Abstract

Several modifications of the Cassegrainian-type telescopic system using a spherical secondary mirror are discussed in terms of the effect of such modifications on the image quality at moderate apertures and focal lengths. Both third-order and trigonometric methods are used to compare the various systems. It is found that an f/11 true Cassegrainian system of EFL 130 inches gives excellent image rendition over a field of approximately 1.7 degrees, while a more easily manufactured modified system of the same optical dimensions using a spherical secondary mirror and an ellipsoidal primary mirror gives equivalent image rendition over a field of approximately 0.42 degree.

© 1953 Optical Society of America

Application of the Rayleigh Criterion to the Null Test of Dall-Kirkham Primary Mirrors

P. R. Yoder, F. B. Patrick, and A. E. Gee
J. Opt. Soc. Am. 45(10) 881-883 (1955)

Anastigmatic catadioptric telescopes

Robert J. Lurie
J. Opt. Soc. Am. 65(3) 261-266 (1975)

Coma of Modified Gregorian and Cassegrainian Mirror Systems

Robert T. Jones
J. Opt. Soc. Am. 44(8) 630-633 (1954)

Optical System for Large Telescopes

Seymour Rosin
J. Opt. Soc. Am. 51(3) 331-335 (1961)

Cassegrainian/Gregorian-type null correctors for surface measurements of radio telescope reflectors

A. Greve
Appl. Opt. 36(22) 5283-5287 (1997)