27 July 2016 The Gemini Observatory protected silver coating: ten years in operation
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Since 2004 the Gemini telescopes have used a protected 4-layer silver coating on their 8-meter diameter primary mirror and other smaller optics. Protected silver was chosen for the twin telescopes due to its high reflectivity and low emissivity properties. For over 10 years the protected 4-layer silver coating at Gemini exceeded the science requirements for reflectivity of 88% between 0.4-0.7 μm and 84% between 0.7-1.1 μm. Initial durability requirements that the coating should last at least two years have been also been surpassed. All mirrors have met the durability requirement, with most outlasting it significantly. Provided is a ten year retrospective on the progress in the use and maintenance of 4-layer silver coatings on large astronomical optics.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
T. Schneider, T. Schneider, T. Vucina, T. Vucina, C. Ah Hee, C. Ah Hee, C. Araya, C. Araya, C. Moreno, C. Moreno, "The Gemini Observatory protected silver coating: ten years in operation", Proc. SPIE 9906, Ground-based and Airborne Telescopes VI, 990632 (27 July 2016); doi: 10.1117/12.2233756; https://doi.org/10.1117/12.2233756


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LSST reflective coating studies
Proceedings of SPIE (July 05 2006)
Mirror cleaning investigations at the CFHT
Proceedings of SPIE (May 31 1994)
Gemini primary mirror in situ wash
Proceedings of SPIE (July 09 2008)

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