Exactly, Erik echos my feelings on the subject. So, if your pupil is too small to accomodate a particular eyepiece/objective combination, you waste a bit of aperture. If you are after a wider FOV, it's one of the tradoffs you make, no big deal. I'm not going to pack a special reduced-aperture telescope along just for very low power, nor am I going to not use a particular eyepiece on a larger scope because I won't be able to use the entire objective. It's only at the very low power end that this comes up, one end of the "bell curve" of the full range of employed magnification. A non-issue, mostly just one of those abstract bits of info that's fun or interesting to mull over. On 7/21/10, erikhansen@thebluezone.net <erikhansen@thebluezone.net> wrote:
Also, while I think it is a good idea to determine exit pupil of your eyepieces, I would not let it keep you from buying an eyepiece that yields a bigger field of view. For, instance I had and eyepiece that yielded a 10mm exit pupil, but it gave a 4 degree field of view. Views of the entire Veil Nebula and N. American are spectacular despite the exit pupil that is incompatible with the human eye.