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4 April 1979 In-Process Measurement Of Fast Aspherics
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Proceedings Volume 0171, Optical Components: Manufacture and Evaluation; (1979)
Event: Los Angeles Technical Symposium, 1979, Los Angeles, United States
In the fabrication of fast aspheric mirrors having diameters in the 20-30 inch range, it ceases to be practical to introduce the required correction by polishing alone. One is faced, therefore, with aspheric figure control of a surface which cannot be tested optically. To overcome this problem we have adopted the use of precision profile monitors which can provide a prepolishing surface having an accuracy of better than one micron. Upon reaching the polished stage we have found that a wire tester provides the most convenient means for figure control. However, for the final stages of polishing, where local hand correction may be required, it is desirable that the wire tester be replaced by a full aperture interferometric technique; usually a null lens. Described in this paper is a three stage monitoring procedure which uses a profile monitor, a wire tester and a null lens. Accuracy and convenience of each technique are discussed. Also, suggestions are made concerning the optimum point at which one instrument should be exchanged for another.
© (1979) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John Bender and Graham Flint "In-Process Measurement Of Fast Aspherics", Proc. SPIE 0171, Optical Components: Manufacture and Evaluation, (4 April 1979);

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