An astronomical instrument consisting of a telescope turning about the centre of a graduated arc. See dip-sector n., zenith sector n.

a telescope designed for astronomical use, typically a reflecting or refracting telescope giving an inverted image.

A telescope used for ‘sweeping’ the sky: cf. sweep, n. 7, sweep, v. 21 ? Obsolete.

a telescope of comparatively low power and large field of view, used in searching for comets.

a telescope incorporating a camera.

An astronomical telescope or camera employing a concave primary mirror, a convex secondary mirror, and a Schmidt corrector plate, so as to…

(originally) a telescope in space; (now) spec. an astronomical telescope that operates by remote control in earth orbit to avoid interference from…

Astronomy. A telescopic apparatus for measuring the polarization of light from celestial objects; a polarimeter combined with a photometer.