compound lens or lens system designed to be free of astigmatism and able to form approximately point images
例句
Design of four-mirror reflective anastigmat optic system[J]. 引用该论文 丁学专;王欣;兰卫华;刘银年.
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。
