Method acquiring telescope primary and secondary mirror alignment error based on astigmatism decomposition

Abstract

The invention relates to a method acquiring telescope primary and secondary mirror alignment error based on astigmatism decomposition. The method includes the steps of measuring four misalignment rates of a secondary mirror and the proportionality coefficient of exit pupil wavefront error astigmatism coefficient to coma coefficient, wherein the proportionality coefficient is expressed through a zernike polynomial, measuring a real-time exit pupil wavefront error, placing a misalignment rate dx and a misalignment ty of the secondary mirror in one group, placing a misalignment rate dy and a misalignment rate tx of the secondary mirror in one group, decomposing a astigmatism item Ast into Astx and Asty, constructing a relation model of the misalignment rates and the astigmatism item, solving a coupling coefficient Alpha x and a coupling coefficient Alpha y, constructing a relation model of the misalignment rates and a coma item, and solving the misalignment rates of the secondary mirror according to a constructed relation model of the misalignment rates and the wavefront error.

Description

technical field [0001] The invention belongs to the field of photoelectric detection, and relates to a method for decomposing and calculating alignment errors, in particular to a method for calculating alignment errors of primary and secondary mirrors of a coaxial reflection telescope based on exit pupil wavefront information. Background technique [0002] The alignment error of the primary and secondary mirrors of the coaxial reflective telescope will directly affect the optical characteristics of the entire telescopic system. In order to make the telescope work as designed as possible, the alignment errors of the primary and secondary mirrors need to be minimized as much as possible. Especially for large telescopes and space telescopes with a diameter of more than 1m, it is not convenient to manually align and adjust. If the alignment error of the primary and secondary mirrors is too large, the imaging quality of the telescope will be greatly reduced, or even make it imposs...

AI Technical Summary

Problems solved by technology

Han Xingzi, Yu Xin and others proposed to use the SPGD algorithm (Stochastic Parallel Gradient Descent Algorithm) aligns the secondary mirror of the coaxial three-mirror system when there is no wavefront sensor and the system parameters are unknown. For rigid body motion, the wavefront error caused by the misalignment of each degree of freedom is not the same, and the impact size is also different. The tilt error and centrifugal error may not converge at the same time, and the reliability and stability of the algorithm are not high.

Images