| 其他摘要 | When the large aperture optics telescope is working, the primary mirror contact with the atmosphere directly, pointing to the sky. After observation for long time, Some contamination such as dust particles in the atmosphere will continuously fell to accumulate on the primary mirror, deteriorate the reflectance of the telescope’s primary mirror, strengthen the stray light from primary mirror surface to the system detector. Cleaning the primary mirror regularly can Appropriate mitigation the speed of reduction of the of the primary mirror’s optical properties. In order to maintain the best observation effect on the astronomical telescope , every 2-3 years , recoating the primary mirror in large aperture astronomical optical telescope. In this dissertation,a research of coating the primary mirror in large aperture astronomical optical telescope is presented, use the first coating machine ZZ3200, which can deposition aluminum reflective film for large telescope primary mirror from the top to down. Discuss some problems respectively,such as the reflective film layer’s material, uniformity , molecular dynamics simulations of coating process, the structure of the vacuum chamber, the transporting and lifting of the primary mirror, old film stripping, cleaning for coating, etc. Finally, for coating the Lijiang 2.4-meter telescope primary mirror, which has the largest single block primary mirror in China in present, make the process arrangement about the primary mirror coating process of Lijiang 2.4 -meter telescope, and the security management and other documents, finally complete the coating of primary mirror in Lijiang 2.4 -meter telescope. Firstly, discuss the choice of material for coating metal reflecting film to primary mirror in astronomical optical telescope, depend on the layout of evaporation source in the ZZ3200 coating machine, discuss the nonuniformity of thickness of the Al coating, and the influence from the nonuniformity of thickness of the Al coating to the imaging quality of telescope. Study the protected film of the primary mirror of astronomical optical telescope, analyse the influence from protected layer to the reflectance of the primary mirror, from protected layer to the old film stripping. Use the structure of ZZ3200 coating machine, make molecular dynamics simulations of coating process. Make the process arrangement about the primary mirror coating process of Lijiang 2.4 -meter telescope, and the security management and other documents. Based on the above analysis, we complete the work of coating the primary mirror in Lijiang 2.4 -meter telescope use the ZZ3200 coating machine in October 2012, And customize in yunnan observatory 2.4 m telescope primary mirror coating specification and related process card. This research work will provide the reference for large astronomical telescope primary mirror coating in China In the future. By measurement of the accompany plated glass, the average reflectance in the range of 350 to 1100 nm is 87.16%. After complete the Al coating to primary mirror in Lijiang 2.4 -meter telescope, observation results show that the limiting magnitude increase more than one magnitude both imaging observation and spectrum measurement. |
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