极轴式望远镜主镜支撑结构对镜面变形的影响

根据极轴式望远镜的工作特点，以口径为700 mm的极轴式望远镜主镜室系统为例，确定了一套主镜支撑方案。借助于有限元分析软件MSC.Patran详细地建立了系统的有限元模型，选取多种工况，分析了系统在自重作用下的镜面变形情况，绘制了镜面变形误差PV值和RMS值的变化曲线。结果表明:镜面变形主要受角的影响，随着的增大而减小，径向支撑效果优于轴向支撑效果，镜面变形误差满足设计指标要求。在主镜室系统竖直放置时，利用Zygo干涉仪测得带支撑结构的镜面变形误差RMS值为28.48 nm，表明主镜在该支撑结构作用下的面形接近于加工检测时的状态，同时也验证了有限元模型的准确性。

Impact of the supports of primary mirror in equatorial telescope on its surface deformation

According to the working characteristics of equatorial telescope,the supports scheme on 700 mm primary mirror were designed.The finite element model of the system was established by the software MSC.Patran.The surface deformation under gravity was analyzed in different load cases.The curves of surface deformation errors PV and RMS were plotted.As a result,the surface deformation is influenced mostly by angle α,and it decreases when the angle α rises.The effect of the radial support is better than the axial support.The surface deformation errors can satisfy the precision requirements.When the system is perpendicular,the test result of RMS is 28.48 nm by Zygo interferometer,which shows that the surface shape with the supports is close to the test state.It validates that the finite element model is accurate.