When constructing my possible targets for astrophotography, apparent size is an important criterion. It would be enormously beneficial if one could search for objects by apparent size. For example, for a given telescope and camera setup, the Andromeda Galaxy, with it's apparent size of 177.8 x 69.7 arcmin, is too big to image. On the other hand, the Horsehead Nebula, with it's apparent size of 6 x 4 arcmin, is too small. It is quite tedious going through the entire list of "Tonight's Best" and reviewing all the apparent sizes to finally figure out what I can image.
Search Tonight's Best (or search anything) by Apparent Size