Celestron 5mm X-Cel LX Series 1.25" Eyepiece

This Celestron X-Cel LX 5mm eyepiece uses a new six-element fully-multicoated optical system to provide a wide 60° field of view. It gives you good medium to medium high magnification views with short focal length refractors and fast focal ratio/short focal length reflectors. It also provides about the maximum usable magnification for a typical 8" f/10 Schmidt-Cassegrain. Its full multicoatings provide high contrast that makes it a good choice for splitting close binary stars, for seeing faint low contrast lunar and planetary details, and for ferreting out small planetary nebulas.

It generally will 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 with these scopes. 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.

It has a twist-up rubber eyecup and a usable eye relief of 16mm, for virtually unvignetted use with eyeglasses. A no-slip rubber grip ring provides a secure and comfortable grip when handling or changing eyepieces in cold weather. It is parfocal with the other X-Cel LX models so it will require little refocusing when changing between focal lengths.

The Celestron X-Cel LX 5mm comes with dust caps for both ends of the eyepiece and a bolt-type plastic storage case.