Newtonian telescope
noun
a reflecting telescope in which a mirror or reflecting prism is mounted on the axis near the eyepiece so that the image may be viewed from outside the telescope tube at right angles to the axis.
Origin of Newtonian telescope
First recorded in 1755–65
British Dictionary definitions for newtonian telescope
Newtonian telescope
noun
a type of astronomical reflecting telescope in which light is reflected from a large concave mirror, onto a plane mirror, and through a hole in the side of the body of the telescope to form an image