Shafer D R
Appl Opt. 1977 May 1;16(5):1178. doi: 10.1364/AO.16.001178.
A type of two-mirror telescope is described in which light leaving the secondary mirror is allowed to reflect off the primary mirror again before coming to the final focus. It is shown that this double bounce off the primary mirror results in a telescope that may be configured to be corrected for spherical aberration, coma, and astigmatism. In fact, there are four distinct families of designs that are anastigmatic, encompassing a wide variety of optical forms. The more interesting designs are described in detail, and some performance numbers are given.
描述了一种双镜望远镜，其中离开副镜的光在到达最终焦点之前被允许再次从主镜反射。结果表明，这种在主镜上的两次反射会产生一种望远镜，该望远镜可以被配置为校正球差、彗差和像散。实际上，有四种不同的无像散设计类型，涵盖了各种各样的光学形式。详细描述了更有趣的设计，并给出了一些性能数据。
