Fig. 1. Lunar direct irradiance instrument

Fig. 2. The key factors affecting the acquisition of high-precision ground-based observation data

Fig. 3. Schematic diagram of the overall installation and adjustment principle of optical axis

Fig. 4. Integrated logic flow chart with optical axis

Fig. 5. Field experiment drawing of the same optical axis installation

Fig. 6. Schematic diagram of laboratory lunar simulation

Fig. 7. Schematic diagram of the same optical axis assembly adjustment error

Fig. 8. Schematic diagram of error principle of spot deviation from plane mirror center

Fig. 9. Laboratory transfer calibration field test diagram.

Fig. 10. The ratio of the irradiance value measured at 500 mm between a standard lamp and a low-light lamp

Fig. 11. Spectral irradiance value

Fig. 12. Schematic diagram of radiometric calibration of the laboratory lunar direct irradiance instrument

Fig. 13. Laboratory transfer scaling logic diagram

Fig. 14. Field test diagram

Fig. 15. Different date tracking cameras take pictures of the moon

Fig. 16. Lunar spectral irradiance diagram

Fig. 17. Inversion data and observation data relative error result plot

Fig. 18. Diagram of angular sensitivity field experiments

Fig. 19. Angular sensitivity result plot

Fig. 20. Diagram of the stability experiment results of the lamp source

Fig. 21. Schematic diagram of calibration distance measurement error