An optical instrument fitted with a mirror or pair of mirrors set at an angle to the line of sight, for use in viewing objects not directly before…

A contrivance or instrument for finding. A small, low-magnification telescope with a wide field of view attached to a larger telescope for use as…

A short refracting telescope designed for use at night; (also) a pair of binoculars so designed (usually in plural).

A small fixed telescope with cross-wires at its focus, used for adjusting the line of collimation of an astronomical or other instrument.

(see quot.).

A lookdown telescope or microscope (see sense B. 1). Obsolete. rare.

a visual telescope fixed rigidly to a photographic telescope so that the latter may be ‘guided’ manually to follow the course of a star, etc., kept…

An instrument that uses the principle of autocollimation, e.g. to measure parallelism or alignment.

A telescope used to follow the path of a projectile, aircraft, or the like, and mounted so that its elevation and azimuth angles are indicated.

Astronomy. A small, low-magnification telescope with a wide field of view attached to a larger telescope for use as an aid for locating and…

an astronomical telescope designed to operate in orbit around the earth.

A telescope incorporating an image intensifier, allowing use in dark conditions. rare.

a scope (model number AN/PVS-2) for a firearm that acts as a night-vision device, developed in 1964 and used by the U.S. military during the…