XCel ED eyepieces

More Information  · Recommended Accessories Price $67.95 List Price $102.95 Field of view 55° Eye Relief 20mm Focal Length 5mm Number of optical elements 6 Barrel Size 1.25" Weight 8 oz Warranty 2 years Telescope Eyepiece Formula To calculate the magnification and approximate actual field of view of this eyepiece on your telescope, enter the focal length of your telescope below and press the "Calculate" button. mm

In all cases, its long eye relief and low price make it a good choice for eyeglass wearers, particularly those on a budget. Five-layer 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 only be useful with long focal length refractors, reflectors, or catadioptric scopes 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.

A soft rubber eyecup shields the eye from ambient light and rolls down for more comfortable eyeglass use. Two knurled rubber rings on the barrel provides a secure grip when changing eyepieces in cold weather.