Title

A unique astigmatic nodal property in misaligned Ritchey-Chretien telescopes with misalignment coma removed

Authors

Authors

T. Schmid; K. P. Thompson;J. P. Rolland

Comments

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Abbreviated Journal Title

Opt. Express

Keywords

OPTICAL-SYSTEMS; ROTATIONAL SYMMETRY; ABERRATIONS; COLLIMATION; Optics

Abstract

We present the aberration field response of Ritchey-Chretien telescopes, with the aperture stop on the primary mirror, to secondary mirror misalignments. More specifically, we derive a general condition for the geometry of the binodal astigmatic aberration field for a telescope that has been aligned to remove field-constant coma. It has been observed that when the coma caused by secondary mirror misalignments is removed the astigmatic field is typically not symmetric around the periphery, but, significantly, it is always effectively zero on-axis. This observation is a manifestation of binodal astigmatism where one of the astigmatic nodes remains near the field center. Here, we show how the condition to remove field-constant coma simultaneously creates a constraint whereby one of the astigmatic nodes must remain effectively on-axis. This result points to why the alignment of a large telescope based on axial imagery is insufficient and demonstrates exactly the geometry of the remaining misalignment aberration field, which dominates the performance of the telescope, providing insights into more complete alignment approaches. (C) 2010 Optical Society of America

Journal Title

Optics Express

Volume

18

Issue/Number

5

Publication Date

1-1-2010

Document Type

Article

Language

English

First Page

5282

Last Page

5288

WOS Identifier

WOS:000275454100032

ISSN

1094-4087

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