PSSn在大口径望远镜误差评估中的应用

为了更好地对大口径望远镜进行误差分析以及分配，引入了由美国30 m望远镜（TMT）团队所提出的标准化点源敏感性（PSSn），来进行大口径望远镜的各项误差及其之间的协调与分配。为了更好地利用PSSn进行误差分配，首先根据其定义对PSSn的基本性质进行了研究，论述了PSSn作为全频域评价指标的优越性，然后与传统的评价指标（波前均方根）进行了比较，重点分析了PSSn的合成特性以及合成误差的特点，之后利用Zernike多项式分析系统静态误差与PSSn的关系，得到了不同的Zernike系数与PSSn之间的关系。对于系统的动态载荷，利用功率谱结合光学传递函数的方法来研究系统的光学特性并对实际的大口径波前做出了仿真研究，得到系统的PSSn从0.996下降到0.991。所做的研究可以更好地理解大口径望远镜的误差特性，同时也可以帮助系统工程师对大口径望远镜的误差进行更好的分配。

Evaluation of the performance of large telescope based on normalized point source sensitivity

To evaluate the performance of large telescope under different kinds of error source, the normalized Point Source Sensitivity (PSSn) was introduced, which is firstly studied by the group of Thirty Meter Telescope(TMT) team to balance all the deviation of the telescope and also budget the error. First and foremost, character of the normalized PSSn was studied specifying the advantage in the evaluation in all the frequency domain. Then, the PSSn was compared with the traditional metric(FWHM, Strehl ratio, MTF, etc.). And the multiplication property was discussed. Using of Zernike polynomials allowed linking PSSn to the static error faced by large telescope, and the dynamic one was linked to PSSn by MTF. Lastly, the method was applied to a large telescope. Under mechanical vibration, the PSSn of this telescope main mirror decreased from 0.996 to 0.991. It aimed to guide beginner in the field of large telescope in the error analysis field.