Actually, this wouldn't work- what WOULD work is to use a single eyepiece with lenses large enough and focal lengths such that the exit pupil diameter exceeded the size of your interpupilary distance. That should give you a two-eyed view using only one large eyepiece. These little thought exercises tell me that much of the FOV on huge telescopes are wasted when used visually. Oh, well. On Sun, Aug 2, 2009 at 2:30 PM, Chuck Hards <chuck.hards@gmail.com> wrote:
Some large, professional telescopes have image planes with circles of 100% illumination that are the size of a sheet of typing paper- or larger- designed so that a photographic plate in the 8"x10" size could be used. I believe some modern scopes have even larger circles of 100% illumination for specialized detectors and imagers.
What this means is that, say you were sitting in the prime-focus cage of the 200" telescope. You can just hold two identical eyepieces up to your eyes and face the primary mirror for two-eyed views, without any kind of binocular adapter. Or rest them on a piece of glass that occupies the place of the plate-holder, racked in slightly until the eyepieces are in focus. Amazing!