极紫外望远镜工作波段与可见光波段相差近两个数量级,其工作波段的衍射极限很低,达到30.036″,使该波段望远镜角分辨率的检测很困难。本文介绍了一种极紫外望远镜角分辨率的评价方法。该方法利用通用可见光波段面形检测仪器,检测出极紫外望远镜光学元件面形误差和装调误差,将检测到的与波长无关的Zernike系数代入光学设计程序,计算出极紫外望远镜工作波段的点扩散函数和环绕能分布,进而计算出望远镜在极紫外波段的角分辨率。实验结果表明,极紫外望远镜的角分辨率可以达到0.18″。该方法是一种快捷、有效的极紫外波段成像仪器的评价方法。
The Extreme Ultraviolet Telescope(EUT)'s operational wavelength band is smaller nearly two levels than that of the visible light and its in-band diffraction limit is very low, so it is very difficulty to measure a angular resolution in extreme ultraviolet band. In this paper a new evaluation method using ZYGO interferometer to test the figure error and alignment error of the EUT in visible light is introduced. Then, the Zernike coefficients independent of the operational wavelength are brought into the optical design software, so that the point spread function and diffraction encircled energy in operational wavelengths can be obtained by the optical software. Finally, the angular resolution of the EUT in extreme ultraviolet band is calculated by the relative parameters. Experimental results show that the evaluation method has the advantage of high speed and efficiency for an imaging apparatus in extreme ultraviolet band.