Quote:
Originally Posted by Amaranthus
Ray, why would you want/need to temperature match the flats?
Re: Noise, one can also do Gaussian pixel blurring to smooth out flat noise (but still retain sufficient definition of dust motes). I generally take 100 flats per filter/session to minimise noise, which is possible when using a light box.
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Hi Barry. The flats need to be dark subtracted (or at least bias subtracted). in either case, would expect that dark/bias level would vary with the temperature of the camera, so you could be subtracting a different bias from that inherent in the flat. Likely to be minor cf the mismatch of dark and lights, but still possible.
agree that if you do dither, hot pix rejection plus dither stacking gets rid of noise and then you can use smoothed flats to clean up any dust etc without adding more noise.