Thought I'd do some flat frame testing this afternoon, concerned about the dust evident in shots I've done..... initially put down to dust on the CCD, which always looked spotless to me....
So I shot some flats through the UV filter, and also straight to the CCD too.....
Pretty clear where the dust is now!!!
Both are stacks of 5 0.02s shots at the blue sky, identical levels applied in CS2....