Infinity focus and flats

Affiliation
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?

 

This post has been locked because it is a double post.  Please visit http://www.aavso.org/infinity-focus-and-flats-0 for discussion.