Has anyone ever see anything like this? A couple of us PI users (addicts) are helping an online acquaintance process some data. His flat frames have never really been quite right, but this is something a bit more severe.
Another strange thing is that his flats don't show the same dust motes and therefore don't get rid of them. This would imply moving dust, but he has a very normal (and automated) setup, I believe. Any thoughts on what might be cause these odd artifacts?
Some flats look fine, BTW, but certain frames and filters have this underlying structure.
Equipment: Planewave CDK 12.5, Apogee U16HC
I'm hoping someone can give us tips on how we might improve his frames and what tests we might be able to run. If you're interested, I could also upload a fair amount of data to the Image Processing Challenge server if you want to try your own hand at it. I can't seem to figure out what the deal is.