Product Overview

The Pentax XW40-R eyepiece is built for long, relaxed sessions under the stars. With a 40mm focal length, 70° apparent field and a generous 20mm of eye relief, it gives you big, sweeping views of objects like the Pleiades, Andromeda and rich Milky Way star fields while still being comfortable for glasses wearers. The 2" barrel drops straight into modern focusers, and the twist-up rubber eyecup makes it easy to find and hold the sweet spot, even in the dark.

Optically, this is classic Pentax XW gear: six-element, five-group lanthanum glass, fully multi-coated surfaces and smart internal baffling to keep contrast high and stray light out. Light transmission tops 90% (around 96% at 550nm), so faint nebulae and galaxies stand out cleanly against a dark background. The JIS Class 4 weather-resistant body shrugs off dew and drizzle, and the grippy, slip-resistant housing feels solid and secure in the hand. If you want a premium wide-field eyepiece that just works every time you head out bush or into the backyard, the XW40-R is a rock-solid choice.

Key Features

• 40mm focal length with 70° apparent field of view lets you frame expansive nebulae, star clusters and galaxies in a single, immersive view.
• Generous 20mm eye relief and twist-up rubber eyecup provide comfortable viewing for extended sessions, including for observers who wear glasses.
• High-refraction, extra-low-dispersion lanthanum glass elements minimise aberrations, delivering sharp, high-resolution images across the field.
• Fully multi-coated optics with Pentax SMC coatings achieve over 90% light transmission (up to 96% at 550nm), improving brightness and contrast in low-light conditions.
• Advanced internal light-shielding design reduces stray reflections and blackout, enhancing image contrast and making faint deep-sky objects easier to detect.
• Weatherproof JIS Class 4 construction resists drizzle and night dew, so the eyepiece can be used confidently in typical outdoor observing conditions.
• 2" (50.8mm) barrel diameter is compatible with standard large-format telescope focusers, maximising field stop size and true field of view.
• Slip-resistant textured body and robust build offer secure handling and durability when swapping eyepieces in the dark or cold.
• Helicoid-style eyepiece ring and adjustable light shield help you position your eye optimally, improving comfort and maintaining maximum contrast.
• Supplied caps and case protect the optics during storage and transport, helping maintain performance over years of use.