Coating and cleaning of the Subaru Telescope mirrors

Takeshi Noguchi; Tomio Kanzawa; Tomio Kurakami; Saeko S. Hayashi; Masami Yutani; Norio Oshima; Masao Nakagiri; Kiichi Okita; Katsumi Imi; Robert Potter; Goro Sasaki; Yukiko Kamata; Tsuyoshi Ishikawa

doi:10.1117/12.391529

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20 July 2000 Coating and cleaning of the Subaru Telescope mirrors

Takeshi Noguchi, Tomio Kanzawa, Tomio Kurakami, Saeko S. Hayashi, Masami Yutani, Norio Oshima, Masao Nakagiri, Kiichi Okita, Katsumi Imi, Robert Potter, Goro Sasaki, Yukiko Kamata, Tsuyoshi Ishikawa

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Proceedings Volume 4003, Optical Design, Materials, Fabrication, and Maintenance; (2000) https://doi.org/10.1117/12.391529
Event: Astronomical Telescopes and Instrumentation, 2000, Munich, Germany

Abstract

After the initial coating of the 8.3-m primary mirror of the Subaru Telescope in November 1998, we have conducted the first re-aluminization in August 1999. The primary mirror washing fixture worked efficiently for stripping the old coating and for washing the surface. Dry process is still to be improved. Suite of secondary and tertiary mirrors are being tested at the telescope, two of which were coated in- house, one in silver for the infrared observations and the other in aluminum for the optical observations, respectively. Evaluation of the coating film is conducted in two methods. Using a portable microScan, the reflectivity and the BRDF numbers of the primary mirror is monitored. Reflectivity over a wide range of the wavelength is measured in the witness mirrors. The preliminary data shows reasonably good number for the telescope optics. The in-situ cleaning of the primary mirror with solid and gaseous CO₂ sprinkle arms is operating once every month. Next step for the coating chamber commissioning is to improve the heating capacity for silver coating of the infrared secondary and tertiary mirrors, and the experiment for silver coating is going.

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Takeshi Noguchi, Tomio Kanzawa, Tomio Kurakami, Saeko S. Hayashi, Masami Yutani, Norio Oshima, Masao Nakagiri, Kiichi Okita, Katsumi Imi, Robert Potter, Goro Sasaki, Yukiko Kamata, and Tsuyoshi Ishikawa "Coating and cleaning of the Subaru Telescope mirrors", Proc. SPIE 4003, Optical Design, Materials, Fabrication, and Maintenance, (20 July 2000); https://doi.org/10.1117/12.391529

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