finderscope

thumb|right|300px|A 50 mm right-angle finderscope mounted on a 150 mm telescope thumb|right|300px|Tour guide points out the double Finderscope on the 24.5 inch Cassegrain reflector|Cassegrain Telescope at the [[Goldendale Observatory State Park.]] A finderscope is an accessory sighting device used in astronomy and stargazing, typically a small auxiliary refracting telescope/monocular mounted parallelly on a larger astronomical telescope along the same line of sight. The finderscope usually has a much smaller magnification than the main telescope, thus providing a larger field of view, useful for manually pointing (a.k.a. "slewing") the main telescope into a roughly correct direction that can easily place a desired astronomical object in view when zooming in. Some finderscopes have sophisticated reticles to more accurately aim the main telescope and/or even perform stadiametric measurements.

==Function and design== Finderscopes contain mechanisms to properly align them with the main telescope's line of sight. Accomplishing this alignment varies based on the design of the finderscope and its mount: usually on amateur telescopes it is done by three or six adjustment screws.