白光日冕仪光学系统杂散光抑制

“夸父计划”是由“L1+极轨”的三颗卫星组成的一个空间观测系统，夸父A星中一个重要的仪器是白光日冕仪(2.5 R⊙ -15 R⊙ )，并且在我国是首次研制。日冕仪的工作特点决定了其对杂散光抑制要求及其严格。本文通过分析系统工作特点，设计了白光日冕仪，系统视场4度、角分辨率14角秒、口径30mm、焦距200mm、系统总长1080mm、其中光学系统370mm，37pl/mm的MTF值大于0.5；根据其杂散光抑制的结构特点，利用多个光阑互相共轭的空间位置关系，系统的四个主要杂散光光源从结构上被全部抑制，从而达到了良好的杂光抑制水平。

Study of the structure of the stay light suppressing of the white light coronagraph optical system

To meet the demands on suppressing strictly stray light for a coronagraph,a white coronagraph is designed based on its working principle and the properties of stray light. The white coronagraph shows its main specifications in the field of view of 2.5 R⊙ to 15 R⊙,a resolution of 14″,a aperture of 30 mm,a focal length of 200 mm,and the total length of 1080 mm.Furthermore,the length of optical structure is 370 mm and the MTF value at 37 pl/mm is above 0.5. The four kinds of stray light sources is analyzed in detail,which is direct sun light,the diffractive light of sun light at edge of an external occulter D1,the diffractive light of sun light at edge of a field stop A1,and the multi-reflection light in the objective O1.With the help of conjugated stops,a stray light suppressing structure is designed. Experiment results show that four main stray light sources are totally suppressed and the stray light suppressing level reaches 10-8-10-10 B⊙,which satisfies the system requirements.