23 July 2008 Manufacture of a combined primary and tertiary mirror for the Large Synoptic Survey Telescope
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Abstract
The Large Synoptic Survey Telescope uses a unique optomechanical design that places the primary and tertiary mirrors on a single glass substrate. The honeycomb sandwich mirror blank was formed in March 2008 by spin-casting. The surface is currently a paraboloid with a 9.9 m focal length matching the primary. The deeper curve of the tertiary mirror will be produced when the surfaces are generated. Both mirrors will be lapped and polished using stressed laps and other tools on an 8.4 m polishing machine. The highly aspheric primary mirror will be measured through a refractive null lens, and a computer-generated hologram will be used to validate the null lens. The tertiary mirror will be measured through a diffractive null corrector, also validated with a separate hologram. The holograms for the two tests provide alignment references that will be used to make the axes of the two surfaces coincide.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
H. M. Martin, J. H. Burge, B. Cuerden, W. B. Davison, J. S. Kingsley, R. D. Lutz, S. M. Miller, M. Tuell, "Manufacture of a combined primary and tertiary mirror for the Large Synoptic Survey Telescope", Proc. SPIE 7018, Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, 70180G (23 July 2008); doi: 10.1117/12.789959; https://doi.org/10.1117/12.789959
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