Gregorian telescope

American  

noun

1. a telescope similar in design to the Cassegrainian telescope but less widely used.

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Gregorian telescope British  

noun

1. a form of reflecting astronomical telescope with a concave ellipsoidal secondary mirror and the eyepiece set behind the centre of the parabolic primary mirror

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Etymology

Origin of Gregorian telescope

1755–65; named after James Gregory; see -ian

Example Sentences

In 1774, the music teacher made for himself a five-and-one-half-foot Gregorian telescope; and a year later, a Newtonian, with a four-and-a-half-inch aperture, which magnified two hundred and twenty-two times.

From Famous Men of Science by Bolton, Sarah K.

But in the Gregorian telescope, the image formed by the principal mirror falls on a second mirror, which is very small, slightly curved, and parallel to the first.

From Biographies of Distinguished Scientific Men by Grant, Robert