从共轴三反射系统的基本理论出发，通过偏瞳和偏视场相结合的方式设计了一个圆视场离轴三反射光学系统，全视场为5°，焦距f=5000 mm。从像质评价结果可以看出，系统成像质量接近衍射极限，满足指标要求。在设计中考虑到了实际工程应用中的部分问题，可以为长焦距大视场航天相机系统设计提供参考。

Based on the theory of offaxis threemirror ststem, an optical system with effective focal length of 5000 mm and field of view of 5° is designed. The image qualities of this system are near diffraction limit. Some factors in practical engineering application are taken into account in course of design, so that this system is very useful in the field of space optical remote sensing.