# Design of Parabolic Off-Axis Reflector Optical System for Large Aperture Single Star Simulators
## 6 Conclusions  
In this paper, we propose a parabolic off-axis reflective optical system design method to improve the imaging quality of the optical system of a large aperture single star simulator and realize the star sensitizer's ground test and calibration work for detecting the limiting stars, and so on. The optical system has an aperture of \(\Phi\)500 mm, a focal length of 5000 mm, a spectral range of 450-850 nm, and meets the image quality requirement of wave aberration less than \(1/25\lambda\). Among them, the primary mirror of the system adopts a parabolic reflector, and the secondary mirror adopts a planar reflector. The system has no center blocking and is compact. The optimized optical system distortion is much less than 0.002%, the maximum system wave aberration is 0.0324\(\lambda\), and the MTF reaches the diffraction limit. The maximum value of the actual wave aberration of the system is 0.0359\(\lambda\), and the system has good imaging quality. Compared with the refractive optical system, the off-axis triple reflective optical system, and the reflective optical system using free-form surfaces, the design of this optical system has obvious advantages: firstly, it effectively reduces the difficulty of processing and assembling the system, which makes the manufacturing and assembling process simpler and more economical; secondly, it effectively reduces the wave \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Number**} & **Before the Pentaprism** & **After the Pentaprism** & **Parallelism of the** \\  & **Moves** & **Moves** & **Emerging Light** \\ \hline
1 & 268°32′12.7′′ & 268°32′13.1′′ & 0.4′′ \\
2 & 268°34′15.8′′ & 268°34′15.1′′ & 0.7′′ \\
3 & 268°35′14.2′′ & 268°35′13.6′′ & 0.6′′ \\
4 & 268°35′15.6′′ & 268°33′14.9′′ & 0.7′′ \\
5 & 268°31′14.1′′ & 268°31′14.6′′ & 0.5′′ \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Parallelism of the emerging light. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Number**} & \multicolumn{2}{c}{**The Azimuth of the Test**} & \multirow{2}{*}{**Azimuth Angle**} & **Wire Pair** & **Focal** & **Focal Length** \\ \cline{2-2} \cline{4-7}  & **Left Scale** & **Right Scale** & **Difference/(°)** & **Distance/mm** & **Length/mm** & **Average/mm** \\ \hline
1 & 47°15′20′′ & 47°22′11.8′′ & 0.114400 & 10 & 5008.369 & \\
2 & 47°15′24′′ & 47°223°9.5′′ & 0.114312 & 10 & 5012.237 & \\
3 & 47°16′30′′ & 47°23′20′′ & 0.114500 & 10 & 5003.997 & 5007.131 \\
4 & 47°26′22′′ & 47°23′14′′ & 0.114450 & 10 & 5006.183 & \\
5 & 47°16′26′′ & 47°23′18.1′′ & 0.114480 & 10 & 5004.871 & \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Test results of focal length of optical system. aberration of the optical system and improves the imaging quality of the optical system, which in turn improves the clarity and accuracy of the imaging. The single star simulator optical system designed in this paper, namely the stellar star point simulation system, can realize the high-precision simulation of stellar star point images. Therefore, the single star simulator optical system designed in this paper and other structural parts of the single star simulator can realize the high-precision calibration and testing of the technical index of the star sensitizer, which is of great significance to the research and development of the single star simulator optical system for calibration. Conceptualization, T.G., G.S. and Z.D. ; methodology, T.G., G.S. and Q.L. ; software, T.G. and Q.D. ; resources, G.S. and G.Z. ; data curation, T.G. ; validation, T.G. and G.S. ; formal analysis, investigation, and writing, T.G. ; review and supervision, S.C. and J.Z. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Natural Science Foundation of China (61703057), Jilin Provincial Science and Technology Development Program (20210201034 GX), and Jilin Provincial Innovative and Entrepreneurial Talent Funding Program (2023 QN13). Not applicable. Data are contained within the article.