提出了一种星敏感器光学系统弥散斑尺寸的测试方法，主要是利用平行光管、转台和CCD显微摄像系统组成弥散斑测量系统，采集图像后，采用双三次插值像元细分，提取图像中灰度值，依据瑞利判据计算弥散斑尺寸。通过实际测量和试验验证，光学系统0.8视场弥散斑测量精度可以达到0.5μm，重复测量精度可达0.2μm。

A method for measuring the size of the dispersed spot of star sensor optical lens is presented. A measurement system consisting of a collimator, a rotary table and a CCD cameral was implemented to measure dispersed spot. After a image is acquired, a method of bibubic interpolation pixel subdivision is used to pick up the gray value of the image, and the size of dispersed spot is calculated by Rayleigh criterion. The actual measurement and verification test show that the measurement accuracy of the dispersed spot in 0.8 FOV reaches 0.5μm,repeat measurement accuracy can reach 0.2μm.