偏轴两镜系统的设计

用解析方法求出消除中心视场球差、彗差及像散的偏轴两镜系统的结构及面形参数．根据解出的参数进行光线追迹，得到中心视场像斑尺寸在０．２″以内．要改善边缘视场的像质，需要在双曲率面镜上加高次项，并偏离解出的某些参数．对于Ｆ／１１左右的系统，可以得到±０．６°视场边缘有１．５″～１．９″的像斑角尺寸．这种系统的子午与弧矢焦距不等，相差在１％以内．

Design of a Tilted Two-Mirror Optical System

The constructional data and surface parameters of a tilted two-mirror optical system with eliminated spherical aberration, coma and astigmatizm at the center of the field may be sloved by analytic method. By ray tracing with those solved data, the image size at the center of the field is less than 0.2 arc second. For reducing the image at the outter part of the field, it is necessary to add higher order terms in the equation of the bicurvature mirror, and at the same time deviate some parameters solved by equations. For an F/11 system, we may expect 1.5″～1.9″ image spot size at ±0.6° field. The meridional and sagittal focal lengthes of such a system are not equal, the difference being less than 1%.