Sunday, October 21, 2012
Unk’s Yearly M13
Weekend before last’s dark of the Moon observing run? Let’s just say Murphy ran rampant, muchachos. Your poor old Uncle’s rather modest plans came to naught. Not that there weren’t any amateur astronomy related goings on at all. Miss Dorothy and I traveled to Pensacola, Florida to spend some time with our old friends Doc Clay Sherrod and wife Patsy and to hear Doc’s yearly talk for the erstwhile Escambia Amateur Astronomers’ Association (EAAA). Clay’s talk on the Mayan calendar and the 2012 business was excellent, but that was the only successful amateur astronomy we did that weekend, which was a problem...
With the year two-thousand and twelve beginning to wind down it was past time for one of your old Uncle Rod’s annual traditions. No, I ain’t talking about my Christmas Eve peek at the Orion Nebula. What I am referring to is another tradition and resolution: that if I don’t do anything else astrophotography-wise over the course of a year, I will at least take a picture of M13, Hercules’ Great Globular star cluster.
It ain’t like I am exactly overwhelmed by the number of opportunities to do honest-to-god imaging down here in The Swamp. Couple my natural laziness with my wide array of astronomical interests and the usually poor Possum Swamp weather—it has been particularly bad this year—and months and months sometimes goes by without me opening a shutter. But I still want to keep my hand in, and thus was my yearly M13 born. I figgered that resolution would ensure I got out with the gear at least once between late spring and mid fall.
|On 35mm film.|
Aside from the mis-focus, there is a little star trailing, too, even though I did my best to guide (manually). I didn’t drift align; as usual I was in a hurry to get something before the weather shut me down. I just used the polar alignment reticle on the U8’s finder scope, and while that was OK, there was detectable field rotation over the course of the lengthy (by today’s reckoning) exposure M13 required.
Starlight Xpress MX516
Shortly after this new century began, I decided it was time for me to join the CCD revolution like some of my Bubbas. I was attracted to Starlight Xpress’ MX516 for two reasons: it was slightly cheaper than the equivalent camera from SBIG and it featured self-guiding. Using an interlaced chip, the camera devoted one field to guiding and one to taking the picture, alternating between the two tasks. That meant I could guide through the imaging scope and not worry about a guide scope or off-axis guider.
|Starlight Xpress camera.|
If I’d a-had good sense I would have bought Celestron’s new NexStar 8 or at least a set of digital setting circles before a CCD camera. I haven’t made too many Bad Mistakes in amateur astronomy over the years, but that dern shore was one.
I sold the MX516 on the pea-picking Astromart after a couple of years of struggling. It was 2003 and I needed a camera, preferably a color camera, to capture the greatest Mars opposition of me or anybody else’s lifetime. I’d gotten some OK (monochrome, natch) shots of Jupiter with the MX516, but I well and truly ready to be done with it.
What I wound up with was the SAC 7b, a cooled color camera from a tiny outfit down in Florida. The story of the SAC cam and its maker is probably a worthy subject for a blog entry someday, but, to cut to the chase, the SAC 7b worked phenomenally well on Mars and Jupiter and the Moon and Saturn. On the deep sky? Not so much. It was nothing more than a long-exposure-modified and gussied up webcam. Still, despite a chip even smaller than the one on the MX516, I was able to get some recognizable deep sky images, including one of M13 one early fall night.
I’d been studying Meade’s advertisements for their new CCD cameras for a couple of months. This “Deep Space Imager” looked interesting (assuming I wasn’t just reading more Meade hyperbole): easy to use, color, an at least somewhat larger chip than the ones on the SAC and the Starlight Xpress, no need to worry about cooling since it didn’t need to be cooled. Less than 300 George Washingtons was the entry fee, which got my attention, you betcha. I hesitated, but, dang it, that CCD revolution was passing Unk by. Yes, I’d done some good planetary work with the SAC 7B, but that wasn’t like doing deep sky shooting with a real CCD.
One thing that really helped me get the DSI going when it arrived was software that, as I have written before, while a little complicated, did everything in automated fashion. Instead of, for example, leaving it to your discretion to take dark frames, the DSI software, Envisage, reminded you to, prompting scatter-brained ol’ Unk to cover (and uncover) the scope’s aperture. What also helped a tremendous amount was my new CG5 mount.
|With Meade's original DSI--finally making a little progress!|
The Celestron CG5—which I still have and use—was easy to polar align with a built-in routine in its hand control, and go-to meant I didn’t have to struggle with flip mirrors or other foolishness to get my targets in the small field of the DSI. If something didn’t wind up in the frame after a conventional go-to, I could engage Precise Go-to mode, which would put the target on the DSI’s chip every stinkin’ time—after a short stop to center a nearby bright star. The CG5’s gears were good enough for me to do unguided 30-second shots with the C8 at f/3.3. Yay! No guiding!
My initial results with the DSI were not pretty, even by my humble standards, but they were OK and much better than what I’d done with the MX516. One early June night in 2005 that for some weird reason turned out semi-clear, the shots began to roll out of the little camera: M57, M10, M12, M5, and, yes, M13. My focus was slightly off, my processing was wrong-headed, and I didn’t know how to get rid of the background color gradient caused by the light pollution at my club’s in-town observing site, but it was a first step. It heartened me, and on that night I decided to remain in the ranks of the CCD army, even if I was in the rear guard.
After a year or two of getting my feet wet with the DSI and coming to believe there was something to this CCD business after all, I was lucky enough to move up to a big boy’s camera, the (black and white) SBIG ST2000. In one fell swoop I went from the teeny-weeny DSI sensor to a 1600x1200 Kodak chip. Not only was there cooling, there was regulated cooling, which some of today’s cameras don’t even feature—set the camera for a chosen temperature and it would keep the camera at that temperature. Oh, and there was a second, smaller CCD chip onboard for SBIG’s proprietary self-guiding system.
Hoo-boy. That was a lot of new stuff for CCD fumbler me to grok. The larger CCD chip helped both in framing bigger objects and finding smaller ones. I didn’t have to use Precise Go-to anymore. But I had a lot to learn. Starting with the fact that if you used an f/3.3 reducer on your SCT with the 2000 as I sometimes did, you would see one hell of gradient from light pollution and vignetting. It was easy to banish that with a flat-field frame, but I had to learn how to take those. The self-guiding system seemed like a dream come true—no guidescope or off-axis guider from Hell required—but it was dang sure not as easy to get working as I had hoped.
That was not so much because of the camera, but because of its software. I had both the software that shipped with the ST2000, CCDOps, and the step-up program from Software Bisque, CCDsoft. CCDSoft gave me fits, especially with its guiding calibration routine. Basically, there were two choices: recalibrate the guider before every exposure, or enter your declination in the guide window, which would supposedly allow you to skip further calibrations. Unfortunately, entering declination of the current scope position didn’t seem to help. My guiding was putrid unless I did a new cal. If I were able to successfully complete a calibration. It failed more often than not, and it wasn’t always clear why.
I finally settled on calibrating before each shot, not that big a deal, and, gave up on CCDSoft and just used CCDOps, which seemed easier to use if not nearly as full-featured. It was more prone to completing guider calibration successfully, too. One thing both these programs did? Give me a better appreciation of how good PHD Guiding is.
The above might lead you to think I had nothing but bad luck with the ST2000. Quite the opposite; I had very good luck with it. As soon as I had an idea of how to proceed, the 2000 began cranking out images like this annual M13. Yes, the core is blown out and it’s a little too contrasty, but the stars are round and small. I still like it. AND the camera managed this with my humble CG5 German mount, which it had no trouble guiding as long as I kept the balance right.
So why haven’t I used the cotton-picking 2000 in a couple of years (at least)? First, as always, I want color. Yes, I could get color with the ST2000 via multiple exposures through filters, but trying to do that in the (not bad but not insignificant) light pollution of my dark site would likely be a challenge for image processing challenged me. Also, my opinion is that a real CCD camera is probably best for folks who have observatories, or who at least can roll the scope out. Doing flats, for example, is an absolute pain when you have to re-do them every single time because you have to take the camera off the scope and pack everything up.
Still, I may get back to the SBIG before long. It would be nice to use a cooled camera when winter goes and spring comes. My DSLR does fairly well on warm nights, but I’d be a-lying if I said I wasn’t troubled by noise on hot nights down in the ol’ Swamp. I do plan to make some changes to make the 2000 more pleasant to use: I’m going to forget the self guiding and just go with PHD and my StarShoot autoguider. Since I won’t be self-guiding, I’ll be able to use the wonderful Nebulosity 3 to run the camera. And if I stick to the f/6.3 reducer, I’m thinking Gradient Xterminator might allow me to forego flats.
Canon Rebel Xti (400D)
I loaded up a passel of gear: Atlas, C8, computer, guidescope, etc., etc., and headed for the Possum Swamp Astronomical Society’s storied dark site. Got set up. Guzzled a Monster Energy Drink. Took a few snapshots of the field and my new PC setup with my little Fuji Super-zoom camera. This time out, I placed the PC and its ancillary equipment in the back of the 4Runner, Miss Lucille Van Pelt, rather than using the camp table and computer shelter. Less stuff to worry about, and I hoped the PC and everything else might stay a little drier when heavy dew began to fall. Worked great.
But that was the only thing that worked great. Fired up the Atlas and EQMOD on the laptop. Got out the game pad I use as my “hand control.” Tried to slew the scope to put it in position for a borescope polar alignment. No workie. A look at EQMOD’s joystick setup screen told the story: The Toshiba laptop is fairly new and I’d never got around to setting up the gamepad and assigning the many EQMOD functions to its buttons. Wasn’t about to try to do that on a dark field. Drug out the SynScan HC.
The alignment went OK, with M13 being in the field when I went there. Hokay, get PHD Guiding and the guidecam, my cool little StarShoot autoguider, focused. Hmm. The stars in M13’s field seemed dimmer than I remembered from last time. Whatev. Mount the Rebel and focus up. What the—? l Not only was there no M13 visible, none of the relatively bright stars in the field showed up either, even when I upped the exposure and slewed around a little bit. Puzzled, I looked up to see clouds. Lots of them. I gave it another hour, but at 9:30 in the fracking evening I packed up and headed back to the Old Manse since it had become evident I wouldn’t be even get any visual observing done.
One thing was clear, if I was to get this year’s M13, I would have to get a move on. My last decent no-Moon opportunity to try for it in 2012 would be on Saturday 13 October; by the next dark of the Moon it would really be low. The weather, as is par for the course down here in October, continued to be unsettled, and I wasn’t about to drag a ton of stuff out just to be skunk bitten again. I also thought that even if I had to shoot through haze the Xtreme might still bring home the bacon.
I headed for our Tanner-Williams, Alabama observing field a little later than I should have Saturday afternoon, but I wasn’t worried. Yeah, it takes a fair amount of gear to run the Xtreme—computer, monitor, DVR, cables—but still considerably less than what’s needed to go DSLRing. What did worry me was the bands of clouds in the west.
Didn’t take that long to get Celeste, my C8, on her CG5, the Mallincam connected, and the computer and video display set up in the back of the 4Runner as I had the Saturday before. Turned out all my worries were groundless. Despite arriving at the site later than I usually do, after set-up I still had to cool my heels for a while before the bright stars winked on. And the clouds that had concerned me looked to be scudding off to the east.
Soon as there was a goodly selection of alignment stars, I fired up the CG5. I was using the hardware hand paddle this time out instead of running the mount with NexRemote. I love NR, but using the NexStar hand control cuts down on the gear burden and is a little quicker to get going. Powered up the Xtreme, told it (via the Mallincam software running on my Asus netbook) to draw crosshairs on the screen, and got started. Did a 2-star alignment followed by 4-calibration stars, ran the (old fashioned point-at-Polaris) polar alignment routine in the hand control, and re-did my 2+4.
The last two cal stars landed in the field of the Xtreme, so I thought my alignment would be good enough, despite my realization that I’d forgot the Up and Right Rule. For best results with the CG5, always center the alignment stars using the up and right keys on the HC only (use the other keys to position the star so you can center the stars with up and right). The CG5 has plenty of declination backlash, and up-and-right-only helps the mount deal with that. My R.A. balance was off, too, judging from the sounds the CG5 was making, never a good thing for go-to accuracy.
Mashed the keys to send Celeste to M13, and held my breath for a minute. The CG5 has been uber-reliable over the seven years I’ve had it, but I am used to computers pulling their little practical jokes on poor old Unk in the middle of the night on a dark observing field. Not this time. When the motors stopped their weasels-with-tuberculosis sounds, M13 was in the frame. Not centered, but in there.
Wheeew! Focused up with my JMI Motofocus—which I would not live without for imaging of any kind—set the exposure to 14 seconds (7 would actually have been enough), and pushed the button to start my Orion StarShoot digital video recorder rolling. That little thing is one of the best buys I have made in quite a while. It is considerably smaller than a pack of cigarettes and will go all night on an 8gb SD card and its internal battery.
Talk about easy to use, too: pushing and locking the StarShoot DVR’s one-button wired remote will turn it on and start it recording. Release/unlock the button and it will stop and turn itself off. I still focus and frame using my ancient portable DVD player (I use a cast-off cable TV switch box to send video to either the recorder or the DVD player as necessary), since the display on the StarShoot is a little small for my old eyes. Back home, I can either output NTSC video to a DVD recorder to preserve my “masterpieces,” or connect the recorder to a computer and drag the night’s video files to my hard drive. Simple and sweet and the video looks very good, even on our big-screen LG TV.
So how’d I do? See for yourself (above). No, the Xtreme cannot compete with a DSLR for prettiness. But its results are at least as good as my early attempts with the Meade DSI, and it sure is easier to use than either. No guiding. No dark frames. Just turn on the camera, slew to your target, adjust exposure and other settings to suit you, and do a little recording. When doing The Herschel Project, I found I could easily record 100 objects over the course of a short PSAS observing run, and upwards of 200 on a long night at the dadgum Chiefland Astronomy Village. I was happy and satisfied when this year’s M13 flashed onto the big screen at home.
When M13 was in the can, I found to my surprise that the skies were still acceptable. The last of the clouds had scudded off, and while it was very damp it was not unpleasant. What to do? First I took a couple of videos for The Herschel Project Phase II as part of my quest to get better looking color pictures of some of the more spectacular H-objects. After that, I just toured the best of the best of the fall sky. The standout was probably The Sculptor Galaxy (a.k.a. The Silver Dollar Galaxy, a.k.a. The Golden Galleon Galaxy), NGC 253, which stretched all the way across my monitor and showed a lot of detail despite being way down in the Possum Swamp light dome.
Another target Saturday night was the current comet de jour, Hergenrother (168/P). It’s caused quite a sensation in our ranks in a small way. Probably because we’ve been experiencing something of a comet drought over the last year. It looked good in the Mallincam, sporting a pretty—if small—tail. I did think it was a little disappointing in a buddy’s 15-inch Dobbie. Considerably dimmer than I expected, maybe magnitude 11 rather than the 10 I’d been hearing about on the Internet amateur astronomy boards.
Hergenrother’s dimness may have had more to do with the heavy haze that was coming and going than this cute little comet’s intrinsic brightness, but if you haven’t seen it, better get out and take a look now. The Moon is on her way back and the comet only looks as good as she does now because of an outburst—weather made me miss Hergenrother’s outburst peak of near 9. I suspect the comet has begun to fade already and will soon be on her way back to magnitude 15 or dimmer where she would normally be.
After the comet was recorded, I took a second "insurance" M13 sequence, and did some more hopping around. What finally shut me and my pals down was not the return of the clouds, but the extremely heavy dew. I’ve seen it worse in late October, but not much worse. By the end of the evening Celeste’s OTA was raining. I finally pulled the big switch about 11, and when my mates saw what I was doing they decided that looked like a good idea and threw in the cotton-picking towel, too. Soon enough I was back within the comforting walls of Chaos Manor South reviewing the night’s videos on the TV in the den while sipping, err, “sarsaparilla.”
And that was that for another year, muchachos. 2013’s M13? Oh, I would be lying if I didn’t say I have big plans for it, as usual. Maybe a tricolor exposure through the SBIG ST2000. Ground truth, though? Given my weather and my skills, all I can promise is that I will come back with something. Sometimes, like this year, that is just good enough.
Next Time: Amateur Astronomy and Amateur Radio Redux...
I am very lucky I have observant readers like you, Matt, to keep confused ol' me on the strait and narrow! :-)
As a neophyte to astronomy, I needed something to make sure that the stars I needed to align my goto were actually the stars I was looking at. Being unable to find my butt with two hands and a bird dog, I bought a Sky Scout to help me out a bit. In the past month or so I've been using it I can identify with certainty at least a half a dozen stars and a few constellations so, not bad so far.
As a neophyte to astronomy, I needed something to make sure that the stars I needed to align my goto were actually the stars I was looking at. Being unable to find my butt with two hands and a bird dog, I bought a Sky Scout to help me out a bit. In the past month or so I've been using it I can identify with certainty at least a half a dozen stars and a few constellations so, not bad so far. Unfortunately I still can't find my butt.Post a Comment