Fig. 1. KBA microscope

Fig. 2. Space ray tracing principle

Fig. 3. Spot diagrams with the aperture stop placed on the first mirror at different object fields. (a) -2 mm; (b) -1 mm; (c) 1 mm; (d) 2 mm

Fig. 4. Spot diagrams with the aperture stop placed on the second mirror at different object fields. (a) -2 mm; (b) -1 mm; (c) 1 mm; (d) 2 mm

Fig. 5. Effect of pitch angle on spot diagram. (a) 0.0005'; (b) 0.01'; (c) 0.02'; (d) 0.08'

Fig. 6. Effect of pitch angle on effectiveradius of spot diagram

Fig. 7. Spot diagrams with -0.27' field angle under different focal shifts. (a) -80 mm; (b) -60 mm; (c) -40 mm; (d) -20 mm; (e) 0 mm; (f) 20 mm

Fig. 8. Effect of field angle on effective radius of spot diagram under different focal shifts

Fig. 9. Curve of effective radius of spot diagram with focal shift