Research On Aberration Detection Technology Of Large Aperture Telescope

The imaging quality of ground-based large-aperture telescopes is affected by mirror misalignment errors during observation.The mirror misalignment error will lead to the decline of imaging quality and observation accuracy of the telescope,which makes it impossible for the telescope to reach the technical targets and to observe celestial bodies and space debris accurately.Therefore,aberration detection technology is needed to detect the aberration of the telescope,and aberration correction method is used to reduce the mirror misalignment,so that the telescope is in the best working state.The object of this paper is a catadioptric telescope with 2.5m aperture and 3 degree field of view.It is hoped that an aberration detection method without additional optical elements can be used to correct the misalignment error of optical elements by corresponding correction methods.The specific work is as follows:1.The aberration detection method of split curvature sensor is studied.Because of the space limitation inside the telescope,it is impossible to add additional optical elements in the optical system.Therefore,the traditional curvature sensor method which needs to add spectroscopic elements is no longer applicable.The method of curvature sensor is improved.The split curvature sensor can be used to detect the curvature only by splicing CCD.The problem of space limitation in large aperture telescope is solved.2.The Cassegrain system with 300 mm aperture and 0.6 degree field of view is designed to verify whether the aberration correction method can be applied to different kinds of optical systems.3.The aberration correction method of two-step sensitivity matrix method is studied.The accuracy of traditional sensitivity matrix method is low.The correction accuracy is improved by improving the calculation method of sensitivity function,the selection principle of Zernike coefficient and the number of times of correction.The two-step sensitivity matrix method is used to correct the Cassegrain system and the optical system with 2.5m aperture and 3 degree field of view.It is proved that the twostep sensitivity matrix method can solve the correction of mirror misalignment.The problem has sufficient accuracy.