Solomark 20mm Illuminated Centering Telescope Eyepiece Wide 70-degree apparent field of view makes acquiring and centering target objects a breeze The perfect telescope eyepiece for alignment of computerized GoTo systems or IntelliScope systems with a comfortable 16mm eye relief An invaluable aid to centering guide stars and astrophotography target objects - you'll wish you had one long ago! Relatively low-power 20mm 1.25" telescope eyepiece with an illuminated crosshair reticle with myriad uses is a welcome addition to any astronomer's accessory case Threaded for 1.25" astronomy filters.