South Pole Telescope Design
8 December 2003

South Pole Telescope Design

SPST313

This model also has a shaped secondary.  Addition of a sixth mirror allows better placement of dewar.  Placement of chopper is precisely located at point where central ray of off-axis fields crosses the x = 0 plane.  Image quality is good at 2 mm over entire 1 degree diameter field of view, but operation at shorter wavelengths has been sacrificed to improve quality of Lyot stop image.

Figure 1 - Side view, all fields.

Figure 2 - Side view, central field only

Figure 3 - Detail of Fig. 1 in vicinity of chopper.  Quatinary is slightly convex.

Figure 4 - Detail of Fig. 2 near chopper.

Figure 5 - Detail of Fig. 1 near detector.  As usual, Lyot stop is 160 mm diameter and silicon lens is 400 mm diameter.

Figure 6 - detail of Fig. 2 near detector.

Figure 7 - Spot diagram, with 2 mm wavelength Airy disks.  This model is well-corrected at 2 mm wavelength, but smaller wavelengths have been sacrificed to improve quality of Lyot stop.

Figure 8 - rms wavefront error vs. field.

Figure 9 - Image plane