Newtonian-Cassegrain telescope

Newtonian-Cassegrain telescope

[nü′tō·nē·ən ′kas‚gran ′tel·ə‚skōp]
(optics)
A modification of a Cassegrain telescope in which the light reflected from the hyperboloidal secondary mirror is again reflected from a diagonal plane mirror and focused at a point on the side of the telescope, avoiding the need to pierce the primary mirror and making the eyepiece more accessible. Also known as Cassegrain-Newtonian telescope.