Analysis and Optimization for a Focal Plane Mechanism of a Large Sky Area Multi-object Fiber Spectroscopic Telescope
The Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST), a national major scientific project in the process of construction in China, is a special reflecting Schmidt telescope with 4-meter aperture and 5°field of view. There are three sub-assemblies: the reflecting Schmidt correcting plate, the focal plane mechanism and the spherical primary mirror. The focal plane mechanism is the assembly by which the physical information of the celestial bodies can be obtained from optical spectroscopies. The static and dynamic performance of the focal plane mechanism have a significant effect on the ability of the telescope to obtain the optical spectra of various celestial bodies. So, with the help of ANSYS, the optimization of the focal plane mechanism according to the static and dynamic characteristics requested by specifications is presented in this paper, along with the analysis of truss number, deformation in different compensation positions and contribution to the total deformation of each component. The results of study show that a feasible and reliable design scheme can be achieved.