Fig. 1. Fronhoffer circular aperture diffraction optical path diagram

Fig. 2. Diffraction effect with main aperture at rear

Fig. 3. Diffraction effect with main aperture in front

Fig. 4. Structure of stop system

Fig. 5. Schematic diagram of diffraction light imaging

Fig. 6. Experimental setup for diffraction effect measurement

Fig. 7. Total light image

Fig. 8. Diffractive light image with light blocking disc in different diameters

Fig. 9. Flat field correction of CCD

Fig. 10. Luminance curve at edge band of total light

Fig. 11. Diffracted light image after separation of outer ring with light block disk in different diameters

Fig. 12. Diffraction ring brightness curve

Fig. 13. Diffraction ring brightness curve after repair

Fig. 14. Diffraction effect curve