1 December 1975 Fabrication and Test of 1.8- Meter-Diameter High Quality ULE Mirror
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The purpose of this investigation was to determine the feasi-bility of producing large diameter, high quality optical surfaces similar to those that will be required for some of the planned orbital observing units such as the Large Space Telescope (LST). Current requirements for the Large Space Tele-scope require that a A /20 rms wavefront be produced at the Cassegrain focus. A reasonable distribution of error sources would, therefore, demand that the primary mirror be figured to a tolerance of A/64 rms on the surface. NASA has funded the initial step toward demonstrating the ability to meet that requirement. An optical fabrication demonstration program was undertaken using an available 1.8-meter-diameter ULE monolithic mirror blank weighing on the order of 1,200 pounds. The mirror that was used had no central perforation and was approximately 12 inches thick with 1-inch front-and hack-plates. In order to accomplish this task, a variety of support and test equipment was designed and fabricated and the actual optical fabrication and test were conducted over a period of approximately eight months. The results of this effort yielded a mirror with a surface quality of 0.015 wave rms or A/65.3. = 632.8 nanometers.)
Richard J. Wollensak, Clarence A. Rose, "Fabrication and Test of 1.8- Meter-Diameter High Quality ULE Mirror," Optical Engineering 14(6), 146539 (1 December 1975). https://doi.org/10.1117/12.7971790 . Submission:


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