Sunday, September 11, 2011

 

Me and Atlas


I was right put out, muchachos. After dusting off my DSLR to take a few pictures for a magazine assignment, the still-imaging bug had bit me again. I was all fired up to get out under the stars with my Canon Rebel, my StarShoot auto-guider, and my new 50mm guide scope. How the weather gods laughed! Amazingly, however, they decided not to prevent me from doing any observing at all, just any imaging, with drifting haze, temperatures near 90 at midnight, and humidity that made it seem as if I were looking up at the stars from underwater.

What to do? The simple solution was make it a Charity Hope Valentine night. I always have fun with my ETX-125, so that would have been OK, but my renewed obsession for DSLRing wouldn’t let go. OK, this would be the perfect time to give my Atlas mount a good shakedown before the coming of the fall picture-taking season.

I’m not sure why I haven’t written more about the Atlas, muchachos. Save for a couple of blog entries, I’ve had little to say about the EQ-6, even though we inmates of Chaos Manor South still refer it as “the new mount.” I was shocked to realize the other day that Atlas has been with us for going on four years. So it’s high time I said a little more about this classic of 21st century amateur astronomy.

It began for me in ought-seven, just as I was finishing up my last book. I needed a few more astrophotos for it, and while I could have used my Celestron CG5 German equatorial mount, I wanted to get the work done with a little more ease than it would allow. The CG5 can yield good guided (or even short unguided) images, but it’s never a walk in the park. Balance has to be just so. If you move to a distinctly different part of the sky, be prepared to rebalance. That is critical. And you will throw out at least a few sub-frames every time. It would be nice to have a mount that just got ‘er done, meeting my rather modest imaging requirements without a whole lot of fuss. The CG5 was also a bit light, even for the C8 at times.

Coulda had a Losmandy G11, I suppose. Why did I choose the Atlas—as the Synta EQ-6 is called by its sole U.S. vendor, Orion? I’d had a chance to play with a Chiefland buddy’s G11 with its Gemini go-to system, and I was not happy with what I experienced. The mount itself was a work of art given its relatively modest price, but Gemini? Did not like it. It was anything but user friendly, and I could tell I’d be re-learning its convoluted ways every time I used the thing.

Another plus for Atlas was EQMOD. Y’all know I love Celestron’s NexRemote, a telescope control program that takes the place of the hand controller and allows you to use a wireless joystick as your “HC.” Nothing like that for the Losmandy, but it turned out there was something just like that for the Atlas.

The EQ-6 is made by Celestron’s owner, Synta, but NexRemote is utterly incompatible with the Synta-branded mounts. Not only is the motor control firmware different, Atlas and his little sister Sirius (née HEQ-5) use stepper motors instead of the servos used in the Celestron gear. So, no NexRemote. But there was EQMOD.

EQMOD, which is currently being maintained and developed by the talented Chris Shillito, does many of the same things NexRemote does, if a little differently. NR is a standalone program while EQMOD is an ASCOM telescope driver. That is actually a plus in a way. Instead of just duplicating Atlas’ SynScan HC on the computer screen, EQMOD works with an ASCOM compatible planetarium program. Instead, for example, of selecting alignment stars from a list on a virtual hand control, you click on them on a planetarium’s sky display. Otherwise, EQMOD does pretty much what NR does—allows gamepad control, uses an off-the shelf GPS, allows you to compose sky tours, etc.

Was EQMOD what pushed me over the edge in choosing the Atlas? Almost…but…well…y’all know me. Price is always a concern for stingy old Unk, and, while the Losmandy was very reasonable at 3K, the Atlas was way more reasonable at about half that. I pulled the trigger. I figured that if the Atlas were half the mount the CG5 was I’d be home free.

It turned out the Atlas was more than half what the CG5 was in at least one regard: weight. Which I discovered when I came home to the old manse one winter afternoon and nearly fell over a pile of hulking boxes left in the front hall by the Brown Truck Dude. The longer of ‘em was obviously the tripod and was easily carried into the parlor. The little one must contain the HC, and the middle-sized carton the GEM’s head, since poor broken down old hillbilly Unk was barely able to lift it.

Opening said boxes revealed some pretty impressive stuff. Save for its head, the tripod was identical to what was on my CG5, which was a good thing. This 2-inch diameter steel leg thing is a decent compromise between “too weak” and “too heavy.” One thing I finally found out: the purpose of the indentation in the tripod spreader/eyepiece tray. It’s for a hand control mounting bracket, which is not included with the CG5 but is included with the EQ-6/Atlas.

The mount itself? Not just heavier, but bigger than it looked in its pictures (ain’t that always the way it is with astro-gear?). I mounted it on the tripod without incident, but lifting dang near 50-pounds to do that wasn’t much fun. I was impressed by the mount’s heavy build, but from the get-go wondered how often I’d be able to convince myself to take this thing to the PSAS dark site for a few hours of fun.

What else? There was the hand controller. Looking at its picture, you Celestron mavens are gonna think, “Man, it’s a NexStar!” It looks like one, yeah, but for better or worse it ain’t one. I grabbed the instruction manual, which turned out to be decently written if not perfect—like the CG5’s OK manual—and began to edumacate myself on what I was to discover are the decidedly different ways of the SynScan HC.

First tip-off to that was that while the keypad layout was very similar to the NexStar, the buttons were different. An example being the three “alignment” buttons at the top of both hand controls. Instead of the NexStar’s “Align,” “Enter,” and “Undo,” the SynScan had “Esc,” “Setup,” and “Enter.” Their functions are about the same as the three Celestron buttons, but in different order, which continues to give me headaches to this day. I am always pushing “Esc” (escape), which is where “Align” ought to be, with predictable results.

When I thought I more or less understood what the SynScan buttons should do, I fired up the mount and ran through a fake alignment indoors. You know: just accept whichever alignment stars the mount picks and see if it points in approximately the correct directions when you send it to objects. This is something I’ve done to familiarize myself with every new go-to I’ve used. Not only did Atlas do what he was supposed to do as far as I could tell, his steppers were far quieter than the CG5’s servos. No more “weasels with tuberculosis” sounds during slews.

The HC software? The alignment routine itself was just like that of the CG5 at the time: center three stars. I noted, however, that the SynScan HC did not have a built in polar alignment routine. At least not like the CG5’s, where the scope points at where Polaris (with the newer AllStar utility, almost any star) should be given a perfect polar alignment and you adjust mount altitude and azimuth to center the star. What the Atlas had (and still has) was a polar alignment borescope. I’ve heard rumors that the next iteration of the SynScan firmware will have an AllStar like polar alignment routine, but that ain’t happened yet.

Yeah, just a polar alignment scope, but what a polar alignment scope. This one has an eyepiece with an apparent field better than that of any polar alignment scope I have ever used. The HC has a utility to help you use this polar scope, too. After you enter time, date, and position, the HC will give the current hour angle of Polaris. Turn the mount in R.A. until the little circle on the borescope reticle where Polaris goes is straight down, and set the R.A. circle to reads 0 hours. Then, rotate the mount in R.A. until the “time” on the setting circle (inner scale in the Northern Hemisphere) is the hour angle given by the HC, adjust the altitude and azimuth of the mount to put Polaris in the reticle’s circle, and you have a very decent polar alignment.

Only deficiency I noted? Every once in a while Atlas would refuse to power up. I had enough experience with Synta/Celestron’s power cables to know that was the first thing to check. Sure enough, the connector fit too loosely in the receptacle on the mount. Closer examination revealed the connector pin on the mount side was in one piece, not two halves like on the Celestron gear, and could not be spread apart to create a firmer connection. I rummaged around in my junkbox and found a cable of the correct polarity that plugged in more firmly and the problem was banished.

Why buy from Orion? I emailed them about my cable problem and they immediately got a replacement on its way to me. I have little doubt their service is among the best in the business, right up there with the high-priced spread.

All that remained was to get the scope out under the sky, which I did when the clouds finally cleared off, about two fracking weeks after the Atlas arrived. Results? Mixed. I was not impressed by the SynScan HC. Go-to targets near the three alignment stars—the HC also offers a two-star alignment procedure—were in the field of a medium power eyepiece after a slew, but those farther afield were out; sometimes far out. I was also somewhat stymied by the mount’s altitude and azimuth adjusters. It was hard to move the mount to put Polaris where it ought to be.

The good news? When I fired up EQMOD, go-tos immediately got More Better Gooder, with everything somewhere in the field of my eyepiece from one side of the sky to the other. It was also cool to be able to use a wireless gamepad to move the scope and execute some mount functions, just like NexRemote. Overall, I was pleased. Yes, I was a little miffed about the HC, but from the start I’d planned to use EQMOD almost exclusively.

The real test would come when I got to a dark site—first light was at my buddy Pat’s substantially light polluted observatory—and took the pictures that were the main reason I’d shelled out the bucks for a new GEM. You can read about my adventure Down Chiefland Way in January ‘08 rat cheer, but to sum up: it was a little chilly for Florida, but the mount worked a treat. It auto-guided wonderfully well.

I didn’t know just how well until later, when I discovered that with my particular Atlas’ version of motor control board I needed to tweak R.A. tracking speed when using EQMOD. Much of the credit for the ease with which I was able to take pictures goes to the wonderful PHD Guiding software—it just locked on despite my motor speed faux pas—but Atlas certainly did his part. The combination of my Canon DSLR and Craig Stark’s PHD and his image acquisition/processing program, Nebulosity, was a winner. Hell, even the owner of a big AP mount and a high-falutin’ SBIG camera was impressed by what my humble gear produced.

I even conquered the mount’s main deficiency, its altitude and azimuth adjusters. The addition of a thin layer of bicycle chain grease fixed the azimuth friction. The altitude? There is no denying it is hard to raise the mount with its puny adjuster screw. People have even bent this bolt, the same one used on the CG5, in the course of polar aligning. I found a simple solution. Either do the polar alignment before mounting the OTA and weights or, when raising in altitude, give the bolt a little help by pushing up on the counterweight bar. Yep, just that simple. Adjusting for polar alignment still ain’t a joy, but it works and nothing gets bent.

After that? I did a couple more astrophotography runs with Atlas and my C8, Celeste, at the club dark site. Imaging with the DSLR’s comparatively big chip at 1300mm was as easy as rolling of a log. I put the SynScan HC in the case and left it there, just using EQMOD.

My picture taking for the book done, the Atlas rarely got used for the next two years. You see, I’d started this “Herschel Project” business, and when I wanted to use Celeste for that, the CG5 was more than adequate, including with the Stellacam shooting with the C8, bringing back dozens and dozens of faint and fuzzy aitch-objects every run.

In fact, I almost sold Atlas. Several months after I got the mount, Celestron released its CGEM, a modernized and prettied-up version of the EQ-6. It looked better, had better altitude and azimuth adjusters, and, most of all, used the wonderful Celestron hand control and software. Yeah, Atlas was about to go on the Astromart—till I began hearing about QA and other problems with the CGEM. I decided to stand pat.

Then, I started getting interested in DSLRing again. I also became curious about the SynScan HC. Surely it couldn’t be that bad? Why hadn’t I been able to make it work well? Wonder of wonders, Unk sat down and gave Atlas’ manual a thorough read instead of the brief scan it had got when I received the mount.

Apparently the problem was me, not the SynScan. Choosing alignment stars for this hand control is a different proposition compared to what it is with the NexStar. With the Celestron firmware, “good stars” are usually stars as far apart in azimuth as possible. The mount chooses the stars for you, anyway, so unless they are blocked by an obstacle and you have to pick alternates, it’s a no-brainer.

SynScan is different. The azimuth separation between the two initial stars matters somewhat, but what really makes a difference is R.A. For a good go-to alignment, the first two stars should be separated by at least several hours of Right Ascension. Third star? Not as critical, but it should be on the other side of the Meridian and between 30 and 70 degrees declination north or south.

The real kicker? The SynScan presents you with a list of alignment stars. B-U-T these are not given in order of how good they are. It is just a list of possible stars, and the first two in the list may be the WORST alignment choices for your time and date. You have to scroll through this list and pick three stars that meet the above requirements.

Sounded like I had done everything wrong when I’d initially tried the SynScan, and I couldn’t wait to give it another try—it would be cool to be able to use the Atlas without dragging out a computer every time. I got my chance one evening at the club dark site when I planned to use EQMOD to shoot some DSLR pictures for the first time in a long time. Naturally, the weather gods were not in favor of that, and soon sent drifting patches of clouds my way. Didn’t look like it would make much sense to set up the computer and camera, but there was enough clear (though hazy) sky for me to give the SynScan a try.

I did my best to choose three stars that fit the rules outlined in the manual: “Alignment Successful.” To M3 in the west. Centered in the field. M15 in the east? Boom! There she was. Well, holy cow. Yeah, EQMOD is cool, but sometimes simpler is better. Up and down checks on the SynScan? I liked the way it beeps to indicate when the slew is done, but I didn’t like the display’s orange backlight—even dimmed down it seemed too bright. I did like the fact that the backlight cuts off after you haven’t pressed a button in a while. I did not like having to press enter twice to go-to an object. In toto, not bad, not bad at all.

Last weekend I intended to get out and get my yearly picture of M13. As before, the weather gods were not amused. I knew before I left home that the haze, humidity and clouds didn’t spell “astrophotography success.” Y’all will be proud of me. I didn’t have a duck fit; I went to Plan B. This would be a good night to give the SynScan one last shakedown cruise in preparation for the (maybe) better skies of fall. And I had a theory I wanted to try out.

I’d heard on the danged Yahoogroups that a two-star alignment with the Atlas could sometimes produce an alignment better than a three star. If so, cool. Less work for me. I lugged the Atlas out to my new vehicle with the rest of my gear. That was the other reason I wanted to give the big guy a go: to see how easily I could load Atlas into my new truck, a Toyota 4-Runner, a.k.a. “Miss Lucille Van Pelt.”

Yes, I’ve finally accumulated enough astro-junk that my poor, beloved Camry has been outgrown. All the stuff went into the 4-Runner without a problem. There’s a lot more room, and the Atlas was significantly easier to load. He hasn’t got any lighter, but at least I didn’t have to lift him up over the lip of the Camry’s trunk.

Out at our Tanner-Williams, Alabama site, I was glad I hadn’t dragged out a lot of imaging gear. It felt as hot at sundown as it had hours before. Without all the camera and cable and computer stuff to fool with, all I had to do was get Atlas on his tripod, the C8 on the mount, plug in the HC and power, and plunk my netbook down on the observing table (I wanted to take another look at Comet Garradd, and would let SkyTools 3 figure out the coordinates for me. With everything ready to go, I fired up the Thermacell to chase the bugs, and sat down to wait for Polaris to appear.

When that star winked on, I powered up Atlas long enough to get the Polaris Hour Angle from the HC, adjusted the R.A. setting circle and the mount appropriately, and put the star in the little circle on the polar scope reticle. How accurate are these polar alignments? Undoubtedly not as accurate as a drift alignment, but neither do I think they are much worse than the computer alignments yielded by the Celestron mounts. By the time my fiddling was finished, there were obviously enough bright stars to allow me to complete the go-to alignment, too.

That alignment would be the two-star. I began it, picked two target stars that seemed appropriate, and had at it, centering the stars as the HC requested. The mount put the initial stars fairly close to the center of the Telrad reticle, and only a little fine tuning was needed. “Alignment Successful.”

How successful? Well, M3 was in the field if not centered. M15 was the same. So far, so good. Now for a test. Hardest thing for most go-to systems is objects fairly close to the horizon and away from the Local Meridian. Sagittarius’ M22 was both those things. Let’s go there. Crossed my fingers and toes and put a peeper to the eyepiece and saw—ABSOLUTELY NOTHING.

Well, well, well. What now? I didn’t have a big observing program to get rolling, and it was still very early…so how about an experiment? I’d power off, do a THREE star alignment, and go-to the same three targets. I took particular care this time, selecting Vega and Altair as my first two stars, they being well spaced in right ascension. For the third target, I picked Arcturus, which was on the other side of the Meridian and within the declination limits for the “cone” star. One thing I did notice? The scope stopped closer to all three of these stars, with the third one being just outside the field of a 12mm reticle eyepiece. “Alignment Successful.”

Alrighty then. M3? In the field and better centered than before. M15? Same-same. Now for the kicker, M22. Almost in the middle of the 13mm Ethos. I had to admit the three-star had worked better. I had been told that the three-star works best if your polar alignment is poor, but that does not seem borne out by my experience. My polar alignment was pretty good based on the high power observation of declination drift I did later. I intend to give the two-star another try sometime; it's possible my star choices could have been better, I reckon. Be that as it may, the go-to alignment yielded by the three-star was superb.

Every object I chose was in the field of the 13mm eyepiece, even with my Denkmeier Powerswitch diagonal’s reducer switched out and Celeste running at f/10. Yeah, the 100-degrees of AFOV does give you a lot of sky, but many of my go-tos were in the field of 80-degree AFOV 7mm at nearly 300x. Cannot beat that with a stick, muchachos.

The rest of the evening? A relaxing tour of cool deep sky objects on a hot August night. I let SkyTools take me through many of the Ophiuchus globular star clusters—except for that stinking 14th magnitude Pal glob, or course. From there it was on to whatever took my fancy. I also ran the “tour” the SynScan generated for me. The Atlas effortlessly took me to at least 40 marvels. After a while I began to get put out when I had to occasionally switch in the reducer to bring my target into the 7mm’s field. Yep, that good and I was already taking it for granted.

With Sagitta finally up out of the light dome I wanted to have another look at little Comet Garradd. He will be with us for a long time, but I was anxious to see this brightening visitor again. The question was how to do that. With the Celestrons you just enter the coordinates into “Go-to R.A./Dec.” Quite a bit of fumbling around with the SynScan failed to reveal a similar function, however.

Till I came to “User Objects.” Entering the comet as a user-defined object wouldn’t be as easy as just going to a right ascension and declination, but I thought it would be workable. One good thing was that the procedure was easy to figure out; I didn’t have to drag out the manual, thank god. Coordinates in, I punched enter and the Atlas hummed his unassuming hum.

When he stopped, I inserted the 27 Pan and had a look. There was the comet, not only showing a nice oval coma and a starry nucleus but a small, barely visible tail spread across a rich background of stars. I put Garradd at just a little dimmer than magnitude 7. If he’s this good now, what will he be like at his height in a few months? I think we got us a good one, folks.

Just after 11:30 p.m., the rising of an old Moon and a fresh bank of clouds led me and my buddies to pull the Big Switch. Was I satisfied? And how. I’d seen a lot excellent DSOs and had proved the SynScan HC’s reliability to my satisfaction. I have no doubt that once we get some clear sky I will have a real good time taking some of my humble “Instamatic astrophotos”. Will I still use the CG5 more, even now that I am happy with the Atlas’ HC? No doubt. It’s just too easy in every way. But when it’s got to be done right, the Atlas’ steady shoulders are up to bearing the load.

Next Time: My Runs

Comments:
Hey Unk, the G11 absolutely can be used with a wireless joystick - via the good old ASCOM Gemini driver.
 
I acquired my Atlas several months back and have been nothing but satisfied. Then again, I upgraded from an LXD-75 which leaves a lot of room for improvement.
On the downside, weather has kept it packed away since June. I hope to run it through its paces atleast once before we head to CAV in October.
 
I have a Sirius mount, which is similar but has a lower weight limit. I mount my C8 on it. I've enjoyed it a lot over the years.
 
This explains a lot....

My first try, right out of the box(es), with my new EQ6 was amazing. Gotos were spot on through a 20mm with a C9.25 at F/10. My second, third, and fourth nights out and my gotos were way off. I couldn't understand it. I did everything I had done on the first night to begin with proper balance, polar alignment, and making sure to finish centering to compensate for backlash. This reminded me that I had forgotten one minor detail. That first night the stars I could use just happened to fit the parameters of works best for the Atlas and not what the hand controller suggested. The other nights, having gone to an area where much more of the sky was visible, I just followed the controller's suggestions. Ooops. Thank you for this!
 
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