The optical system is one of the core components for star sensors, whose imaging quality directly influences the performance of star sensors for star detection, thereby determining the attitude control accuracy of spacecrafts. Here, we report a new type of optical system with a catadioptric structure and a large entrance pupil diameter for a 15-magnitude star sensor. It consists of an improved Cassegrain system (R-C system), an aperture correction spherical lens group and a field of view correction spherical lens group. By embedding the secondary mirror of the R-C system into the output surface of the negative spherical lens of the aperture correction spherical lens group, the blocking of incident light is eliminated from the secondary mirror holder. After the structure optimization, the catadioptric optical system (COS) had a spectral range of 450 nm–950 nm, an entrance pupil diameter of 250 mm, a half-diagonal field of view of 1.4° and a focal length of 390 mm. By using theoretical calculations and experimental measurements, it was verified that the COS, with the ability to correct astigmatism, lateral color and distortion, can fulfill the detection of 15-magnitude dark stars.

中文翻译：

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大进瞳直径的15幅星形传感器的非折射光学系统设计

光学系统是恒星传感器的核心部件之一，其成像质量直接影响恒星传感器检测恒星的性能，从而决定航天器的姿态控制精度。在这里，我们报告一种新型的光学系统，该光学系统具有折反射结构，并且入射光瞳直径较大，适用于15幅星传感器。它由改进的Cassegrain系统（RC系统），孔径校正球面透镜组和视场校正球面透镜组组成。通过将RC系统的辅助反射镜嵌入到孔径校正球面透镜组的负球面透镜的输出表面中，可以从辅助反射镜支架中消除入射光的阻挡。结构优化后 折反射光学系统（COS）的光谱范围为450 nm–950 nm，入射光瞳直径为250 mm，半对角视场为1.4°，焦距为390 mm。通过理论计算和实验测量，证实了COS具有校正像散，横向颜色和畸变的能力，可以完成对15级暗星的探测。