Recently, the stray light coefficient testing equipment with long focal distance and large diameter developed by Testing Technology Research Center, XIOPM successfully passed the acceptance and has been delivered to CIOMP.

The stray light coefficient testing equipment with long focal distance and large diameter is mainly used to test stray light coefficient of large-diameter camera optical system. The equipment consists of five parts: target simulation system, slide adjustment system, target detection system, control acquisition software and control cabinet. Except inherited traditional stray light testing principle of surface source method (commonly known as black-spot method), the equipment also received improvement and adopted combination of large-diameter off-axis parabolic mirror and integrating sphere. It realized simulation of the infinity target with 2лsolid angle streamer and avoided stray light error introduced by large-diameter transmission-type optical system materials. In order to ensure contrast ratio of black-spot and white-spot in target simulator being 1:1000, the traditional Ox horn plug structure was changed into a new-type inside chamber light trap structure. This structure makes high contrast of target simulator realizable and final contrast ratio of testing target reaching 1:2000. Besides, the adoption of combined classification of bright light sources and 2 integrating spheres in the aspect of weak light detector calibration helps solve the difficulty of large dynamic range weak light detector calibration and realizes weak light detector calibration with 3000 times dynamic range linearity better than 2%, and final equipment stray light testing repetitive error better than 0.3%.

At the time of site acceptance, the said equipment tested stray light of optical system and the testing data won out over those of original testing equipment of XIOPM and CIOPM. Participating experts held the opinion that all technologies indexes of the stray light coefficient testing equipment meet the requirements of Equipment Research and Development Technology Agreement and unanimously agreed that it passed the acceptance and can be put into use normally.