Mersenne-Schmidt望远镜的优化设计

OPTIMIZED DESIGN OF THE MERSENNE-SCHMIDT TELESCOPE

在追求望远镜集光效率的努力中,三面反射镜的Mersenne-Schmidt望远镜系统具有明显的优越性,可应用于口径很大的大视场巡天工作.在三镜系统的设计中,三个反射面的形状,各反射面之间的相互位置,甚至于焦面的曲率半径均可作为设计变量,通过优化这些变量,可使该望远镜系统在很大的视场范围内获得十分优秀的成象性能.Willstrop在三镜系统的设计中,引进了各镜面形状的高次项,给出了两组设计实例,使望远镜在4°视场内的象斑尺寸小于0~″.31本文的优化设计,增加了设计变量,获得的结果表明,在同样的视场范围内最大象斑尺寸仅为0~″.157,从而使这一新型光学系统具有更为广阔的应用前景.

In the effort of pursuing greater light gathering efficiency, the obvious advantage of the three-mirror Mersenne-Schmidt telescope is that it can be used for large aperture astronomical survey work. During the design stage of a three-mirror Mersenne-Schmidt telescope, the mirror surface parameters, the sepe rations between each surface and the radius of focal plate can all be adjusted so that the system has a superior optical performance over a large field of view Willstrop presented two examples of this three-mirror system. However, he restricted design variables in the system, the optical performance is therefore limited. In this paper, more parameters are considered, optimization program is applied this results a 50 percent reduce of image size compared with willstrop's design. In the same time, the system focus is away from the focus of the third mirror, therefore the back ground noise is reduced. All these make the mentioned system more attractive.