Surface distortions of a 3.5-meter mirror subjected to thermal variations

Myung K. Cho; Gary A. Poczulp

doi:10.1117/12.48261

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1 December 1991 Surface distortions of a 3.5-meter mirror subjected to thermal variations

Myung K. Cho, Gary A. Poczulp

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Proceedings Volume 1532, Analysis of Optical Structures; (1991) https://doi.org/10.1117/12.48261
Event: San Diego, '91, 1991, San Diego, CA, United States

Abstract

Finite element analyses were performed to predict the optical surface distortions for a 3.5-meter borosilicate glass structured mirror due to the effects of thermal variations. In order to evaluate the performance of the mathematical mirror model, a parallel experimental study was conducted at the National Optical Astronomy Observatories (NOAO). A total of 666 thermal sensors was bonded to the mirror for the experiment. Temperature distributions measured by the thermal sensors were directly translated by an interface program into a set of the nodal temperatures for input for the numerical model, and the optical surface distortions were calculated. Excellent agreement between the experimental and numerical results were found. Additionally, an analytical approach for a linear thermal gradient along the optical axis was made, and the result agreed closely with that from the finite element analysis.

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Myung K. Cho and Gary A. Poczulp "Surface distortions of a 3.5-meter mirror subjected to thermal variations", Proc. SPIE 1532, Analysis of Optical Structures, (1 December 1991); https://doi.org/10.1117/12.48261

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