Coating the 8-m Gemini telescopes with protected silver

Maxime Boccas; Tomislav Vucina; Claudio Araya; Esteban Vera; Clayton Ahhee

doi:10.1117/12.548809

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24 September 2004 Coating the 8-m Gemini telescopes with protected silver

Maxime Boccas, Tomislav Vucina, Claudio Araya, Esteban Vera, Clayton Ahhee

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Proceedings Volume 5494, Optical Fabrication, Metrology, and Material Advancements for Telescopes; (2004) https://doi.org/10.1117/12.548809
Event: SPIE Astronomical Telescopes + Instrumentation, 2004, Glasgow, United Kingdom

Abstract

The Gemini telescopes were designed to be infrared-optimized. Among the features specified for optimal performance is the use of silver-based coatings on the mirrors. The feasibility study contracted by Gemini in 1994-1995 provided both techniques and recipes to apply these high-reflectivity and low-emissivity films. All this effort is now being implemented in our coating plants. At the time of the study, sputtering experiments showed that a reflectivity of 99.1% at 10μm was achievable. We have now produced bare and protected silver sputtered films in our coating plants and conducted environmental testing, both accelerated and in real-life conditions, to assess the durability. We have also already applied, for the first time ever, protected-silver coatings on the main optical elements (M1, M2 and M3) of an 8-m telescope. We report here the progress to date, the performance of the films, and our long-term plans for mirror coatings and maintenance.

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Maxime Boccas, Tomislav Vucina, Claudio Araya, Esteban Vera, and Clayton Ahhee "Coating the 8-m Gemini telescopes with protected silver", Proc. SPIE 5494, Optical Fabrication, Metrology, and Material Advancements for Telescopes, (24 September 2004); https://doi.org/10.1117/12.548809

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