I’ve found the clutch paradigm very useful during setup/polar alignment.

Polar Alignment

Center the star...

It’s time to polar align. How sensitive is the GM811’s Gemini 2 goto system to polar alignment errors? I’m not sure, since it’s so easy to do a good polar alignment these days. The mount computer features a built in polar alignment routine, but most people will probably opt for the new ways now: Polemaster or Sharpcap. I’ve chosen Sharpcap since I have a guide scope/guide camera perfect for use with the program’s polar alignment tool.

I set up the mount with the polar axis pointed as close to north as possible (using a compass). I don’t take incredible pains to do so, but I try to get close. When Polaris peeps out, I plug my QHY5L II guide cam, which is inserted in an Orion 50mm finder-style guide scope, into the PC, and bring up Sharpcap. In just a few minutes, the program will have me polar aligned very accurately indeed. If Sharpcap makes it easy, the GM811’s altitude and azimuth controls make it easier. They are smooth and precise and quite an advance over the crude (and I do mean crude) alt-azimuth controls on my old EQ-6.

Goto Alignment

The Losmandy goto system, the Gemini 2, seems to have a reputation for being “hard to understand” and “user unfriendly.” That worried me when I was mount shopping, but after using the mount just a few times, I’m scratching my head over this criticism. The Gemini 2 is no more difficult to align and use than the SynScan or AutoStar or NexStar controllers. Maybe easier. Certainly, the large, full color (or just red if you prefer) LCD screen is easier for me to read than the small monochrome displays of those other HCs. The alignment process itself is no more complicated than what you have with NexStar or Autostar.

You start out with the GM811 in the home position—counterweight down and tube pointed north. At first, I was obsessive about that, being used to my old EQ6—you had to be careful to home that mount accurately if you wanted a decent alignment. So, I used a carpenter’s level to home the Losmandy. I subsequently found out, however, that just moving the mount RA either by hand or with the hand controller until the counterweight bar was straight down by eye, and moving the mount in declination until the declination setting circle read 90-degrees was good enough.

When I am in home position, I turn on the Gemini 2 computer, and after the HC boots, I click (touch) “Cold Start” if I am not beginning from Park. Next, I click “Modeling” and the HC asks me if I want to create a model on the eastern or western half of the sky. If I am going to be doing most of my imaging/observing in the west, I choose that. If east, I’ll pick east.

Accepting an alignment star...

From there, things are much like they are with any other goto hand control. Well, sort of. You can choose as many stars for alignment as you wish rather than being limited to two or three. Being lazy, however, I usually leave it at three stars in the east or west and one additional star on the opposite side of the Meridian. Like any other goto system, you’re best off choosing stars that are well separated and not too low to the horizon.

After I click “west” or “east” I will be presented with a star choice for alignment star one. If I like it, I’ll click “goto.” If I don’t like it, I’ll click “west” or “east” again to get a different star. After clicking goto, the mount heads for the star. With a good polar alignment and assuming I’ve been reasonably careful with home position, the star will always be in my finder, usually in the inner 50% region, and sometimes in the eyepiece. When the scope stops I’ll use the virtual (onscreen) direction buttons or the real buttons on the HC’s reverse face to center the star. There’s an onscreen button that toggles between slewing and centering speeds. When done, I click “model.”

“Model” brings up a screen with a button that says “align.” Press that or your star will not be added to the sky model. When you do, you’ll be presented with a screen that gives various alignment error figures. You don’t have to do anything there other than hit “back,” which takes you backto the star choice screen, where you select the second star.

A full-blown Gemini 2 alignment involves two models, one for the eastern and one for the western halves of the sky. Each model can be composed of a bunch of stars. Me? I never do that. Haven’t yet, anyway. I do three stars on my favored half of the sky and one more on the other side. How do I do the one for the other side? On the alignment star choice screen, I just choose the opposite side of the Meridian. If I aligned on three stars in the west, for star four I will push east (and vice versa). That will not build a model for the eastern half of the sky; it will just add an eastern star to my western model, which will make gotos more accurate if I cross the Meridian and wind up in the east half of the sky during the evening’s observing run.

So, to sum up, I push “cold start” and then “alignment,” choose my favored side of the Meridian, and center three stars. When I am finished with the these three, I add a fourth star on the opposite side of the Meridian and I am done. If this still sounds confusing, play around with the Gemini 2 “simulator” at http://gemini-2.com (“Gemini 2 Tutorial”). Which is where the HC pictures here came from.

Press "back" to choose star 2...

I am aligned with only four stars. How good is that alignment? I’ve found it’s good enough that anything on either side of the sky will be in my moderate focal length telescopes when they are equipped with a medium power wide-field eyepiece—say a 12mm. I do find objects in the half of the sky where my three alignment stars reside are closest to the center, but even given my minimalist Gemini 2 alignment, the mount has never missed an object. Even the Moon, which can be difficult for goto systems, is always in the field, even if it’s on the other side of the Meridian from the “big three” alignment stars.

How do I get to the objects of my desire following alignment? Once again, it’s not much different from the way you do it with other HCs, and simpler than some. Clicking “goto” on the main screen (the one with the direction buttons) brings up a page that allows me to choose classes of objects: “Catalog Object” (deep sky objects), Solar System, Coordinates, etc.

Assuming I want to go to a deep sky object, I’ll press “Catalog Object.” I’ll then be presented with a listing of DSO catalogs. I choose the catalog I want, say “Messier,” and on the screen that appears next I enter the object’s number. Hitting enter gives the target’s stats. Pressing the screen's goto button will then slew the scope to the object. That is all there is to it. There are many options available with the Gemini system: you can save favorite destinations, enter coordinates to go to objects like comets, and upload new catalogs to the HC, but basic operation is, yeah, pretty darned simple.

Once you’ve got your feet wet using the mount with the hand control, you may want to give operating it with a laptop a go. I won’t bore you with the details again—I talked about this at some length not long ago—but suffice it to say the mount is no more difficult to interface to a computer than the Celestrons or Meades are. Actually, it can be easier, since you don’t have to mess with a dratted USB-serial adapter. You can connect mount to scope with an Ethernet cable (you can also use serial if you insist).

Some people find setting up Ethernet a little difficult, but if you follow simple directions at Gemini-2.com it is pretty easy. If you have trouble, I will be happy to help and can definitely get you going (send me a Facebook message or comment here). Once the Ethernet interface is active, a laptop can command the mount with the Gemini 2 ASCOM driver using Stellarium, or Cartes Du Ciel, or TheSky or any other ASCOM compatible program.

Choose an object catalog...

When the Ethernet cable is squared away, you can also operate the mount with a web browser without using any astronomy software at all. Built into the Gemini 2 computer is a little website. You don’t need Internet to connect to it, just that Ethernet cable. Enter the URL, “gemini” into your browser and up will come a page that allows you to goto objects, move the scope, edit mount parameters and do many other things. Pretty slick.

That computer stuff ispretty slick, but the takeaway for new users should be that the basic operation of the GM811 (and other Gemini 2 equipped mounts) is little different from the Meades or the Celestrons or the SkyWatchers.

“That’s cool, Unk, but how is the mount mechanically?” For me, it’s a dream. Everything is just so much nicer than the inexpensive mounts I’ve used over the last 15 years or so. In addition to the much better alt-az adjusters and the cool friction clutches, the R.A. and declination movements of the GM811 with those clutches undone are free and easy, making it a joy to balance even lighter scopes.

How solid is the Losmandy, though? The mount is advertised as having a 50-pound payload capacity, and while I haven’t approached that with my modest instruments, it is remarkably solid and shake free with them. My 6-inch f/8 refractor has a tube long enough to challenge the stability of some mounts—a longer lever arm can cause worse shaking than higher weight—and is very steady with the GM811.

To sum up? The GM811 is not a top tier mount price-wise. It is certainly not a Mercedes or a Porsche. Nevertheless, it’s solid and I believe it will be very dependable. It might not be a Mercedes S-Class, but I feel like I’ve at least moved up from Kia and Hyundai to a Toyota Camry or a Honda Accord, and that is more than good enough for me, campers.

In the Nick of Time Department

Revolution DVR...

As you may have gathered from the last installment of this blog, I’ve become somewhat interested in doing astro-video again. I got out my Mallincam and my Revolution cameras, and both were fine. What wasn’t fine was my little Orion DVR. It was obviously on its last legs. Not electronically, but mechanically. The switches and connectors were failing. That was OK. I definitely got my money out of it—I used it heavily for much of the Herschel Project after purchasing it seven years ago. But what was I gonna do now? How would I record my video images? How would I get them into a computer for processing into deathless masterpieces?

Up stepped astro-video guru and all around nice guy Mike Fowler of Orange County Telescope. He said he had a new DVR, one similar in size to the old Orion, he thought I might like to check out. I don’t believe in coincidence, but if you want to say this was one, I’ll just call it a happycoincidence. I’ve now got Mike’s Revolution DVR in hand and it is a cute li’l thing. If only the skies were cute. Instead they are hazy and nasty and haven’t allowed me to try the DVR with my beloved Revolution camera yet. Expect report when I am finally able to do so.

You can’t expect everystar party to be great. Sometimes, often through no fault of the event itself or its organizers, things just don’t quite pan out for you. So it was for me with the 2017 edition of one of amateur astronomy’s longest running events, the Deep South Star Gaze.

I suppose part of the problem was that I just wasn’t as excited about the year’s DSSG (née “Deep South Regional Star Gaze”) as I used to be. Which doesn’t have a thing to do with the DSSG. It has to do, to begin with, with where I live now.

Out here in the suburbs, I have a zenith limiting magnitude of about 5 on a good night, far, far better than I had downtown at old Chaos Manor South. I can observe and even image profitably from the backyard. Sky gonna be clear for two-three-four-five nights? I can leave my telescope set up in my secure yard just like I do at a star party.

Even given the current nasty weather pattern, I can sometimes get 7 – 10 nice nights per month out here in Hickory Ridge, nights with no or minimal Moon. So, there’s just not the level of anticipation there was when I might, if I were very lucky, get one clear night every month or two that coincided with a club dark site observing session. Back then, a week or so at a star party was just heaven. How I longed for those deep sky photons after being deprived of them for months.

Despite the weather forecasts, the field was filling up...

My current mindset also has to do with work—or the lack of it. I am now what they call “semi-retired.” While I continue to teach one day (and night) a week for the Physics Department at the University of South Alabama, and am a Contributing Editor at Sky & Telescope, it’s not like I’m snowed under. When I was still doing my engineering gig, commuting at least a couple of hours a day (and working plenty of hours during that day), a star party wasn’t just an opportunity to observe; it was a much-needed vacation.

At first, it was wonderful to be free of the rat race. I remember Saturday afternoon at the Deep South Spring Scrimmage in 2013, the year I retired at age 59, thinking maybe I’d better go ahead and pack some of the astro-junk in preparation for an early departure Sunday a.m. “Wait a minute. I can leave as late as I want Sunday. I don’t HAVE to go to work Monday!” That was great for the first couple of years, but by 2015, a trip to an astronomy event began to have slightly less appeal than it did in the years when I really neededa break.

That’s where I stood as the October new Moon and DSSG 2017 approached. I wanted to be back on the Feliciana observing field, hanging out with old friends and doing some astronomy from a nice and (amazingly) dark site, sure, but I wasn’t as crazy for it as I used to be.

“The longest journey begins with a single…” yadda-yadda-yadda. My first step was loading the 4Runner, Miss Lucille Van Pelt, with the gear we’d need for four full days at the Feliciana Retreat Center in the wilds of the Louisiana piney woods.

In recent times, we’ve tended to do three full days, but we thought doing Wednesday through Sunday morning instead of Thursday through Sunday morning might give us a better chance of getting in at least one good night if the weather turned bad, as it can down here in mid-October—DSSG would be early this year thanks to the New Moon date. As the month wore on and the star party approached, it looked like poor weather was exactly what might happen.

When the week of the event finally arrived, the prognostications on wunderground.com showed happy little Suns and Moons for Tuesday and Wednesday, but after that it was partly cloudy days and nights, and, by Saturday, lightning studded thunderstorm clouds. In fact, the weather forecast for Saturday night began to sound dire.

Our setup...

Anyhow, I’ve been to so many star parties over the last twenty years that packing for one is second nature. I know where everything should go in the truck, and, most importantly, what should go in. I make sure nothing gets left behind by relying on checklists I’ve refined and revised over the years. Nothing gets checked off till I physically place it in the 4Runner.

It was all pretty standard stuff, but with a couple of changes: a new mount, a Losmandy, and a new telescope, a 115mm APO. If you’re a faithful reader, you know I recently sold two of my beloved Synta mounts, the Atlas and the CGEM. I still have my AVX, but what would travel to the star party with me would be my new GM811G.

While I’d been able to try the Losmandy out in the backyard, the cloudy early fall weather prevented me from giving it a good shakedown cruise, and I was looking forward to finally doing that. Thanks to its design, the GM811 and its tripod actually took up less room in the truck than the CGEM had, despite the Losmandy’s substantially higher payload capacity.

New telescope? No, I didn’t go out and buy yet another refractor. The star party would be more than just a pleasure trip for me this year. That APO, a loaner, would be the subject of my next Sky & Telescope Test Report. That was another reason Dorothy and I’d decided on a Wednesday rather than Thursday departure. That would allow me more time to put the scope through its paces.

Once Miss Van P. was loaded, I sat back and relaxed with a little Tuesday night TV. There was really nothing more I needed to do to prepare for Deep South. I hadn’t been asked to give a presentation this year, so I didn’t have to spend time reviewing and agonizing over a PowerPoint.

The drive to the Feliciana Retreat Center near Norwood, Louisiana was a relaxed and uneventful one when we finally got going. There wasn’t much reason to start the three-and-a-half-hour drive too early. With DSSG taking place with DST still in effect, we’d have plenty of time to set up before sundown. We settled on 11:30 or so as our hit-the-road time. That would allow me to pick up my books from my Local Comic Shop (Wednesday is New Comic Book day, of course), and eat Chinese afterwards, as I always do on Wednesdays.

I'd planned on sitting here while taking pictures...

After a little more than three hours on Interstates 10, 12, 55, and multiple Louisiana back-roads, we were rolling onto the Feliciana Retreat Center grounds. We headed for the field straight away to stake out a spot. The weather had been good Tuesday night, and looked to be even better Wednesday, so it wasn’t much of a surprise that there were already plenty of eager amateur astronomers on the field. My usual place along the eastern side was taken, so I picked one on the northeastern field edge. The view to the south was compromised by a tree, but the light dome in that direction meant I wouldn’t be giving up much.

Up went the tent canopy, the tripod, the mount, and the telescope. It was hot work since we were back into another warm spell after having a few almost fall-like days, but not too bad. By the time an hour had elapsed, everything was ready to go for what looked to be an outstanding evening. The skies were slightly hazy, but only slightly, and were that deep cerulean that spells “good things.”

Setup done, Dorothy and I drove to the lodge to unpack in our small motel-like room. I noted with approval that the FRC had done some maintenance and remodeling, and that our room looked cleaner than the one we had the previous year.

Thence back to the field for the door prize drawing. No, we didn’t win a thing, but we’ve won (or at least Dorothy’s won) plenty over the years. Drawing done, I did the final preparations for the coming evening’s observing run, and we returned to the Lodge for dinner.

When you’re at a star party with not much to do during the day, food often assumes a more than normal importance. Especially when, as at DSSG, there’s no nearby town with decent restaurant alternatives and other diversions. One thing that had always been good, very good, at the FRC was the meals. Oh, there was one year when the portions were a little skimpy, but the food that was served was high in quality. Not this year. The food was, to put it plainly, terrible.

Start with dinner. Tiny pieces of chicken that were as dry as the Sahara. The next morning at breakfast, I finally identified the yellow disk that was plopped onto my plate as eggs. The plastic-like thing did taste faintly of eggs, anyway. One evening there was jambalaya that tasted like it came straight out of a can, and was accompanied by a side of canned corn. Another “memorable” meal? Salisbury steak that was apparently made the same way MacDonald’s makes chicken nuggets: smash some powdered something together in a mold. I expected better based on past experience, and knew the Feliciana Retreat Center could have done better if they’d wanted to. I survived largely thanks to the salad bar (which also wasn't what it used to be).

While the food was reasonably priced, they weren’t exactly giving it away, and it was certainly not a good value. I am aware the FRC has had its share of financial problems and needs to economize, but this is not the way to do it. Anyway, I would have gladly paid five dollars more a meal for good food, and I suspect other star partiers would have as well.

Getting dark, finally...

Dinner, such as it was, concluded, what was the plan for Wednesday night? Astrophotography. I don’t generally like to jump into picture taking on the first evening when I’m tired from the drive and set up, but the weatherman was beginning to suggest that if I were to get any pictures, I’d have to get them Wednesday night.

How was aligning the GM811? Polar alignment was exactly the same as what I’d been doing with my Chinese mounts for the last six months or so, polar alignment with the PC program Sharpcap using my guide scope and guide camera. The difference was that the much more precise altitude and azimuth adjusters on the Losmandy made it far easier to get a dead-on alignment.

Goto alignment was similarly easy. Using the mount’s Gemini 2 hand control, I centered three stars in the west, where I’d be doing most of my imaging, and one star in the east. While you can build multi- star models on both sides of the Meridian, my experimenting in the backyard had shown that four stars total was more than enough for the mount to yield excellent pointing accuracy.

OK. Fired up the laptop, connected to the mount over the Ethernet cable, started my camera control program, Nebulosity, and guiding program, PHD2, and was ready for picture-taking. What first? Well, how about good, old M13?

I clicked on M13 in Stellarium and the mount headed to the Great Globular, stopping with it centered in the frame of my DSLR, which was displayed on the laptop thanks to Nebulosity. I focused using my Bahtinov mask and Neb’s fine focus routine, and began a series of 300-second exposures.

Unfortunately, when the first one finished, I could tell I had big problems. For some reason, the images were in black and white. The program appeared to be debayering them, since they looked normal rather than having the pixilated appearance of non-debayered shots, but they were in black and white and nothing I tried changed that.

OK. I’d work on the computer in the morning (images were normal with the DSLR itself, but I didn’t have a cable release/intervalometer, so I couldn’t use it for long exposures without the laptop). For tonight, I’d just give the refractor a visual workout and spend some time getting more comfortable with the new mount.

How did the APO do? To find out, look for my Test Report in an upcoming issue of S&T. I will say it surprised me. After a while, I forgot I was using a telescope with "only" 115mm of aperture and just enjoyed the beauties of the deep sky it showed me.

As for the GM811, it never faltered. Gotos were dead on in the west; in the east it placed objects in a widefield eyepiece despite me only having aligned on one star on that side of the Meridian. I hung in till about midnight—my usual turn-into-a-pumpkin hour in these latter days, I must admit—before parking the mount and walking back to the Lodge to get some shuteye.

After eating what I could of breakfast the next morning, it was time to troubleshoot the laptop/Nebulosity problem. Sitting in the dining room after breakfast with the PC and camera, I made absolutely no progress. The problem persisted. All the images were monochrome. I was pretty sure uninstalling and reinstalling Nebulosity and the camera drivers would fix things, but that wasn’t possible. The Internet was so slow at FRC this year that my laptop would barely even connect to it.

Really liked my friend Dave's new mount...

So, no pictures Thursday, either. It didn’t look like the evening would be imaging worthy anyway. Stepping outside the Lodge and looking up revealed a sky blighted by high cirrus and even a few “mare’s tails.” If the camera had been working properly, I’d no doubt have tried some shots Thursday night, but it wasn’t, so it would be another visual evening.

In the afternoon, it was prize drawing time. Again, we didn’t win a thing. Well, Dorothy wouldhave won a nice TeleVue eyepiece if she’d been on the field for the drawing, but she wasn’t. The drawing’s time was different from what we thought it would be—I was only present because I happened to be on the field fiddling with my gear.

Unlike in past years, “must be present to win” meant, “not just at the star party, but on the field.” Unfortunately, we rarely knew when a drawing—or anything else—would take place. No schedule was posted anywhere that I could find, so Dorothy and I were in the dark about “when and where” much of the time.

Other than that, it was a nice afternoon spent getting reacquainted with many old friends. Maybe the best thing about this year’s event was hanging with the people I see too seldom, including Charles Genovese, Walter Serrat, Walt Cooney, Barry Simon, Dave Diaz, Ron Marcella, Greg Thompson, Bryan Shirkey, and many more (I did note a couple of familiar faces were missing, perhaps thanks to the worsening weather forecast).

Also onsite was Scott Roberts, who I’d last seen ten or twelve years before when we’d both been guests at one of Herb York’s old Optics Expo shindigs in Anacortes (Washington). As you probably know, after years at Meade, Scott was chosen to helm the new Explore Scientific. Not only did Scott do a presentation at Deep South this year, he donated many of his wonderful eyepieces and an APO refractor as prizes.

Finally, it was sky watching time Thursday night. I unparked the mount and was ready to go immediately, no alignment required. Conditions were not horrible early on, just not good. Those cirrus clouds were making their presence felt, and it was obvious the sky was slowly going south.

I had a lot of fun touring the early winter open clusters, but by midnight even NGC 457, the bright E.T. Cluster, was fading away, and I gave up. The dew had been incredibly heavy, and I was damp from head to foot and uncomfortable after spending a night at the eyepiece out in the open instead of sitting at the computer under a tent canopy as I’d intended.

Friday afternoon, the weather forecasts we were pulling up on our smartphones (when we could do that given the state of the Center’s Internet) indicated “severe” was not too strong a word for what would happen Saturday night. Dorothy and I decided we’d leave on Saturday morning. Why sit and watch it rain in the FRC Lodge when we could do the same thing at home in comfort?

I got a couple of good Losmandy tips from my friend, Tim...

To that end, I packed the tent canopy and most of the other gear Friday afternoon. Even if it didn’t rain Friday night, the dew would again be heavy, I was sure, and nothing is more miserable than packing wet gear. I left the scope up just in case, but that was it.

Friday night, I wandered out to the field a couple of times, mainly just to shoot the breeze with various and sundry fellow observers. There may have been a few sucker holes over the course of the evening, but not many. I’d covered my scope and mount at sundown, and left them that way. I whiled away the night watching movies in the lodge.

Saturday morning, we were up and on the road before breakfast. We might have stayed until ten for the prize drawing if we’d known it was going to be at ten, but we didn’t, so we didn’t. The trip home was, like the trip out, uneventful. While I was rather put out at the way things had unfolded this year, I could be philosophical, having seen more than a few star parties go down in flames for me over the years, “Well, that’s just the way the old cookie crumbles!”

In retrospect, we made a good decision. The weather Saturday night was indeed severe. Apparently, the FRC actually lost power briefly Sunday morning, something that’s never happened before despite some fierce storms here and there over the years. Absolutely no viewing Saturday night, of course.

Will I be back for DSSG 2018 next year? I plan to be and would like to be. I’ve missed a grand total of one Deep South since 1992, and it’s unlikely I will quit now. And I feel in my gut that 2018 will be a better year for moi. I hope that turns out to be the case, but who am I kidding, anyway? Long ago, Barry Simon told me, “Look, you know we’ll all keep returning to Deep South like swallows to Capistrano as long as we are able.” I hope to do just that.

Postscript: Reinstalling Nebulosity and the Canon driver once we got home did indeed fix my problem, whatever it was. Murphy banished and the weather finally looking up, I find myself eager to do astrophotography from my backyard. In fact, I'm sanguine enough about observing again that I'm kind of looking forward to next year's Spring Scrimmage. PLEASE, NO MORE OF THAT JAMBALAYA, though!

Issue #531: The SCT Now

Issue #532: Astrophotography with Inexpensive German Equatorial Mounts

Issue #533: A New Way to Polar Align

Issue #534: Getting Your PHD

Issue #535: The Final Piece of the Puzzle

Issue #536: Deep Sky Imaging in Seven Easy (Sorta) Steps

Issue #537: The Novice Files: Star Charts Part I

Issue #538: Is This the End?

Issue #539: Get Thee to the Dark Site Part I

Issue 540: Get Thee to a Dark Site II

Issue #541: Taking Pictures with a C8

Issue #542: The Curious Case of the Schmidt Cassegrain Telescope

Issue #543: My Yearly M13 (from the backyard…)

Issue #544: To PEC or not to PEC

Issue #545: Good, Old EQ-6…

Issue #546: Two Down, One to Go...

Issue #547: A Losmandy GM811G Comes to Chaos Manor South

Issue #548: Astro-Video, Slight Return

Issue #549: Using the Losmandy GM811 for Visual Observing

Issue #550: Deep South Star Gaze 2017: You Can’t Win ‘em All…