March 2011 Sky and Telescope cover
Alnitak Astrosystems’ Pete Kalajian has an article in the March 2011 issue called “Demystifying flat fields” that goes into the (simple) math behind flatting your images and also notes how to characterize the linear range of your camera. Understanding how your camera works is essential to deciding on how choose an exposure length for your flats. Check it out. The digital issue is available online now, and the print issue hits the newsstands February 1.