A Quartet of interacting galaxies about 70-75 million light years distant with a recession velocity of ~ 1,600 km/sec.
In spite of this a few photons managed to penetrate through my light polluted back yard sky and here is the result. It proved to be one of the hardest challenges I've tried so far. I searched for the "best" sub lengths but this effort was defeated by constantly changing conditions from night to night. In the end I just took all the varying subs, different lengths and all, and let CCDStack combine them.
Luminance = 280 min total at .88 arc-sec through a Astronomik CLS and the TEC180/G2-8300 CCD.
Colour proved more difficult as I'm having issues with blue fringing with the Trius/TEC140/Baader filters. Some of the blue was through the Hutech IDAS and some was through a Baader Semi-Apo. The G & R were unfiltered. I consequently had some bad gradients and in retrospect I should have used the Hutech filter for all colour. And, I wish now I had exposed a lot more blue. With the Baader filter, which gives quite tight blue stars, I probably need 30-40% more time compared to unfiltered. Colour subs ranged from 300, 420, and 480 seconds: R: 116 min G: 116 min B: 130 min
Thanks for looking! Your helpful comments are always instructive and appreciated!
Peter
1400 x 1117
http://www.pbase.com/prejto/image/157705757
2000 x 1596
http://www.pbase.com/prejto/image/157712260
Larger just gets too noisy. I think this is the price I'm paying for imaging in LP and I'm not sure longer/more subs will ever defeat this. Will it???