Exact optics: a unification of optical telescope design
Abstract
A perfectfocus telescope is one in which all rays parallel to the axis meet at a point and give equal magnification there. It is shown that these two conditions define the shapes of both primary and secondary mirrors. Apart from scale, the solution depends upon two parameters: s, which gives the mirror separation in terms of the effective focal length, and K, which gives the relative position of the final focus in that unit. The two conditions ensure that the optical systems have neither spherical aberration nor coma, no matter how fast the F ratio. All known comafree systems emerge as approximate special cases. In his classical paper, K. Schwarzschild studied all twomirror systems for which the profiles were conic sections. We make no such a priori shape conditions but demand a perfect focus and solve for the shapes of the mirrors.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 August 2002
 DOI:
 10.1046/j.13658711.2002.05486.x
 arXiv:
 arXiv:physics/0203082
 Bibcode:
 2002MNRAS.334..787L
 Keywords:

 instrumentation: spectrographs;
 telescopes;
 Physics  Optics
 EPrint:
 11 pages, LaTex ([alleqno,epsfig]{mn}), 7 Figures (eps), accepted by MNRAS