The angular values are comparable with those of Table 3.20 although the axial change ddx is ten times larger than the lateral decenter The right-hand column of Table 3.21 gives the axial despace effect on the field coma Sji, which will be derived in the next section.
188.8.131.52 Change in field coma Sjj. This effect can be important, above all in aplanatic telescopes with extreme image requirements (such as space applications); or in cases where an image shift is required and the spherical aberration is compensated by other means.
We require here the contribution of the secondary mirror to $11, i.e. ($17)2. This can be derived from the recursion formulae (3.336) and (3.337) or taken directly from (3.52):
Was this article helpful?