I’ve recently started shooting some hydrogen alpha with my QSI 683. I’ve just recently reached 10 minutes as the maximum for unguided exposures, so I started by guiding so I could go 15 minutes, which at f/3 (Veloce RH-200 optic) got me some pretty decent results for my first couple of tries. The stars in the full sized image though were a little out of round for my tastes. Probably due to a combination of the short guide scope, big pixels on the guide camera, and the various settings one needs to know to get the most out of most guiding packages. This was actually my very first attempt at guiding (well, first attempt at actually getting an image), as I’ve challenged myself by extending my unguided record progressively.
The other night I decided to do some more Ha, but I thought I’d try unguided and extend beyond 10 minutes. The weather was not so good, and the seeing softer, but the stars were indeed more round. I got better results 15 minutes unguided than I did with my previous guided attempt. Now, granted this was with a 600mm focal length scope, and I was binning 2×2 so the scale was 3.75 arc seconds per pixel. This is still no small feat, and is the result of a few years practice, and of course the Software Bisque “ecosystem”.
This is a huge leap forward for me personally as an imager, but it’s also a tribute to the current “State of the Art” in amateur imaging. My toolset and routine has progressed to the point where I can do the following:
- Set up a field tripod and get it nearly perfectly level in just a few minutes.
- Do a rough polar alignment during the day using the sun, moon, or bright planet.
- Because I was level when I did step #2, 10 to 15 minutes after sunset, I can get a star on camera, do my sync and start a first short T-Point run. Uhg, turn two and a half complete turns… wow I was way off… This is still okay.
- Run a more lengthy automated run with 50 or so points to refine polar alignment to within two or three arc minutes at worst from the pole.
- By the time astronomical twilight has come and my scope has cooled sufficiently for imaging, I’ve done a 250 point T-point run (binned for speed), and run Super Model.
- Turn on ProTrack. Shoot 15 minute subs for three hours. No guiding. In fact, I’m starting to believe ProTrack is better than guiding. There was just the tiniest black seam around two edges from the stack/alignment. I think I could have went 20 minutes to tell the truth. I can hardly wait for better weather to continue this exploration.
So, I’m very excited by my current progression, and I’m really liking narrow band imaging. I especially like that I can image from home in light polluted skies, and you can be sure the oxygen and sulfur narrow band filters are on my wish list for further exploration.
In the mean time, my next few blogs will be about the details about the “Six step” system I listed above. Even if your not entirely in the Software Bisque ecosystem, you might still find some of my school or hard knocks learned lessons valuable.
07-28-2012 11:35 PM