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Proceedings Paper

Coating the 2-m level primary mirror with protected aluminum
Author(s): Wenjun Pei; Hongxiang Liu; Weichuan Du
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Paper Abstract

In order to evaporate the Ø 2.4m large-scale speculum, we have developed a high-vacuum resistance evaporation machine which is of the nation’s largest bell-type, and we first propose to use the structure of the protected-Al coating with SiO coating by evaporating from top to bottom. The results show that the non-uniformity of aluminum coating is no more than 5.17% within 1.8 meters in diameter, also after environmental testing, there is no change on the mirror surface, and the reflectance decreased less than 1%. The average of the speculum reflectivity is Rav<88%@350nm-1800nm and Rav<90%@ 400nm-2500nm.We have separately completed the Ø 1.8m plane mirror in April 2011 and the Ø 1.8m concave mirror in October 2011. The results show that the PV value is less than λ/10 after evaporation and the RMS value has no change.

Paper Details

Date Published: 15 October 2012
PDF: 7 pages
Proc. SPIE 8415, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, 841517 (15 October 2012); doi: 10.1117/12.966816
Show Author Affiliations
Wenjun Pei, Institute of Optics and Electronics (China)
Hongxiang Liu, Institute of Optics and Electronics (China)
Weichuan Du, Institute of Optics and Electronics (China)
Graduate School of the Chinese Academy of Sciences (China)


Published in SPIE Proceedings Vol. 8415:
6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes
Wenhan Jiang; Myung K. Cho; Fan Wu, Editor(s)

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