Orion 8239 20mm Illuminated Centering Telescope Eyepiece 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 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! Illuminated crosshair precisely centered in eyepiece field of view for accurate results Wide 70-degree apparent field of view makes acquiring and centering target objects a breeze