The Celestron Ultima LX Series of wide angle eyepieces use six to eight lenses to combine a wide 70° apparent field of view with an eyeglass-friendly 16mm of eye relief. Each is fully multicoated and computer-optimized for excellent correction of chromatic and spherical aberration and astigmatism. The lens edges are blackened for high contrast. They all have a large 28mm clear aperture eye lens for comfortable observing. They are parfocal, to minimize the amount of refocusing needed when switching between eyepieces within the Ultima LX series. They may not be parfocal with other eyepieces in your collection, however.
Each eyepiece has a twist-up rubber eyecup to shield your eye from ambient light. The 5mm, 8mm, 13mm, and 17mm focal lengths have dual concentric barrels that let you use them in both 1.25” and 2” star diagonals and focusers. The barrels of these four focal lengths are threaded for standard 1.25” color and light pollution filters. The 22mm and 32mm versions fit 2” star diagonals and focusers only. The barrels of these focal lengths are threaded for 2” filters.
All have a rubber covering that is scratch and dent resistant. Their no-slip grip design assures secure handling, even when covered with dew. Their “roll-guard” ergonomic design prevents the eyepiece from rolling off a flat surface, such as an observing table. Supplied plastic caps seal both ends of the eyepiece to keep it dust free. A groove machined into the chrome barrel of the eyepiece acts as a safety stop to keep the eyepiece secure should the focuser thumbscrew loosen slightly while using the eyepiece.
The eyepieces work well for low to high power observing with all telescope types and focal ratios. They have very good color correction, with virtually no field curvature, astigmatism, or ghosting. The wide 70° field of the Celestron Ultima LX eyepieces make them a good choice for observing large scale objects – open star clusters, the larger nebulas, etc.