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8. Catadioptric Telescopes and Cameras
Fig. 8.4. Geometry of secondary mirror diameter needed to cover field of radius 6 without
vignetting at outer edge. See Eq. (8.1.4).
To determine the size of the secondary, we use the geometry in Fig. 8.4. The
diameter
D2
, expressed in terms of the diameter of the corrector, is given by
D2 = D[k + 29F^(k((j - 1) + 1)].
(8.1.4)
Note that Eqs. (8.1.3) and (8.1.4) with d = 0 apply to the two-mirror telescopes
discussed in Chapter 6. Note also that Dj and
D2
can be expressed in terms of
rj
and F with the substitution F^ = F(p
—
k)/p. We now apply the results in this
section to some specific types of S ...