望远镜光学镜面的红外扫描测温系统研究

With the increase of telescope aperture and high resolution observation ability，the tiny changes in temperature of telescope mirror will cause degradation of image quality. The performance requirement of thermal control system of optical element such as primary mirror from telescope designers is more and more high. The accurate measurement of mirror temperature distribution becomes the key factor to improve the performance of thermal control system. Due to the application limits of contact thermography to the mirror, non-contact infrared temperature measurement becomes the best choice of the temperature measuring of mirror. Mirror thermal radiation is feebleness signal and less than the thermal environment of specular reflection by mirror at the infrared temperature measuremen, it become the biggest obstacle to infrared imaging temperature measurement of mirror. . Temperature measurement system gather thermal radiation of mirror and eliminate the interference of environmental radiation and thermal radiation stray ligh by lens tube. The tube temperature is controlled by the temperature control system. The inner surface of Lens barrel covered with a layer of gold film. Combining with calibration technique of surface source blackbodyand and Samples of mirrorand 2D electric slide rail,the temperature measurement. system can accurately measure the mirror temperature distribution by infrared scanning temperature measurement technology. The research of project will provide a solution of infrared measuring temperature about telescope mirror and other metal surface. The research of the project is helpful to the thermal control system design of mirror and structural support for telescope especially solar telescope.

随着天文望远镜口径增大，高分辨观测能力的提高，望远镜光学镜面微小的温度起伏都会对像质产生影响。望远镜设计师对主镜等光学元件热控系统的性能要求越来越高，镜面温度分布的精准测量成为提高热控系统性能的关键因素。由于接触测温在镜面的应用限制，非接触红外测温技术成为镜面测温的最佳选择。红外测温时，镜面自身热辐射极弱且远小于镜面反射的环境热辐射成为镜面红外测温的最大障碍。 . 测温系统采用控温的金膜镜罩汇聚镜面的自身热辐射，消除环境辐射和热辐射杂散光的干扰。测温系统结合面源黑体与样镜的定标技术和二维电动滑轨，实现镜面温度分布的精准红外扫描测温。项目的研究将为望远镜的镜面和其它金属表面的红外测温提供一种解决方案，有助于望远镜特别是太阳望远镜的镜面、支撑结构等的热控系统设计。

镜面测温是天文望远镜主/副镜等光学元件闭环控温，改善镜面热气流扰动对像质影响的基础，但目前并没有可以准确测量镜面温度的仪器。镜面接触测温会破坏膜层，镜面背部的接触测温的不能准确反映镜面温度，传统红外测温装置对镜面的测温也极不准确。.本项目深入分析了镜面红外测温的难点，实测研究了传统红外测温装置对镜面红外测温能力的极限。成功研制出可精准测量光学镜面温度的镜面红外测温仪。.与传统红外测温装置相比，研制的镜面红外测温仪对镜面辐射的收集能力提升了一个量级，大幅度抑制了镜头辐射对测温精度的影响，还消除了环境辐射在镜面的反射干扰，对光学镜面的测温精度也提升超过一个量级。本项目补齐了太阳望远镜主、副镜闭环热控系统的关键一环：用镜面温度评估主镜热控效果，解决了长期困扰人们的光学镜面、金属表面等的红外精准测温问题。