Fig. 1. Radiation power density of 6.0 MV under different colour temperatures

Fig. 2. Energy concentration corresponding to different Gaussian radius

Fig. 3. Changes of $S_{\text{NR}}$ with integration time under different apertures

Fig. 4. Number and probability of fixed-pose stars in field of view

Fig. 5. Optical path diagram

Fig. 6. Analysis of image quality

Fig. 7. Variation curves of focal length and defocusing distance with temperatures

Fig. 8. Design of light cover

Fig. 9. Image surface debugging and calibration

Fig. 10. Out-field stargazing test

Fig. 11. Stray light test