Fig. 1. Structure model of light and small infrared camera

Fig. 2. Optical system model

Fig. 3. Mirror thermal deformation surface simulation flow

Fig. 4. Thermal deformation simulation analysis of primary mirror

Fig. 5. Simulation analysis of thermal deformation of the secondary mirror

Fig. 6. Thermal deformation simulation analysis of front mirror tube

Fig. 7. Optical system MTF value at room temperature

Fig. 8. Optical system MTF value after low temperature defocusing

Fig. 9. Optical system MTF value after room temperature focusing

Fig. 10. The optical system detects the optical path at low temperature

Fig. 11. Construction of beam expanding system

Fig. 12. The low temperature wavefront of the optical system

Fig. 13. Fine-tuned collimation of standard spherical rear system wavefront

Fig. 14. Optical system fixed focus test at room temperature

Fig. 15. MTF overfocus curve at room temperature

Fig. 16. Low temperature imaging optical path

Fig. 17. Schematic diagram of camera low temperature test

Fig. 18. Vacuum low temperature overfocus curve