n.无收差透镜
Design of four-mirror reflective anastigmat optic system[J]. 引用该论文 丁学专
Three-mirror anastigmat can not meet the requirement of reducing weight and compacting size in some circumstances. 常见的离轴三反系统已不能满足系统小型化、轻量化的要求。
A unobstructed four-mirror anastigmat system was proposed, which was modified based on three-mirror anastigmat and had compacter structure. 介绍了一种无中心遮拦的离轴四反射镜系统，由离轴三反系统改进而成，结构更加紧凑。
three-mirror anastigmat (TMA) system 三镜消像散系统（TMA）
Four-mirror-reflective anastigmat 离轴四反
off-axis three-mirror anastigmat 离轴三反射光学系统
