Wednesday, January 09, 2008
Down Chiefland Way with EQMOD
Actually, this entry ain’t really about the Chiefland Astronomy Village, though those of y’all who’ve been reading this blog for a while know the high regard Your Old Uncle Rod has for the skies—and the people—of CAV. No, this is really about the new telescope mount that has come to stay at Chaos Manor South, the Orion Atlas EQ-G. Well, that ain't quite right, either. It’s really about an amazing piece of astronomy software, EQMOD, which turns a good mount into a great one.
In recent times I’ve begun to drift away from the fork mounts I’ve used for the better part of three decades. That process began with the arrival of the Celestron CG5 at the ol’ manse three years ago. Despite its low price, this German Equatorial Mount worked impressively well, displaying surprising go-to accuracy (at least as good as the NexStar 11). It also seemed easier to use for imaging. The silly little thing took picture after autoguided picture with an SBIG camera. Couldn’t ask for more? Actually, I could.
One weekend I was down at Chiefland with the C8/CG5 and a Stellacam II, traveling light. I was having a great time videoing the deep sky…until. The wind came up. With a good wind (not quite a gale by any means), the CG5 began to shake like a sinner in the hands of Elmer Gantry. Removing the C8’s dew shield helped some, but not quite enough. Despite the fact that this was the only time I was totally skunked, I decided another GEM for the C8 was in order. Something with a little more heft. At least for those times when I want to do long-exposure prime focus imaging.
What to choose? I eliminated the high-priced spread, the APs and Bisques and MIs, right off the bat. I do dream of a Paramount occasionally, but that will wait for retirement. Next tier down? Even the CGE and the G11 seemed a mite rich for my blood at this juncture considering the “huge” amount of spare time I have to actually observe with the C8. Vixen Sphinx? In my opinion, that is getting down into the “too-light” range again.
Which left the Synta EQ6 SynScan go-to (a.k.a. the Atlas EQ-G for us Americans). This looked to be a nice, big (and heavy at 40 plus pounds for just the GEM head) mount for an impressive price, about $1500.00 with a go-to hand controller from the U.S. distributor, Orion. I chose the $1500.00 version with the HC despite the fact that the identical (including electronically) mount is available without the hand control for 300 bucks less. This would have been a viable option for me, since, you see, I didn’t plan to use the HC all the time—or most of the time—for go-toing. I did think it would be nice to have the hand control for those occasions when I didn’t want to carry the laptop and EQMOD into the field.
When the Atlas arrived at dear, old Chaos Manor South, naturally so did the clouds. I did have the opportunity for a few outdoors tests after Christmas, but these were limited. Most of my testing was done in the living room, but allowed me to check that both the mount and EQMOD seemed to work fine.
EQMOD was remarkably simple to get going, and, other than a wireless gamepad (a generic one works fine), it only required the purchase of two inexpensive additional items: a serial cable and the EQDIR interface module from Shoestring Astronomy. EQDIR ($35.00) is a small electronic widget that plugs into the laptop’s serial port (or a USB – serial converter cable); the serial cable plugs into EQDIR, and the other end of that cable is connected to the mount’s DB9 hand control connector (yep, DB9—none o’ that RJ nonsense for big dog Atlas). What EQDIR does is translate the serial-speak coming out of the laptop into the mount-speak Atlas understands. Like every Shoestring product I’ve used, it works like a champ.
If the Possum Swamp skies wouldn’t cooperate, what could old Unk do? Grab my trusty 1995 Ultima 8 OTA and the new Atlas and head down to Chiefland, Florida, that’s what. In addition to checking-out the mount, I was hoping to get a few DSLR images for my new SCT book. That in mind, I packed a ton o’ gear into the Camry and lit-out for CAV (for Unk, “roughing it” in Chiefland means staying at the Holiday Inn Express, which is maybe 15 minutes from the observing field).
Arriving at the little town after 6 and a half hours or so on I-10 and (partially) scenic Highway 19, the Florida - Georgia Parkway, I checked into the Holiday Inn Express and headed for the storied observing field. I was pleased to see that five or six other hearty souls had joined me for a weekend on the slightly chilly post-Christmas observing field.
In short order, I had the mount set up and EQMOD ready to roll. Actually it was not quite that simple. There's the EZ Up tent canopy, the camp table, the Toshiba laptop, three or four gear boxes, a sizeable eyepiece case, batteries, extention cords, and the other numerous and sundry items I always bring along. There was also the USB cable to the Canon 400D, the DSUSB interface box and connection to the camera, the Shoestring GPINT-PT module and the ST-4 style connection to the scope, the PhD Guiding program, and Nebulosity for camera control and image acquisition. Those things would wait for night two of my two night (wished it coulda been three) Chiefland adventure. I intended to devote night one to the mount and EQMOD and night two to picture taking.
Set up on the field, there was still an hour or two to go before sunset, so I made tracks for the Chiefland Walmart for a few items. One of which was bottled water. Even when it is cool, you have to keep yourself hydrated. You may not feel too thirsty, even if you begin to get dehydrated, but your get up and go, you will find, will have got up and went--your stamina will go out the window. Other than that, just the usual items: Jack Links Jerky and granola bars for midnight snacking, Monster energy drinks to refuel myself as the clock ticked toward morning, and bottles of Guinness to supplement the Rebel Yell back in the room after the run.
Back on the field with the Atlas and C8 uncovered, one thing that blew me away? I considered the Atlas a bargain mount, so it was a real eye-opener to see how big its mount-head looked compared to Carl Wright's nearby Celestron CGE. Hell, the Atlas dang near dwarfed it. Heft is good, but is no guarantee of precision when it comes to mounts, of course. That’s measured in go-to accuracy and periodic error or lack thereof. The details of the mount's PE characteristics, like the minutiae of all the gear and software mentioned above, is perhaps a subject best left for another installment. But even without talking arc seconds of error, the way a mount acts when its told to go-to something and what happens when you give the scope a sharp rap upside the head—err “OTA”—go a pert smart distance in telling what the mount’s made of, so to speak. As would become evident after just a few hours of use, this is one heavy mutha, in every way.
Despite my at home tests, I was a bit skittish about the EQMOD software, and decided I’d devote most of the first night to getting comfortable with it. Needn’t have worried. If anything, it’s even easier to get going than NexRemote, which ain’t no slouch. Start out with Atlas in its normal Home Position (counterweight down, tube pointed north). An at least halfway decent polar alignment should have been done via the built-in (and excellent) polar scope. With the mount connected to the laptop via the serial cable and EQDIR, start-up the planetarium program of choice. That can be anything as long as it is ASCOM compatible. I chose the new beta of Cartes du Ciel, a solid and wonderful (and FREE) program I’ve used for years. Why didn’t I use my “usual,” TheSky 6? Tests showed a few problems between EQMOD’s driver and TheSky. Note that this is the only even marginally ASCOM compatible program I found to have difficulty with EQMOD, and that by tinkering with their computers folks have been able to exorcise these gremlins.
Anyhoo, start up Cartes or whatever, hit “connect to scope,” and choose EQMOD as the scope/driver. Up pops a driver window. Hit the “setup” tab and enter the usual stuff any ASCOM driver will want to know--like latitude and longitude. Do make sure these values are the same as those in the planetarium. If’n you don’t, the mount will act squirrelly—as Unk’s did on the first night out in the backyard with the Atlas till he discovered EQMOD had the coordinates of Manila, not Possum Swamp.
Data entry complete, this is where things get right interesting. It’s time to do a go-to alignment. Still in “setup” on EQMOD, click “n-star” alignment. What that means is that you are a-going to align on three or more stars (there is a one-star option that can work well if the mount is accurately polar aligned). A window will pop up with buttons that allow stars to be accepted and the alignment ended when all the stars have been centered. There are also directional buttons that can be used to move the scope to point at chosen alignment stars. If you’re like me, though, you’ll be using a wireless gamepad. One of the joys of EQMOD is that it will work with almost any joystick or game controller including the 10 buck wireless job I picked up at WallyWorld. Next step is to choose some alignment stars, and that’s where EQMOD takes a different path.
Rather than choosing stars from a list on a real or virtual hand controller, with EQMOD you click on stars shown on the planetarium program’s screen—any stars. Select Capella, click “slew to object,” and off the scope goes. When it stops, center her up and click the button on the gamepad that maps to “accept star” (there’s a utility in EQMOD’s set-up that allows you to assign gamepad button functions as desired).
When the Atlas stopped at the first alignment star, a look through the finder showed Capella was just a degree or two away. My next two stars, Castor and Rigel, were not just centered in the finder; they were in the C8 eyepiece at 100x. When these stars are centered and accepted, hit the gamepad’s “end alignment button.” How many alignment stars? I did three on the eastern side of the local meridian and quit. According to Mon, best results are achieved if three on the east side and three on the west side of the meridian are used. Being lazy, I just left it at three.
Results? Anything I asked for from horizon to horizon was somewhere in the field of a 12mm Nagler. I have no doubt that if I’d done more stars performance would have been even better, but this was more than good enough for visual observing and for imaging with the Rebel XTI. Alignment done and time to go-to something? No problem. Just click on an object, any object, on the Cartes du Ciel screen and select “slew to.” Away she goes and said object is in the eyepiece. Simple, easy, sweet.
If all EQMOD did was allow the mount to do accurate go-tos, it would be impressive, but it does a heck of a lot more and features are being added all the time. There’re already add-on modules for things like PEC recording and refinement, and a Tour sub-program that’s intuitively easy to use. One of the things next on the EQMOD feature agenda is a polar alignment utility that should allow most astro-imagers to forego drift alignments. Got any ideas of your own? Mon and company are more than open to suggestions and are found constantly inhabiting the Yahoogroup devoted to their program.
How was the mount mechanically? I gave the C8 a slap and she barely moved. It was almost as if Atlas were grinning—smirking—at me, “What did you think, you gull-derned redneck, that I can’t handle a measly C8?!” Summing up…by the end of the first evening I was convinced the Atlas is a heck of a lot of mount for a heck of a few dollars. To really prove its worth, however, Atlas would have to show me he was up to the very difficult act of taking long exposure deep sky images. That was next evening, though.
This evening? After observing a goodly number of deep sky objects--off a list of 100 "best of the best" I am working on, perhaps as the basis of a new book project--the clock was creeping on toward three a.m. The night had been a long one due to the early sunset, and I was tired before I got going from the drive down and setup, so I was slap amazed to have made it so late. I reckon I was mesmerized by Atlas, purring like a big cat as he hefted Celeste, my C8, to target after target. Out to the car parked on the access road so as not to disturb my fellow observers, and back to the motel in two shakes.
In the morning, I filled up on the Holiday Inn Express' biscuits and sausage gravy till I derned near made myself sick, and returned to the room to try to figger out how to make the day pass. Despite my late, late (or early-early) evening, I was up not long after 8, since I am so used to getting up early for work. Winter sunsets come early, however, so the wait for darkness is not intolerably long, and I filled the day by writing, reading the latest issue of Sky and Telescope, and surfing Cloudy Nights on the laptop. A late lunch at the neighboring Taco Bell, and it was actually time to start thinking about heading to the site.
Out there, I shot the breeze with a fellow astrophotographer, who, with his SBIG and his T-Point and his AstroPhysics mount, was way out of my humble league. He approved of my Atlas/C8 setup though, and especially my Canon 400D Rebel, opining that if your main interest is pretty pictures, there's really no reason to use anything other than a DSLR these days.
Be that as it may, I got my Canon set for its first astro-imaging run. Ran up EQMOD, aligned on the same stars as the previous night, removed the diagonal and visual back, and configured the scope and camera for prime focus imaging. To that end, I mounted the camera on the C8 behind the f/6.3 reducer/corrector by means of a T-ring on the camera and a standard SCT prime focus adapter on the scope. Gotta connect all them wires, of course, which meant running USB and shutter cables to the camera. Shutter cable? Current DSLRs require you to have a remote release to do exposures longer than 30-seconds. The DSUSB box/cable I got from Shoestring Astronomy takes the place of that and allows my imaging program of choice, Nebulosity, to operate the Canon much as if it were an astronomical CCD camera.
There was the guide scope, too, of course. For me that is a 66mm William Optics SD refractor. Which guide camera? At the moment I am using my Meade (original color) DSI camera. Since it doesn't have a guide output to allow me to connect it to the Atlas' autoguide port, I use another Shoestring adapter cable, which runs from the computer's parallel port to the autoguide port and provides standard ST-4 guide signals. The guiding software I am using is, as I mentioned above, Craig Stark's PHD Guiding. "PHD" stands for "push here dummy" in this case, and that is really what is.
Fired up Nebulosity, and then back to EQMOD to slew the scope to the evening's target, M42, natch. It's big, it's colorful, and it is bright, perfect as a first subject for a new camera. When the Atlas/EQMOD beeped, I set the exposure in Neb to 2-seconds and mashed the "frame and focus" button. Shortly, an out of focus something appeared on the laptop screen. I focused carefully, making the stars as small as I could make them, and then switched over to "fine focus" mode. Click on a star on Nebulosity's display, and it is zoomed in. By observing this blown-up star and the graphs Nebulosity provides, it is easy to attain perfect focus. Viewing your camera's images on a big laptop screen is much easier than squinting through the tiny, dim viewfinder of a DSLR.
Now for the guider. I lit off PHD, set it to looping 2-second exposures, and focused till the stars looked good and small. I hit "Stop," clicked a likely looking star, and mashed the Guide button. PHD calibrated, moving the star in all four directions to gauge how the mount reacted. I was gratified the Atlas displayed little or no backlash in declination--my CG5 has a bunch. When it was done with the calibrating, PHD immediately and automatically started guiding. That's all there is to it, loop exposures, stop, guide. It really is "push here dummy."
Back to Nebulosity. I set up a series of 20 three-minute exposures, hit the start button, and "Neb" started doing its thing. PHD was, as I could see when the first sub came up with nice, round stars, locked on. There was literally nothing for me to do while the exposure series was in progress. So, I wandered around, talking to/annoying my fellow observers, ducked into the Clubhouse to retrieve a Monster, and, generally, just cooled my heels until, somewhat more than an hour later, the series was done.
By the time my second M42 series finished it was midnight. I was tempted to go on to a second target. B-u-t. There was the dreaded packing and drive home in the morning. Even if I had decided to go longer, Urania said "no" and closed down her sky soon after my last M42 sub-frame completed. As is often the case this time of year at the CAV, ground fog was creeping in. I managed to shoot the last couple of frames through the fog, but ten or fifteen minutes after the last one finished, another mess of fog rolled in, covering the scope, blocking the sky, and causing me to pull the Big Switch. Shoulda planned for a third day at CAV but that's the way the cookie crumbles, y'all. By the time I packed up and got back to town it was well after 1 a.m., so it was time to quit, fog or no fog, I reckon.
Back at the Holiday Inn Express, I couldn't resist taking a quick peek at some of my subs. They looked darned good, even without processing. Most amazing thing? Nebulosity was wonderful. EQMOD was wonderful. The Atlas was wonderful. The Canon was wonderful. Most wonderful was PHD Guiding, though. As above, it just LOCKED ON. Still, I didn't realize just how good a job it had done for some time. Later, I discovered that, due to a peculiarity in my model of Atlas' motor control board, when you use the mount with EQMOD the RA speed needs to be adjusted slightly (in EQMOD) for correct tracking. I didn't know that and hadn't done that. PHD didn't care. It gave me round stars, anyway. Yeah, amazing.
I toasted Mr. Stark's amazing programs with some Yell and a Guinness or three, watched a few minutes of the somewhat odd, somewhat silly Ghost Hunters on the dadgum teevee, and fell into a deep sleep ruminating on how preposterously cool it was that the new Atlas and all the other new gear and software has worked perfectly the first time out. Sometimes you get lucky, muchachos, sometimes you just get lucky.
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Looking good, I guess I wasn't the only one who got an Atlas EQ-G for Christmas. Took the ole PowerStar 8 off the forks and as you say,it's like a rock now. The shoe string interface works just great. I only wish the skys would clear up here in Oregon, so I can use it. Thanks for the simple to follow alignment information.Post a Comment
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