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I am pretty sure you can simply apply a flat only. I'll try that once I unpack from my trip and have that computer out. With my CDK flats only often do not get the right result to fully correct vignetting and hot centre areas. A correctly matched temperature and exposure length master dark that is high quality and fairly fresh (not 1 or 2 years old) with a good bias worked really well.Perhaps it depends on your scope but TEC APO's are piece of cake to calibrate as are most refractors.
You can select your master bias for the dark in the dark dialogue box. They are both a subtraction so no difference to the image.
CCDstack has gotten more options over the years, which complication often fights you as with other programs. The main change seems to allow auto selection of darks, biases and flats which I normally select manually so I guess I must be in the minority of users there.
I am not sure how the pixel map is applied. That must be a separate menu box? I wonder if you should apply it first or second. Probably first. Flats are merely correcting the vignetting and dust donuts. Most CCDs seem pretty evenly illuminated. Sometimes a corrector gives an uneven illumination with a definite brighter centre like a reverse donut. Tak BRC250, CDKs, perhaps some reducers do this.
Greg.
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