South Pole Telescope Design
SPST152 is an attempt to modify SPST148 to provide an image of the primary inside the dewar.
Figure 1. --- Side view, all fields. Two mirrors have been added to provide image of primary inside dewar.
Figure 2. Large side view, center field only.
Figure 3 --- Detail of Fig. 1. Some interference between beams inside dewar.
Figure 4. --- Detail of Fig. 2
Figure 5 - Dewar window for both SPST148 and SPST152. Only 240mm in diameter. Window is at an astigmatic approximate image of primary.
Figure 6 - Front view, all fields.
Figure 7 - Spot diagram for SPST152
Figure 8. Full-field spot diagram
Figure 9 - rms vs. field for 2mm wavelength. Does not achieve 1/10th wave at 2 mm wavelength.