- a telescope similar in design to the Cassegrainian telescope but less widely used.
Origin of Gregorian telescope
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- a form of reflecting astronomical telescope with a concave ellipsoidal secondary mirror and the eyepiece set behind the centre of the parabolic primary mirror
C18: named after J. Gregory (died 1675), Scottish mathematician who invented it