Spend less time centering your target and more time stargazing with Celestron 's StarPointer Pro . It was designed to provide the easiest experience locating celestial objects in the night sky by projecting a dual circle reticle to allow you to find your object without obstructing it. The circles also serve as a measuring tool while starhopping. For added convenience, StarPointer Pro features a 40 mm optical window with a large field of view. The StarPointer Pro has a rheostat to control the reticle brightness and attaches quickly to most telescopes with a dovetail connection and finger knobs.