Orion 8450 12.5mm Illuminated Reticle Plossl Telescope Eyepiece Four-element 12.5mm focal length 1.25" Plossl telescope eyepiece with an illuminated double crossline reticle Excellent for accurate polar alignment, GoTo system alignment, IntelliScope system alignment, and acquiring and centering of guide stars for guided astrophotography pursuits Fully multi-coated lenses provide bright views with a 40 apparent field of view LED-illuminated double crossline reticle has adjustable focus and brightness Illuminator requires three GP-189 batteries (included)