Finderscope

"slewing") the main telescope into a roughly correct direction that can easily place a desired astronomical object in view when zooming in.

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.

[2] Most finderscopes have one of three viewing orientations: Another type of finder commonly found on amateur telescopes is known as a reflector (reflex) sight.

This non-magnifying sight (technically not a "scope") uses a type of beam splitter to "reflect" a reticle generated by collimating optics into the users field of view.

Since the sight uses a beam splitter "window", instead of an optical telescope with the ability to gather light, objects dimmer than the naked eye limit can not be seen through it.

A 50mm right-angle finderscope mounted on a 150mm telescope .
Tour guide points out the double Finderscope on the 24.5 inch Cassegrain Telescope at the Goldendale Observatory State Park .
Reflex sights such as the Telrad (pictured) are popular alternatives to traditional finderscopes, and are often used in conjunction with them.