[Omaroo (Chris Malikoff)]

Thanks Jeanette Yep - I'm reasonable happy with it because I can see that with a bit of experience with it I'll get there.

Cheers Marcus - thanks for the tips

I've been aquiring via CCDSoft5, and taking autodarks automatically, and as you say, the series utilise the same dark frame. I think I'll take them separately from now on so each light uses its corresponding dark frame immediately. I have a library, but not at this temperature. Ambient was far colder than when I built the library, so I have none suitable.

Originally Posted by marc4darkskies

Not bad Chris! What image acquisition and calibration software are you using?

Generally, artifacts in your images can be removed by:

a) dark frame subtraction. It's best to take at least 3 dark frames, median combine, then subract that median dark from your lights. Auto darks (at least in CCDSoft) mean only 1 dark is taken and used for all images in a series.
b) hot/cold pixel removal (eg as in CCDStack) after calibrating, registering and normalising your images
c) you could also dither your images by a few pixels in between light frames so when they're median combined artifacts dissappear or are minimised. 3 subs is the minimum for a median combine but 6 or more is best.
d) Doing all three of the above is even better (that's what I do)

Cheers, Marcus