In order to realize the alignment of large aperture telescopes, the RC telescope alignment techniques were investigated based on the image processing and analysis of out-of-focus stellar images.Firstly, the relationship between the disalignment comas due to decentered or tilted errors and the centers of contour circle was analyzed according to transversal aberration. The decrease of ellipse eccentricity with the increase of major axis length caused by residual astigmatism were investigated after removing the coma. Then, the dependence of spherical aberration caused by longitudinal errors on the least circle radius of defocused stellar image was analyzed. Finally, the analysis above was verified by the emulation of Zemax modeling and how to use the out-of-focus stellar image to guide the alignment process and how to process the image were discussed. Experimental results indicate that both the lateral and longitudinal errors are well consistent with the theoretically analyzed results. The precision errors of coma and astigmatism adjusted respectively by tilt and eccentricity are both less than 5 ％.%为了实现大口径望远镜的装调,基于离焦星点图的图像处理和分析,研究了RC式望远镜的装调技术.首先,根据横向几何像差分析离焦像点图像和系统装调误差之间的关系,重点讨论了横向误差中离心和倾斜导致的偏心彗差和内外轮廓圆的圆心位置偏离距离的关系,以及彗差消除后残余的像散导致外轮廓椭圆的偏心率随长轴增大而逐渐减小的特点.然后,分析了主次镜之间纵向误差导致的球差和最小圆半径大小的关系.最后,应用Zemax建模仿真验证了上述分析,总结了如何应用离焦星点图指导装调过程以及图像处理的方法.实验结果表明:无论是横向误差还是纵向误差,应用该方法得到的实验结果和理论分析值均符合得很好,其中通过倾斜调整彗差和偏心率调整像散误差均可控制在5%以内.
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