In 2004, the primary mirror, secondary mirror, tertiary mirror and NA2 port baffling was redesigned to reduce the amount of scattered light viewed by the CCD in SPIcam. The changes were made in response to a scattered light analysis of the telescope that revealed that the SPIcam focal plane (4.8 arcmin per side) received unobstructed views of multiple scattering surfaces in the telescope structure (Pompea et al. 2003, Proc. SPIE, 4842, 128). The current limiting FOV is set by baffling inside the NA2 port, which sets a 90% transmission at 0.1 degree diameter, or 6 arcminutes. A Zemax study shows that the current NA2 baffles allow for a circular aperature with a diameter of 366.5 arcseconds. Removal of the NA2 baffles could allow the uncorrected field of view to extend to 10.42 arcminutes (90% transmission). The next limiting element restricting this field is the tertiary (M3) internal baffle #5 (This is the second baffle above M3).
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