1m望远镜主反射镜的支撑和装配

Supporting and assembling for primary mirrors of 1 m aperture telescopes

考虑大口径光学望远镜中主反射镜的支撑精度直接影响光电探测设备的整机性能,本文根据光学系统对口径为1 000mm的主镜的支撑精度要求和光电设备中主镜的使用情况,采用轴向和径向组合支撑的结构形式来完成对主镜的支撑,并通过有限元法对支撑位置进行理论分析和计算。实验显示,在轴向18点浮动支撑、径向3点柔性支撑的情况下,主镜能够达到较高的面形精度。针对传统装调工艺不能获得理想的面形精度,探索了新的主镜装调方法。用干涉仪对带有支撑的主镜进行实时测量并进一步进行修磨,使主镜在装配完成后达到λ/18的面形精度。该方法满足了本项目的指标要求,也为更大口径主镜的装调提供了一种新的思路。

As the support accuracy of primary mirror of a large caliber optical telescope directly influ- ences the overall unit of opto-electrical detecting equipment, this paper presents a support structure combined an axial support and a radial support for the primary mirror with a diameter of 1 000 mm ac- cording to the requirements of an optical system for support accuracy. Furthermore, the finite element method is used to analyze and calculate the support positions theoretically. Experiments show that when a 18-point floating support is used in the axial support and a 3-point resilient mounting in the ra- dial support, the higher surface figure accuracy for the primary mirror can be reached. As traditional assembling and adjusting techniques can not reach the ideal surface figure accuracy, it explores a new assembling and adjusting approach to the primary mirror. An interferometer is applied to the measure- ment of the primary mirror with a support in real-time, then it is grinded again to obtain the higher accuracy. After the primary mirror is assembled, its surface figure accuracy reaches λ/18. The results not only meet the index requirements of the project, but also offer a new way to assemble and adjust larger caliber primary mirrors.