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Proceedings Paper

Image Defects From Surface And Alignment Errors In Grazing Incidence Telescopes
Author(s): Timo T. Saha
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Paper Abstract

The rigid body motions and low frequency surface errors of grazing incidence Wolter telescopes are studied. The analysis is based on surface error descriptors proposed by Paul Glenn. In his analysis, the alignment and surface errors are expressed in terms of Legendre-Fourier polynomials. Individual terms in the expression correspond to rigid body motions (deCenter and tilt) and low spatial frequency surface errors of mirrors. With the help of the Legendre-Fourier polynomials and the geometry of grazing incidence telescopes, exact and approximated first order equations are derived in this paper for the components of the ray intercepts at the image plane. These equations are then used to calculate the sensitivities of Wolter type I and II telescopes for the rigid body motions and surface deformations. The rms spot diameters calculated from this theory and OSAC ray tracing code agree very well. This theory also provides a tool to predict how rigid body motions and surface errors of the mirrors compensate each other.

Paper Details

Date Published: 28 July 1989
PDF: 12 pages
Proc. SPIE 1160, X-Ray/EUV Optics for Astronomy and Microscopy, (28 July 1989); doi: 10.1117/12.962663
Show Author Affiliations
Timo T. Saha, NASA/Goddard Space Flight Center (United States)

Published in SPIE Proceedings Vol. 1160:
X-Ray/EUV Optics for Astronomy and Microscopy
Richard B. Hoover, Editor(s)

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