Please note: This text was taken directly from the manufacturer.
With their 66-deg apparent field of view, our Expanse wide-field eyepieces will definitely turn up the Wow! factor in your deep-sky observing experiences! Imagine taking in objects like the Andromeda Galaxy, the Double Cluster, or the star clouds in Sagittarius in one sweep! With an Expanse in your focuser, you can! Expanse oculars have big eye lenses and great eye relief (13mm to 17mm). Eyeglass wearers can view the entire field without removing their glasses. All eyepiece elements are fully coated, with the outer lens multi-coated for additional light transmission. Each 1.25" aluminum barrel is threaded for filters and internally blackened to eliminate internal scattering. And their fold-down rubber eyeguards enhance contrast by blocking stray light. With our Expanse eyepieces you get a super wide field of view and superior optical performance. And check out the price. You also get a bargain!
