离轴三反系统的装调主要采用初始定位与计算机辅助装调相结合的方法，实际加工过程中由于检测手段的限制，使得离轴量以及离轴角的控制精度较低，根据加工提供的离轴量参数并以其背部平面为基准进行反射镜初始定位会引入较大的初始像差，用计算机辅助装调无法收敛。基于自准直原理，进行反射光路分析，得出离轴反射镜位置与反射像位置的数学关系，并基于以上数学关系提出一种可精确测量离轴反射镜离轴量以及离轴角的系统，该系统包括高精度90°直角弯板、高精度直线导轨、中心定位特种工装、内调焦望远镜以及测微光管，其测量离轴量以及离轴角的精度分别为±0.05 mm和±10″。

The alignment method of off-axis three-mirror anastigmat combines initial positioning and computer-aided alignment. During manufacturing, due to the limit of testing methods, the off-axis fabrication and off-axis angle cannot be measured precisely. The initial positioning based on the manufacturing off-axis parameter can bring large initial aberration, which can not be converged when using computer-aided alignment. The optical path is analyzed based on the auto-collimation principle, and the mathematic relationship between the position of off-axis mirror and the reflected image is derived. A system based on the relationship is given to measure the off-axis fabrication and off-axis angle, it includes the right angle plate of high precision, linear guides of high precision, the special center orientation tool, internal focusing telescope and self-standardized micro-flat optical tube. The measurement accuracy of off-axis fabrication and off-axis angle is ±0.05mm and ±10″ respectively.