Gregorian telescope

GNU Webster's 1913

1. adj. (Opt.) a form of reflecting telescope, named from Prof. James Gregory, of Edinburgh, who perfected it in 1663. A small concave mirror in the axis of this telescope, having its focus coincident with that of the large reflector, transmits the light received from the latter back through a hole in its center to the eyepiece placed behind it.
2. n. a form of reflecting telescope. See under Gregorian.

WordNet 3.0

1. n. a reflecting telescope that has a paraboloidal primary mirror and a hyperboloidal secondary mirror; light is brought to a focus through an aperture in the center of the primary mirror