So I started this yesterday and lost the message before posting so here we go again....I've loaded a set of files on my Dropbox account that has one raw light, a set of three flats taken at different times which all appear the same. My target ADU for these is 25,000 ADU. I use a SBIG STL-11000M camera and image at -20. A master dark is used as well as the flat. Due to my imaging train having a rotator I have both east/west flats. What I noticed if using the flats leaves the doughnuts very well pronounced while just using a dark to calibrate seems to tame them considerably. I use an Optec FlatMan XL flat panel and minimum exposure for all flats is 1 second. The images post in the link contain the three different flats, a single raw light that has been
processed using only the dark, one with both dark and flat (one done using east flat the other using a west flat). Seems I'm missing something. I thought that I had a bad set of flats so I took a new set on two different occasions with the same result. Any idea where I'm messing up? I've been processing images for years and this stumps me. You can see increased vingyetting with the frames using the master flats vs just the master dark.
https://www.dropbox.com/sh/28b6m4qot889zei/AAAtiACj9JNSATeM7v7MKZnxa?dl=0
