大口径太阳望远镜消杂散光结构热效应集成技术研究

It is prevalence for the large aperture solar telescope to observe the Sun with a small view field. Surrounding the small view field is still the Sun, which is an intense source of both heat and stray light. For such a situation, the thermal design and the elimination of Stray light need to be optimized simultaneously. Owing to thermal control system cannot meet the demands of optical design for most of solar telescopes, the integrated analysis can contribute to perform high spatial resolution and high signal to noise ratio observations of the Sun. Therefore, a method on thermal-scattering integrated analysis of large aperture solar telescope is brought out. Based on DSO( Deepspace Solar Observatory) with a Φ1m mirror, the main task of the proposal is to study the impact of thermal effect caused by baffle structures to the validity of thermal design. A model with thermal control system, optical elements, and structural elements are set up in thermal analysis software and stray light analysis software. Accordingly, the theory of thermal-scattering integrated analysis about the baffle structures in solar telescope is adopted in this project. With the simulation and experiment, the thermal effect caused by the baffle structures in DSO will reach quantitative results as three major factors changed. The first is the geometry of baffle structures. The second is the material of baffle structures. The third is surface characteristic of the baffle structure. The thermal-scattering integrated design of baffle structures will be a key technique, which will provide reference for the future DSO optimal design on baffle structures and thermal control system.

大口径太阳望远镜对日局部视场观测存在极强的杂散光源和热源，望远镜热控系统和消杂光系统需要同时优化。本课题鉴于太阳望远镜热控设计一直难以完全满足光学设计的要求而成为制约光学性能提高的现状，深入开展太阳望远镜消杂散光结构热效应集成技术的研究。以1m口径的深空太阳望远镜为研究实例，建立大口径太阳望远镜的热、光、机结构的热模型，制定热-杂散光集成分析的研究方案，分析消杂散光结构附加热效应对望远镜热控有效性的影响。通过改变消杂散光结构的几何形式、材质选取和表面特性等参数，运用热分析软件和杂散光分析软件定量地分析系统热效应的变化规律，并通过实验论证表面特性参数，为深空太阳观测台消杂散光结构和热控的优化设计提供依据。对确保望远镜获取高空间分辨率、高信噪比图像具有重要意义。

大口径太阳望远镜消杂散光结构热效应研究技术是一种可以改善系统成像分辨率、提高信噪比的集成设计技术。该技术针对大口径太阳望远镜局部视场观测时，视场外的太阳光进入望远镜系统内成为强热源和强杂散光源并直接影响望远镜成像分辨率与信噪比的特殊情况，开展了消杂散光结构的热效应集成研究。本项目通过理论探讨与数值模拟方法对大口径太阳望远镜中典型的消杂散光结构的附加热效应展开了研究。首先，探索了大口径太阳望远镜观测特点、不同观测形式的太阳望远镜在热控与消杂散光方面的异同点，在此基础上探索了消杂散光与热控的理论关联，发现消杂散光的关键性因子GCF（Geometry Composing Function）、BRDF（Bidirectional Reflectance Distribution Function）和热控的辐射角系数、热控涂层相似且相关——会影响望远镜的热特性，奠定了太阳望远镜消杂散光结构热集成设计的理论基础。其次，本项目以1m口径的空间太阳望远镜SST(Space Solae Telescope)主光学望远镜MOT（Main Optical Telescope）为具体研究对象，深入考察了SST MOT内遮光罩、叶片的不同GCF参数以及主镜筒壁面BRDF特性参数对望远镜主反射镜、主焦面温度特性的影响。研究结果表明：SST MOT中增加消杂散光结构将改变主反射镜与主焦面的温度特性，是热控设计不可忽视的环节。内遮光罩的高度、叶片的高度、倾斜角和间距成为主要的GCF类参数；主镜筒壁面的微平面间距与倾斜角成为主要的BRDF类参数。从具体数值上来说，这些参数并非取值越小越好，结合三种消杂散光措施的附加热效应，分别提出了不同参数的热集成优化取值区间。最后，本项目还探索了大口径太阳望远镜消杂散光结构热优化集成设计方法，提出探索消杂散光结构针对太阳望远镜不同的口径、视场及轨道等因素的热敏感性。此外，本项目还初步探讨了SST热控方案对DSO（Deep-space Solar Observatory）的适用性。提出了大口径太阳望远镜主焦面组件的结构设计来解决排散大密度热流的热控难点。以上这些研究成果的获得为大口径太阳望远镜消杂散光结构热效应的后续研究提供了理论基础。