Bout M, Lamy P, Maucherat A, Colin C, Llebaria A
Laboratoire d'Astronomie Spatiale, Centre National de la Recherche Scientifique, Boite Postale 8, 13776 Marseille Cedex 12, France.
Appl Opt. 2000 Aug 1;39(22):3955-62. doi: 10.1364/ao.39.003955.
To reduce the level of stray light in a new-generation externally occulted space coronagraph, we consider new concepts for its external occulter and its associated diaphragm and report extended measurements of their light-rejection properties. The experimental setup, which includes an artificial Sun, uses both photometric and CCD imaging techniques and permits the study of the sensitivity to misalignement of the instrument's performance. Conic occulters that have either a multithreaded or a polished surface are found to give performances superior to those of the classical three-disk system and further are highly tolerant to misalignement. Serrated diaphragms outperform circular ones, as the bulk of the diffracted light is diverted from the coronagraphic objective.
为降低新一代外部掩星式空间日冕仪中的杂散光水平，我们考虑了其外部遮光罩及其相关光阑的新概念，并报告了对它们的光抑制特性的扩展测量。该实验装置包括一个人造太阳，使用了光度测量和电荷耦合器件成像技术，并允许研究仪器性能对未对准的敏感性。发现具有多螺纹或抛光表面的锥形遮光罩的性能优于传统的三盘系统，并且对未对准具有高度耐受性。锯齿状光阑的性能优于圆形光阑，因为大部分衍射光会从日冕仪物镜转移开。
