1 September 1974 Use Of Screen Rotation In Testing Large Mirrors
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An automated microdensitometer is used to obtain a density distribution on a photographic plate. Each density is proportional to a surface departure from ideal at some point on a mirror during its figuring. The departures are obtained by the screen test method developed at Kitt Peak National Observatory, as applied to the 4-meter primary mirror. It is shown that for various screen rotations with the mirror stationary, easily interpreted results are obtained with this density representation. These results are in good agreement with each other. When all the rotated-screen density representations are made on the same photographic plate, one obtains a composite in which areas of greatest agreement are emphasized and areas of scarce surface sampling are complemented.
© (1974) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
I. Ghozeil, I. Ghozeil, } "Use Of Screen Rotation In Testing Large Mirrors", Proc. SPIE 0044, Instrumentation in Astronomy II, (1 September 1974); doi: 10.1117/12.953949; https://doi.org/10.1117/12.953949


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