A high-performance 16.5mm 2″ eyepiece for use with high-grade telescopes

The PENTAX XW-16.5 is a premium eyepiece that has an 85° apparent angle of view, 20mm eye relief, and splashproof body. It will provide exquisite views of large deep-sky objects.

High-Grade Optics for Exceptional Image Quality

The high-performance XW-series optics incorporates high-refraction, extra-low-dispersion lanthanum glass elements to produce a well-balanced image with minimal aberrations. It is particularly designed to reduce the disturbing blackout effect by effectively compensating the spherical aberration of the pupil.

PENTAX-Original Multi-Layer Coating for Outstanding Light Transmission Efficiency

All lens surfaces that come in contact with air are treated with the original multi-layer coating, while all laminated surfaces are treated with the innovative partial coating, to offer the light transmission efficiency of more than 90 percent (an astonishing 96 percent at 550nm) over the visible light spectrum.

Advanced Light-Shielding Technology for Improved Image Contrast

Thanks to PENTAX’s advanced computer simulation technology, the XW series features a light-shielding diaphragm at the most effective position to drastically reduce internal reflections for a brighter, higher-contrast image.

Comprehensive Lineup to Accommodate All Applications

Featuring functional, practical focal lengths, the XW eyepiece series provides a comprehensive lineup that accommodates all types of applications, from low-magnification viewing of stars to high-magnification observation of planets.

Weatherproof Construction for All-Weather Viewing

The XW series features JIS Class 4 weatherproof construction,* making it possible to use it in drizzle or under night dew.

* The XW-series eyepieces are not designed for underwater use and should not be submerged under water.

Sleeve Size and Eyecup Design

Members of the XW series come in two diameters: 1.25″ or 2″. When you remove the screw-on eyecup, it also provides a screw thread with a 43mm diameter and a 0.75 pitch. The XW-16.5 has a 2″ sleeve.