| This short focal length TeleVue Radian eyepiece is outstanding for medium to medium high magnification viewing with short focal length refractors and fast focal ratio/short focal length reflectors. It also provides about the maximum usable magnification attainable with a typical 8” f/10 Schmidt-Cassegrain. Its high contrast makes it an exceptional choice for splitting close binary stars, for seeing faint low contrast lunar and planetary details, and for ferreting out small planetary nebulas. It will generally be useful with long focal length refractors, reflectors, or catadioptric scopes only under very good or better seeing conditions. Average seeing conditions would limit its usefulness. Using it with a 2000mm 8” f/10 Schmidt-Cassegrain, for example, will result in 400x (50x per inch of aperture) and a 0.5mm exit pupil (about 1/50th of an inch across). Both of these are right at the rule of thumb maximum values of magnification per inch of aperture and exit pupil size for usable observing under good to very good seeing conditions for a reasonably experienced observer. |
Email page link to a friend
