太阳是地球能量的主要来源, 太阳活动和变化对地球影响极大。为了满足天文学家对太阳观测和研究的需求, 设计一种新型Lyman α和可见光双波段内掩式日冕仪(SCI日冕仪), 能够在121.6 nm和700 nm两个波段同时对日冕进行高分辨率成像观测。根据太阳在121.6 nm和700 nm日面与日冕的辐射特性确定仪器的参数, 给出了日冕仪的初始结构, 建立评价函数对初始结构进行优化。分析了日冕仪光学系统的成像性能和各个光学元件产生杂散光对成像性能的影响, 确定影响系统杂散光抑制水平的主要光学元件和机械结构, 提出了对光学元件表面粗糙度的要求, 给出了里奥光阑的位置和通光口径。还设计了日冕仪光学反射镜和光学分色镜的膜系结构, 实现了对内日冕在121.6 nm和700 nm两个波段的同时成像。实验结果表明: SCI日冕仪视场覆盖1.1~25个太阳半径(Rs, 取1 Rs=0.267°), 空间分辨率优于4.8″, 杂散光抑制水平在1.1Rs处优于10-6量级, 在2.5Rs处优于10-8量级, 满足观测需求。

The sun is the main source of Earth's energy. As such solar activity and changes have a great influence on the Earth. To meet the solar observation and research needs of astronomers, a new type of Lyman alpha and visible dual-band internal occulting coronagraph was designed to meet the needs of high-resolution imaging observation of the corona at 121.6 nm and 700 nm for space. Firstly, the parameters of the instrument were determined according to the radiation characteristics of the solar disc and corona in the 121.6 nm and 700 nm bands and the initial structure of the coronagraph was given. The initial structure was optimized by an evaluation function. The imaging performance of the coronagraph optics was calculated and the influence of various optical elements on stray light was analyzed. The main optical components and mechanical structure affecting stray light were determined and the position and surface treatment method of a Lyot stop were designed. The coating film structure of the optical components and optical chromoscope of the coronagraph were designed to achieve simultaneous imaging in the 121.6 nm and 700 nm bands. The design and analysis results show that the field of view (FOV) of the coronagraph covers a 1.1 (Rs=0.267 degrees) to 2.5 solar radius, the effective focal length of the system is 945 mm, the spot radius root mean square (RMS) of the entire field of view is less than 10 um, and the angular resolution is better than 4.8 arcsec. The stray light suppression level of the system is better than 10-6 at 1.1 Rs and 10-8 at 2.5 Rs.