一个新的泛卡塞格林望远镜系统

将卡塞格林系统的主镜及次镜都取球面,在焦面前加2片以上改正透镜,而将作为密封窗的平行平板的一面加4次方项,可以设计出具有相当大视场,像质优良的新光学系统。平板上的4次方非球面是凹面性质,它的制造,在周边铰支而外加均布载荷时可以加工为球面,释放均布载荷后该面即弹回成所要的4次非球面。所以,此系统从光学工艺角度看只有球面和平面。文中设计了4个不同相对口径系统:F/3,F/5,F/8,F/10。口径和视场相同:φ=300mm,2ω=1°,像质都接近或达到衍射极限。

New pan-Cassegrain telescope system

A new optical system with a fairly large field of view and excellent image quality can be designed by making both the surfaces of primary and secondary mirrors in the Cassegrain system spherical, adding two or more correcting lenses in front of the focal plane, and adding a 4^th order term to one surface of the parallel plates as a hermetically sealed chamber. The aspheric surface of the plate with 4^th order term is concave, and it can be made spherical by grinding it with hinge support around and equal loads applied, and after the equal loads being released, the surface springs back to form the desired aspherical surface with 4^th order term. So, from the viewpoint of optical technology, this system has spheres and planes only. Four systems with relative apertures of F/3, F/5, F/8 and F/10 have been designed with the same effective diameter and field of view: φ=300 mm and 2 ω=1°, and the image quality is close to or reaches the diffraction limit.