Active Optics in Astronomy: Freeform Mirror for the MESSIER Telescope Proposal
Active Optics in Astronomy: Freeform Mirror for the MESSIER Telescope Proposal
复制标题
天文学中的主动光学：用于梅西尔望远镜提案的自由曲面镜
DOI：
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发表时间：
2018
影响因子：
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通讯作者：
E. Muslimov
中科院分区：
文献类型：
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作者：
G. Lemaitre;P. Vola;E. Muslimov
天文学中的主动光学技术提供高成像质量。本文致力于高度可变形的主动光学，可以产生非轴对称的非球面或自由曲面，通过使用最少数量的致动器。非球面镜是从一个单一的均匀负载，作用在一个封闭形式的基板的表面，同时在轴向反应，其椭圆周边环在球面抛光。MESSIER空间计划是一个宽视场低中心遮挡折叠双反射镜天文望远镜，或简称为三反射镜天文望远镜（TMA）。光学设计是折叠反射施密特。望远镜的基本特征是36厘米口径，f/2.5，1.6° × 2.6°视场和弯曲视场探测器，允许漂移扫描观测的零畸变像差。自由曲面镜是由球面应力抛光产生的，在弹性松弛后提供超抛光的自由曲面。初步的分析需要使用三阶像差的光学理论和薄椭圆板的弹性理论。最后的交叉优化进行了Zemax射线跟踪代码和Nastran有限元弹性代码，以确定完整的几何形状的玻璃陶瓷Zerodur可变形基板。
Active optics techniques in astronomy provide high imaging quality. This paper is dedicated to highly deformable active optics that can generate non-axisymmetric aspheric surfaces—or freeform surfaces—by use of a minimum number of actuators. The aspheric mirror is obtained from a single uniform load that acts over the surface of a closed-form substrate whilst under axial reaction to its elliptical perimeter ring during spherical polishing. MESSIER space proposal is a wide-field low-central-obstruction folded-two-mirror-anastigmat or here called briefly three-mirror-anastigmat (TMA) telescope. The optical design is a folded reflective Schmidt. Basic telescope features are 36 cm aperture, f/2.5, with 1.6° × 2.6° field of view and a curved field detector allowing null distortion aberration for drift-scan observations. The freeform mirror is generated by spherical stress polishing that provides super-polished freeform surfaces after elastic relaxation. Preliminary analysis required use of the optics theory of 3rd-order aberrations and elasticity theory of thin elliptical plates. Final cross-optimizations were carried out with Zemax raytracing code and Nastran FEA elasticity code in order to determine the complete geometry of a glass ceramic Zerodur deformable substrate.