# Dictionary Definition

catoptrics n : branch of optics dealing with
formation of images by mirrors

# Extensive Definition

Catoptrics deals with the phenomena of reflected
light and image-forming optical systems
using mirrors. From the
Greek κατοπτρικός (specular).

The book Catoptrics attributed to Euclid covered the
mathematical theory of mirrors, particularly the images formed by
plane and spherical concave mirrors.

The first practical catoptric telescope (the "Newtonian
reflector") was built by Isaac Newton
as a solution to the problem of chromatic
aberration exhibited in telescopes using lenses as objectives
(dioptric
telescopes).