Quote:
Originally Posted by jase
Nice work Dennis. As you acknowledge a few things were against you. Things out of your control aside, imaging at F/9.6 will require considerably long sub exposures to bring out the faint spiral structures of the galaxies - even with the high QE of the ST7. If you're operating an ABG then I'd go for 10min subs as a minimum. An NABG would probably be around 5-7min exposures at this focal length (1728mm) before blooming will occur. A 1.07 arcsec/pixel is cutting it fine assuming the conditions are prime. The data looks like it could be stretched a little more. I note the file name indicates you used a sigma clip for the combine function. You may wish to alter the Sigma Factor to ensure you don't discard too many outlier pixels. It actually looks like the value is too high as the background is really smooth, almost mono tone when further brightened using curves. A colour rendition on the cards perhaps? Look forward to seeing more.
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Thanks Jase for the analysis and commentary, which are spot on based upon what I was observing with the ST7 last night. I think I was collecting around 45,000 in the wells at 5 min subs.
This is a definite project for a dark site and as you suggest, with added colour from the CFW8A. I’m rapidly and inexorably approaching the event horizon of multi-session single images, as opposed to my previous approach of going for 10 in one night!
Cheers
Dennis