About the Baader 21mm Hyperion Modular Eyepiece - 1.25"/ 2"... The Baader Planetarium Hyperion 68 Degree Modular Eyepieces offer world-class performance and unique photo-visual features at an unheard of price. No longer do amateurs need to spend more on their eyepieces than their primary instrument in order to get true high-end performance in a wide-field eyepiece. Not just a different branded version of their highly regarded cousins, the Hyperions have been totally redesigned to deliver better transmission, contrast, and useful new features. Baader Planetarium has worked hard to give the Hyperions the world''s finest optical coatings, superb mechanics, and their unique multi-functional design. As a visual eyepiece, we have found the Baader Hyperion Modular Eyepieces deliver superb sharpness and color fidelity across their 68 degree wide, flat-field, even in fast telescopes. From their superb on-axis and off-axis sharpness, to their pitch-black high contrast field, the Hyperions really work. Viewing through a Hyperion is notably comfortable and relaxing, due to their forgiving eye-position, 20mm of eye-relief, and an optical design that is free of the annoying kidney-bean effect. Baader 21mm Hyperion Modular Eyepiece - 1.25"/ 2" Features... Consisting of 8 elements in 5 groups, the Hyperion optical design delivers outstanding sharpness and color correction over a true 68 degree wide field, along with a comfortable 20mm of eye-relief. High grade water-white glasses are used throughout, to deliver a crystal clear view with low scatter and excellent color fidelity, free of the yellow or bluish coloration imparted by many other eyepieces. Use of high-index glasses delivers low distortion and astigmatism, even on scopes as fast as f/4. Baader Planetarium has gone to great lengths to give the Hyperions the most advanced multicoatings ever used on amateur telescope eyepieces (please note: these are not the same coatings other manufacturers use on their similar clones of these eyepieces..). The Hyperion multi-coatings and coating equipment are proprietary to Baader and have been designed by German coating engineers specifically for the Baader Hyperions, and optimized for each of the glasses used. These coatings are applied with the latest thin-film German coating equipment, training, and process controls. The result are coatings that truly rival the best in the world - including the famous Zeiss Abbe Orthoscopic! The difference is clearly visible - users report that the Hyperions clearly show fainter stars and darker sky than the competitive clones. The proprietary Hyperion housings have been engineered by Baader to incorporate careful opto-mechanical design and execution of internal baffling to eliminate stray light and ghost reflections. Uncapping the eyelens reveals a pitch black interior, with no distracting and contrast-robbing glints of light from unbaffled lens or metal surfaces. We call these our ''black hole'' eyepieces. Superb fit and finish. Eyepiece barrels are accurate to size, nicely machined, and hard-anodized. Works in both 1.25" and 2" focusers. The 1.25" barrel is threaded for filters and kept short (0.94") to work well in binoviewers and spotting scopes. Baader''s new housing incorporates a full-length 2" barrel (0.94" long) and provides a specially designed tapered locking recess. In addition, the Hyperion field stop locations have been re-designed and optimized to give the shortest focus position possible (important for binoviewer use). Soft folding rubber eyecups work for both normal and eyeglass users. Each Hyperion comes with protective lens caps and leatherette storage pouch. Accepts popular Astigmatism Correcting Lenses. The Hyperion eyelens housing is compatible with the full range of correcting lenses from .25 to 3.5 Diopters. Observers with any astigmatism will really appreciate this feature, no longer needing to wear eyeglasses to see stars as true pinpoints. The long 20mm eye relief of the Hyperions works particularly well with these corrector lenses, without forcing the observer to press their eye close to the lens in order to see the entire wide field. Great for Binoviewing! We''ve tried most of the wide field eyepieces on the market that are suitable for binoviewing, and the Hyperions are at the top with the very best. When compared to some wide field eyepieces developed especially for binoviewing, we found the Hyperions were superior in every aspect: more comfortable view with better eye relief, smaller housing diameter at the eyelens gives more nose-room, better coatings (=better contrast), wider field, and half the cost. The Baader Hyperions incorporate some unique and innovative aspects, which are designed to make them the ideal projection eyepiece. The optical design of the Hyperions enables them to work as an extremely sharp wide-field projection eyepiece for even large chip CCD and DSLRs. The eyelens barrel has been provided with two different external threads, M43 and M54 (these are covered by the removable rubber eyecups). A complete system of adapter rings enables cameras to be directly (and rigidly) close-coupled for afocal projection, or variably extended for classical eyepiece projection imaging with our T-Adapter and Extension Tubes. A series of 16 threaded rings provides compatibility with just about every digital (CCD/DSLR) and videocamera made, even large and heavy 3-chip videocameras. The front negative lens element is designed to be removed (and exposes an M48 2" filter thread). This converts each Hyperion into a longer focal length high-quality projection eyepiece, giving the imager two choices of focal length with each eyepiece. Baader 21mm Hyperion Modular Eyepiece - 1.25"/ 2" Specifications... Optical Design: Hyperion Modular Barrel Size: 1.25"/2" Eyepiece Field of View - Apparent: 68 degrees Eyepiece Focal Length: 21mm Eyepiece Eye Relief: 20mm Eyepiece Manufacturer Series: Baader Hyperion Eyepiece Weight: 13.7 oz. Field Stop: n/a Number of Lens Elements & Groups: 8 elements, 5 groups Baader Planetarium Product Number: HYP-21
