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Proceedings Paper

Design, manufacture, measurement, and installation of the gross mirror cell of the LAMOST Schmidt plate
Author(s): Dehua Yang; Kunxin Chen; Yongjun Liang; Shuqing Wang; Guohua Zhou
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Paper Abstract

The gross mirror cell of the LAMOST reflecting Schmidt plate supporting 24 hexagonal sub-mirrors with an alt-azimuth mounting has already been in routine operation for two years. During observation, the gross mirror cell must hold good structural stiffness and stability, meanwhile, lightweight, good transportability and accessibility for maintenance is implicitly required. This paper describes structural design principle, manufacturing, transportation, installation and measurement of the gross mirror cell. Based on diverse investigation of design scheme and aided with finite element analysis, we achieved an optimum mirror cell, which is actually a hybrid of space frame and truss structure of about 5.4 m by 6.3 m, which meets very well technical requirements with lightweight, high stiffness and clear accessibility. The truss part is supported on the space frame part with a few carefully chosen nodes. Bolted sphere connection is selected for truss nodes. That only commercial steel material is used and medium precision is defined lead to low manufacturing cost. During assembly at workshop and restoration at site, 3D laser tracker has been used to not only measure the 3×24 working nodes in the top layer truss but also aid the installation process of the mirror cell. The final measurement result is 0.3 mm RMS within the required 0.5 mm. The mirror cell was manufactured in Nanjing and transported to, ~1300 km away, LAMOST Xinglong station northeast to Beijing. In this paper, we also share special consideration for the long distance land truck transportation and experiences got during large-sized precise part like the gross mirror cell installation to 25 m high pier in situ.

Paper Details

Date Published: 10 July 2008
PDF: 9 pages
Proc. SPIE 7012, Ground-based and Airborne Telescopes II, 70124M (10 July 2008); doi: 10.1117/12.788969
Show Author Affiliations
Dehua Yang, National Astronomical Observatories, Nanjing Institute of Astronomical Optics & Technology (China)
Kunxin Chen, National Astronomical Observatories, Nanjing Institute of Astronomical Optics & Technology (China)
Yongjun Liang, National Astronomical Observatories, Nanjing Institute of Astronomical Optics & Technology (China)
Shuqing Wang, National Astronomical Observatories (China)
Guohua Zhou, National Astronomical Observatories, Nanjing Institute of Astronomical Optics & Technology (China)


Published in SPIE Proceedings Vol. 7012:
Ground-based and Airborne Telescopes II
Larry M. Stepp; Roberto Gilmozzi, Editor(s)

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