ASI1600MM Pro dark subratction problem

stubblejumper

When I execute ImageCalibration in Pixinsight, the resulting image is darker in tge areas where the amp glow was present in the master dark. I.E., it is overcompensating and removing signal. The Master Dark is the same configuration as the sub in terms of binning, exposure time and sensor temperature. How is this possible?

wvreeven

I assume the answer is yes, but are the gain and offset also the same?

stubblejumper

I should have included gain and yes the offset too. I never change the offset in processing. Perhaps something has happened that I didn't notice and I will check.

I tried an experiment last night. I captured subs at -10°C and subtracted a master dark which was captured at -20°C. Nothing changed. The theory was that I would be subtracting less noise than was warranted. The problem is in areas with amp glow. In my case on the upper and lower right and upper left.

Don

stubblejumper

I created new master darks and the problem went away. Don't understand why but won't spend any time on it.