Oh and I wanted to add that I take individual darks for each flat frame. I make master darks using no normalization or rejection and then using the histogram get rid of the pedestal. Then I do the same to the bias frames. Then I load up the individual flats into image calibration, check bias subtraction, check dark subtraction with opimization and then press apply and every now and then it comes up with the correlation error.
It could be because my QHY9 is notorious for straying regulated temperature up to 1 whole degree C? I know there is a parameter in optimization that has to do with temperature and that may be the cause of it. They were set to -40 and some of the images made it up to -39.
Flats and corresponding darks are 7s for L, 17s for R, 15s for G and 32s for B. ( regulation won't really let me get darker so that I can get my L flats over 7 seconds but that should be enough to handle the shutter issue. Plus my Ha darks already have to be 400s!
