基于SVOM卫星VT望远镜的温度调焦方法  

Temperature Focusing Method Based on SVOM Satellite VT Telescope

作　　者：张健[1] 任国瑞[1] 邹刚毅[1] 祁宁[1] ZHANG Jian;REN Guorui;ZOU Gangyi;QI Ning(Space Optics Lab,Xi′an Institute of Optics and Precision Mechanics of CAS,Xi′an 710119,China)

机构地区：[1]中国科学院西安光学精密机械研究所空间光学技术研究室,西安710119

出　　处：《光子学报》2025年第2期134-142,共9页Acta Photonica Sinica

基　　金：中法合作天文观测项目。

摘　　要：SVOM卫星中的可见光望远镜(VT)遮光罩根部的热弹形变会拉扯次镜座,次镜座受力形变导致次镜座带动次镜在光轴方向移动,从而出现离焦。有限元仿真确认VT离焦量与遮光罩根部温度变化的关系为0.115 mm/℃。由于实际产品的非理想特性,试验测试离焦量与遮光罩根部温度变化的关系为0.050 mm/℃。试验数据表明,当遮光罩根部温度在5℃~20℃范围内时,VT离焦量与温度之间表现了较好的线性对应关系,离焦范围达到0.75 mm。同时,±2.0℃的温度控制精度能够满足±0.1 mm的景深要求。The main function of the Visible-light Telescope(VT)in the Sino French cooperative Space Variable Objects Monitor(SVOM)satellite is to perform high-precision observation of the afterglow of a Space Gamma Burst(GRB).VT is a large aperture,long focal length telescope.Due to differences in ground and space environments,the focal plane position needs to be adjusted during orbit.In the design of VT,the focus function is achieved by adjusting the position of the correction mirror using a focusing motor.In the testing of VT,we found that the thermal elastic deformation at the base of the VT outer baffle can pull the secondary mirror supporter,and causing defocusing of the telescope,but the image quality maintains good condition.According to the main structure design of VT,kinetic analysis shows that when one end of the outer frame of the outer baffle is restricted by a constant temperature barrel assembly,and the other end is pulled by the root of the variable temperature outer baffle,the pulled end will contract inward or expand outward,and the four secondary mirror seat ribs will tilt in the same direction along the optical axis under the drive of the outer frame,driving the secondary mirror to move forward or backward in the optical axis direction.If the temperature at the base of the outer baffle is consistent in the circumferential direction,the stress applied to the outer frame of the secondary mirror supporter is circularly symmetrical and points towards the optical axis.The secondary mirror will only move along the optical axis under the driving force of the ribs,without any deviation or translation,and will not change the parallelism and coaxiality of the primary and secondary mirrors,so the system image quality will not be affected.In addition,when one end of the outer frame of the secondary mirror supporter is limited,the outer frame and ribs form an inverted“L”shaped lever structure with the limited end as the fulcrum.The ratio of the displacement of the secondary mirror to the displacement of the outer

关 键 词：可见光望远镜 温度调焦 遮光罩 次镜座 能量集中度 

分 类 号：TH74[机械工程—光学工程]