Baader 31mm Hyperion Aspheric 2" EyepieceNormally, near the edge, rays are refracted towards the center when passing a lens, as near axis light beams. Therefore, the image field in an uncorrected system can become blurred to the edge. The aspherical correction of an optical system, as with these eyepieces, now resolves numerous imaging errors at once. The sharpness is achieved over the entire image field, the distortion is reduced to a minimum and the eyepiece can be made much smaller and