## Info

7.6.2 Non-Centered Systems and Circular Vase-Form Primary

With a non-centered system, the shape of the primary mirror is represented by (see 5.20c)

Fig. 7.9 True proportion vase form as the primary mirror of a reflective Schmidt. MDM in Zerodur vitroceram. Poisson's ratio v = 0.240. Geometry b/a = 1.150, t2/t\ = (1//)1/3 = 2.808 [from (7.47)]. (Up) Co-addition of Cv 1 and Sphe3 modes for a centered system used off-axis. (Down) Co-addition of Astm 3 and Astm 5 modes for a non-centered system

Fig. 7.9 True proportion vase form as the primary mirror of a reflective Schmidt. MDM in Zerodur vitroceram. Poisson's ratio v = 0.240. Geometry b/a = 1.150, t2/t\ = (1//)1/3 = 2.808 [from (7.47)]. (Up) Co-addition of Cv 1 and Sphe3 modes for a centered system used off-axis. (Down) Co-addition of Astm 3 and Astm 5 modes for a non-centered system

Zopt

29Q3 cos i

- [3(1 - t)p2 - 3tp2cos2d - (1 - 2t)p4 + 2tp4cos20], (7.48)

where t = | sin2 i. For a non-folded Schmidt, the incident angle of principal ray is i = <Pm + 1/4Q (cf. Chap. 4). With the denotation of Sect. 7.2 in this chapter, let us define the mirror coefficients Anm as

Setting the radius aperture at the inner ring radius, rm = a, we can derive from Sect. 7.2, the FCkk for each of these modes. As for previous centered systems it is also possible to find a co-addition of Cv 1 and Sphe 3 that does not require radial arms i.e. ZFC,k = 0 for these modes. This is obtained by substitution of

0 0