Active Optics in LAMOST

• Published in: Chinese journal of astronomy and astrophysics Vol. 4; no. 1; pp. 1 - 9
• Main Authors: Su, Ding-Qiang, Cui, Xiang-Qun
• Format: Journal Article
• Language: English
• Published: IOP Publishing 01.02.2004; Department of Astronomy, Nanjing University, Nanjing 210093%Department of Astronomy, Nanjing University, Nanjing 210093; National Astronomical Observatories/NIAOT, Chinese Academy of Sciences, Nanjing 210042
• Subjects: 光纤望远镜; 活性光学; galaxies: distances and redshifts - techniques: active optics -telescopes - instrumentation: adaptive optics
• ISSN: 1009-9271
• DOI: 10.1088/1009-9271/4/1/1

Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is one of the major national projects under construction in China. Active optics is one of the most important technologies for new large telescopes. It is used for correcting telescope errors generated by gravitational and thermal changes. Here, however, we use this technology to realize the configuration of LAMOST, -a task that cannot be done in the traditional way. A comprehensive and intensive research on the active optics used in LAMOST is also reported, including an open-loop control method and an auxiliary closed-loop control method. Another important development is in our pre-calibration method of open-loop control, which is with some new features: simultaneous calculation of the forces and displacements of force actuators and displacement actuators; the profile of mirror can be arbitrary; the mirror surface shape is not expressed by a fitting polynomial, but is derived from the mirror surface shape formula which is highly accurate; a proof is given that the solution of the pre-calibration method is the same as the least squares solution.