The Tele Vue 17.3mm Delos eyepiece designed for medium power/high contrast solar system and deep space observing with all telescope types and sizes. It has a long 20mm eye relief that makes it ideal for eyeglass wearers. It is designed to use the Tele Vue Dioptrx astigmatism-correcting lenses, so you can even observe without your glasses, should you so desire.
There is an adjustable height eyeguard with a soft rolldown eyecup to shield the eye from ambient light and improve the image contrast. The eyeguard height can be locked in place at any point desired.
The 17.3mm Delos has all the virtues like high contrast, a neutral color balance and full field sharpness. Astigmatism is well-controlled, as is field curvature, lateral color and angular magnification distortion correction. In addition, the Delos has low pupil sensitivity (kidney bean effect) for daytime use.
The 17.3mm Delos has a 1.25" barrel that is threaded for standard 1.25" eyepiece filters. A safety groove is machined into the chrome barrel to engage your focuser thumbscrew. This will help prevent the eyepiece from falling should the thumbscrew accidentally loosen while observing. The main eyepiece barrel is narrow enough to comfortably use a pair of 17.3mm Delos in a binoviewer. Rubber grip rings provide a sure grip in cold weather when wearing gloves or mittens. Dust covers are provided for both ends of the eyepiece.