TPF-C Technology Plan - Exoplanet Exploration Program - NASA
TPF-C Technology Plan - Exoplanet Exploration Program - NASA
TPF-C Technology Plan - Exoplanet Exploration Program - NASA
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Chapter 1<br />
Back end coronagraph<br />
optics<br />
Y<br />
Z<br />
Secondary<br />
mirror surface<br />
Primary mirror<br />
surface<br />
Tertiary<br />
mirror<br />
surface<br />
X<br />
Z<br />
Figure 1-2. Raytrace diagram showing the overall optical layout of <strong>TPF</strong>-C, with side view<br />
(top) and front view (bottom).<br />
sensitivities to misalignments and polarization effects that would result from higher angles of<br />
incidence. The primary-secondary separation is 12 m, and the secondary mirror is also an offaxis<br />
mirror, elliptical in profile, but with major and minor axes of 83.0 cm and 36.5 cm,<br />
respectively. The effective focal length of the system is 146 m, providing a field-of-view of 3.6<br />
arcsec. As shown in Figure 1-3, the light from the secondary is directed by a flat tertiary mirror<br />
to an optical bench that lies underneath the primary. The optical bench houses a wavefrontcorrection<br />
system, followed by a coronagraph. Further details of the coronagraph optics are<br />
described in the subsequent sections of this document.<br />
6