Astro-Tech 1.25” Long Eye Relief eyepieces provide exactly what their name implies, a long and comfortable 20mm eye relief that makes for very comfortable high power lunar and planetary observing. They are particularly useful if you must
wear eyeglasses due to moderate to severe astigmatism, as they let you wear your glasses and still see the entire field of view. For those who don’t wear glasses, your eyelashes won’t brush annoyingly against the Astro-Tech eyepiece lenses when you observe as it often does with short eye relief eyepieces, where they can leave streaks of eyelash oils that have to be cleaned off regularly.
In addition to the comfortable eye relief, the Astro-Tech Long Eye Relief eyepieces have an advanced proprietary seven lens optical system that provides a very flat field to keep stars and planets in sharp focus from one edge of the 55° eyepiece field to the other. There is no need to constantly refocus to keep the image sharp as an object drifts across the field, a virtue that Dobsonian owners will particularly appreciate (but a visual virtue all telescope owners will enjoy).
All Astro-Tech Long Eye Relief high power eyepieces are parfocal, to minimize the need for refocusing when you change eyepieces. The edges of their lenses are blackened and the interiors of the barrels finished in matte black with antireflection threading. The resulting low internal reflections give you high visual contrast on subtle lunar and planetary detail, with a dark sky background that makes low surface brightness deep space objects stand out more clearly. All lenses are fully multicoated with the latest broadband high transmission/antireflection coatings for excellent light transmission and low ghosting.
Each Astro-Tech Long Eye Relief eyepiece has a roll-down rubber eyecup for eyeglass use. Eyeglass wearers typically roll the eyecup down to provide a cushion to keep their eyeglasses from getting scratched should they accidentally bump the eyepiece when observing. Those who don’t wear glasses can roll them up to help shield their eye from ambient light to improve the image contrast.
The focal length of each Astro-Tech Long Eye Relief eyepiece is laser-etched into the eyepiece body to provide permanent visibility. A rubber grip ring that runs the full length of each eyepiece barrel provides a sure grip when wearing gloves or mittens in cold weather. Protective dust covers are provided for both ends of each eyepiece.
A slanted safety groove is machined into each 1.25” barrel. This engages the thumbscrew or compression ring of your star diagonal or focuser drawtube to keep the eyepiece from falling should the thumbscrew accidentally loosen during use. In addition, the barrel is threaded to accept standard 1.25” color and light pollution filters. In addition, the Astro-Tech Long Eye Relief eyepieces are protected by a two-year warranty, twice that of competitive eyepieces (even those costing nearly twice as much).