Pentax XO

As we do not charge for a backordered item until it is available to ship, you can order a backordered eyepiece by credit card with no financial penalty if Pentax decides not to go back into production and your order is cancelled. However, do not order by PayPal, as PayPal takes the money out of your account immediately and you will not have use of those funds until Pentax decides whether to go back into production or not and a PayPal refund is issued.

These proprietary eyepieces use either five lenses (in the 5mm) or six lenses (in the 2.5mm) in a three-group design to achieve a sharpness and contrast that is exceptional in high magnification eyepieces. Their chrome barrels are threaded for standard 1.25” filters. A safety groove cut into the chrome barrel engages the thumbscrew of the focuser to keep the eyepiece from falling if the thumbscrew accidentally loosens during use. Both are multicoated on all air/glass surfaces, using proprietary Pentax Super Multi-Coatings (SMC). The edges of the lenses have been blackened to eliminate internal reflections for better contrast. Both use high-refraction, low-dispersion lanthanum (rare earth) lenses to minimize chromatic aberrations and astigmatism. They can be used with all telescope types, and are optically corrected for use with focal ratios as fast as f/4. They have exceptional contrast and excellent center to edge sharpness, with very little ghosting, for critical lunar, planetary, and binary star observing. They are weatherproof to JIS Class 4 standards (which means that dew accumulation won’t cause a problem, although full submersion in a bucket of water is a no-no). Each eyepiece comes with plastic dust caps for the barrel and eye lens and a bolt-type plastic container for storage. They are protected against flaws in materials or workmanship by a lifetime warranty, a rarity in telescope equipment.