Infinity focus and flats

American Association of Variable Star Observers (AAVSO)
Wed, 08/28/2013 - 20:26

I have conflicting advise on whether a proper infinity focus is important to flats for photometry.  I like to make my flats in the evening when it is not posible to run a focus, so the focus is by default where it was for the last image, usually an early AM shot.  Does it matter?


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