Study On Wave-front Measuring Technique For Large Telescope System

Large telescope system plays quite an important role in space science and technology, military affairs and national defence etc. Meanwhile more precise large aperture optical component processing and testing techniques are confronted with flinty challenge.We present a detailed project of utilizing the wave-front testing method to test large telescope system, which is useful to widen measuring range, to keep higher space resolution and measuring precision, to accomplish real-time and fast measurement and lower cost etc.Compared with Star Test, Hartmann and Interferometer etc, the testing method of this project needs no work reference benchmark given by beaconing or standard large plane mirror, and its principle is novelty. Scanning and sampling wave-front of sub-apertures is fulfilled by the pentagonal prism light turning system set on movable rail which can move on the rail platform, Meanwhile, tiny leaning angles of pentagonal prism are measured by Wollaston twin-frequency interferometer in order to amend scanning light beam's turning errors. H-S sensor detects sub-apertures to get all the sub-apertures' average wave-front slopes, from which system errors including wave-front errors of scanning light beam turning and wave-front error caused by large telescope itself, then we obtain the wave-front is reconstructed with average wave-front slopes of sub-apertures to get large aperture wave-front surface so that manufacture error and fixed error are analyzed to assure and improve imaging quality of large telescope system.We mainly analyzed the complex situation that light beam turning wave-front changes when pentagonal prism with manufacture angle errors and tiny 3-D angleschanges caused by mechanism movement. Computer simulation shows that wave-front change caused by manufacture angle errors and mechanism movement errors are separable. A method to measure and separate light turning wave-front change through pentagonal prism with manufacture angle errors and movement error is presented. It avails pentagonal prism light turning system to fulfill its best performance in wave-front testing of large telescope system.H-S wave-front testing technique and the method to wipe off system errors including light beam turning error are also analyzed and simulated by computer,.This thesis is a base fbr fuftfierstudying wave-front test on large telescope systems.