Orion 8734 17mm Sirius Plossl Telescope Eyepiece This 1.25" 17mm focal length Plossl eyepiece is ideal for all types of telescopes: reflector, refractor, and catadioptric designs including Mak-Cass telescopes and SCTs Perfect for broad-field lunar observations, medium-sized star clusters, and a wide range of cloudy nebulas and deep-sky targets Multi-coated to provide bright views of impressively high contrast Offers a 52 apparent field of view for clear, crisp images of celestial and terrestrial objects Threaded for use with 1.25" Orion filters