中国科学院云南天文台机构知识库

由于1 m太阳望远镜主体、光电导行及终端仪器消旋平台等的结构特点,即使光电导行系统闭环后,望远镜长时间跟踪精度仍然较低。为了解决这一问题,首先根据望远镜的结构特点分析了跟踪误差随时间变化的原因,然后通过理论和实测分析了误差的变化特点,研究了如何通过相关算法检测望远镜折轴焦点F_3焦面的高分辨率成像观测系统中的图像移动量,并平滑高频分量,分离出低频分量以反馈给望远镜定位跟踪系统,进一步提高望远镜的长时间跟踪精度。最后进行了高分辨率成像观测系统中TiO通道闭环跟踪实验,实验表明,在4小时的闭环跟踪时间内,跟踪误差的均方根值为0.52″,表明通过折轴焦点F_3成像观测系统中的图像移动量对望远镜实行闭环跟踪能够提高望远镜的长时间跟踪精度。

Though NVST is equipped with an optical auto-guiding system,the tracking accuracy is still affected by the mechanical structure of telescope,guiding system and derotator platform. In order to correct the long-term tracking error caused by above factors and improve the tracking accuracy,the solar images on the F_3 focal plane are used. Images are cross-correlated in real time with a previously recorded reference image of the same observation target. The drive signal for the image motion is generated by long-term average of the positions of the maximum of the cross correlation. The experiment in Ti O channel of high-resolution imaging system in NVST shows the tracking error by feature tracking in four hours is 0. 52″（ RMS）. Thus this result can demonstrate that for NVST,long-term tracking accuracy can be improved by using the image motion on coude focal plane in closed-loop telescope tracking.