Quote:
Originally Posted by Somnium
SO i have read both that you need to take bias images and you don't need to take bias images . given that you are going to take darks, some suggest that the dark images already have the bias data included ... but, isn't the bias data also included in the flat field images ? so when you process the subs, you are subtracting the bias with the darks then adding it in again with the flats therefore you would need a bias only image to subtract it again. with that rabbit hole opened, wouldn't you need to take your flats at the same sensor temp as your subs, darks and Bias'
thoughts ?
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A bias is a zero second dark exposure, so by definition all darks already have bias information.
Bias is only useful if you want to scale dark frames. If you use an SBIG camera I'd advise against this, as the dark noise is non-linear. You'll get cleaner data by using equivalent time/temperature darks.
Flats should be dark calibrated, hence have both dark and bias removed from them.