astigmation

1.The coma aberation and astigmation are rec t ified through carefully selecting the position of aperture stop and the paramete rs of the quadratic surface.

仔细选取系统光阑位置，选取二次曲面系数及二次曲面位置，可以校正系统参及。

2.As a practical example, an astigmation corrected scanning flat holographio concave grating (SFHCG) is designed and some results of the numerical and optical experiments are given.

给出一消SFHCG设计实例和用这块光栅所做实验结果。