I'm a latecomer to publishing the Horsehead Nebula this season. I did this over New Year's Eve and New Year's nights (dodging clouds), so it's "years" in the making...
HA only, 10 min subs at -10C. This image uses 21 subs (3.5 hrs), although I had another 4 more subs that I could not get registered.
I used 15 darks, no flats. The darks I did on New Year's night during the cloudy sessions. The image has barely been cropped, just to get rid of the integration artifacts at the edges.
The noise in this image was terrible and you won't have to look hard at finding some. The black spots that are everywhere, but most prevalent in the top left, are awful. Any ideas on fixing in the processing?
Assuming I go back and redo the processing I will probably try to clean up the stars a bit more. I think I read something about that somewhere - will have to hunt for the details again. So any tips here also appreciated.
Old version:
New Version:
A larger version of the new version can be seen here:
https://flic.kr/p/CbJPMv
Side note: Guiding for these images was interesting. I was using PHD2 and it picked up a very bright star, so much so that my normal 1 sec exposures were blowing it right out and not giving very good guiding results. So I went to 0.2, 0.1 and 0.05 sec guiding (at different times, wondering how low I could go). This was amazing. The bullseye target became very tight, with almost everything in the inner 1" ring (which you'd hope with such a short exposure time). In turn the mount adjustments were a lot smaller too, although, of course, quite frequent.
