Golay3望远镜系统的设计

Design of Golay 3telescope system

提出用Golay3稀疏孔径取代望远镜两镜系统中的主镜,以在保证望远镜角分辨率的同时减少系统的质量和体积。首先利用三级像差理论设计了一套两镜系统,其中主镜是球面镜,次镜是双曲面镜。用Golay3稀疏孔径代替主镜,分析了填充因子与子镜半径的关系。然后,通过Zemax程序对系统进行模拟,分析了系统的调制传递函数特性及点列图。最后,在次镜后加入两块熔石英校正镜,并优化校正镜表面曲率半径以及成像工作距离以改进视场。通过Zemax程序模拟发现:系统的截止频率随着主镜填充因子的减小而减小,从F=22.2%的114.5lp/mm到F=15%的97.7lp/mm,再到F=10%的77.8lp/mm;另外,在成像面之前加入校正镜极大地提高了系统的视场,在0.3°视场下,加入校正镜之前的最大像斑半径均方根值是加入后的2.5倍左右。

The primary mirror of a two-reflective system for a telescopy was replaced by a Golay 3 sparse aperture to reduce its weight and volume while remaining high angular resolution.Firstly,the two-reflective system with a spherical primary mirror and a hyperbolic secondary mirror was designed according to the third-aberration theory.Then,the primary mirror was substituted by a Golay 3 sparse aperture,and the relationship between fill factor and sub-mirror radius was analyzed.The whole system was simulated by Zemax software to obtain the Modulation Transform Function（MTF） and the spot diagram of the system.Finally,two silicon correcting lenses were inserted behind the secondary mirror to optimize the radius of the correcting lens and imaging distances and to improve the field of the system.By Zemax simulation,it is shown that the cutoff frequency of the system has been decreased from 114.5lp/mm to 97.7lp/mm and to 77.8lp/mm as the fill factor reduces from 22.2% to 15%and to 10%,respectively.Moreover,inserting the correcting lens in front of the image plane can greatly enlarge the field of the system,which shows the RMS value of maximum spot radius without correcting lens is about 2.5times larger than that with a correcting lens in the field of 0.3°.