coudé focus

coudé focus

(koo -day) See coudé telescope.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

coudé focus

[kü′dā ‚fō·kəs]

(optics)

Focus achieved with a coudé telescope.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Coudé Focus

 

a term used to designate the optical system of a telescope in which converging light beams are reflected by one or more plane mirrors such that the focal plane remains fixed for any direction of the telescope's optical axis. Light beams are usually directed to the focal plane through a hollow polar axle. The coude focusing system is used in most large reflecting telescopes, thus making possible stationary mounting of large astronomical spectrographs. For English and German telescope mountings two plane mirrors are required; for American mountings one mirror can be used when observing stars close to the celestial equator, but three must be used for observations far from it.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.