1 September 1991 Fabrication of a fast, aspheric beryllium mirror
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A program to fabricate a large, optically fast, aspheric lightweight Be mirror has demonstrated state-of-the-art technology. The mirror blank was fabricated as a 1.0-m diameter, f/0.58 ellipse, directly from IP-70 grade powder, using near-net-shape HIPing as well as a patented tooling approach that produced a closed back, honeycomb-cored mirror weighing less than 18 kg. Details of the mirror design and of the assembly for HIPing are given. The blank was HIPed, leached and machined to final shape with all design goals met; as-HIPed, the blank was within +/- 0.5-mm in all dimensions, and the radius of curvature was within 0.2 percent of target. The mirror was loose-abrasive ground using plunge grinding with a full-size tool, then rough polished using a full-size flexible pitch lap. In-process metrology used a special swing-arm profilometer with demonstrated accuracy and repeatability below one micron.
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Roger A. Paquin, Roger A. Paquin, George J. Gardopee, George J. Gardopee, } "Fabrication of a fast, aspheric beryllium mirror", Proc. SPIE 1485, Reflective and Refractive Optical Materials for Earth and Space Applications, (1 September 1991); doi: 10.1117/12.46520; https://doi.org/10.1117/12.46520

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