上海天文馆双焦点可切换一米望远镜主焦点的天体测量精度评估  

Evaluation of Astrometric Performance at the Prime Focus of the Double-focus One-meter Telescope at the Shanghai Astronomy Museum

作　　者：方文奉 姚嵩 于涌[1,2] 王磊 单星美 慎露润 王琦 陈振东 林清 杜芝茂[3] 姚迦文 FANG Wen-feng;YAO Song;YU Yong;WANG Lei;SHAN Xing-mei;SHEN Lu-run;WANG Qi;CHEN Zhen-dong;LIN Qing;DU Zhi-mao;YAO Jia-wen(Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China;School of Astronomy and Space Science,University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Astronomy Museum(Branch of Shanghai Science and Technology Museum),Shanghai 201306,China)

机构地区：[1]中国科学院上海天文台,上海200030 [2]中国科学院大学天文与空间科学学院,北京100049 [3]上海天文馆(上海科技馆分馆),上海201306

出　　处：《天文学进展》2024年第2期362-370,共9页Progress In Astronomy

基　　金：国家重点研发计划(2022YFE0116800);国家自然科学基金(12073062)。

摘　　要：上海天文馆望舒天文台的双焦点可切换一米望远镜是目前国内建成的最大口径的科普天文望远镜。该望远镜采用人工切换主焦点和耐式焦点的双焦点设计方案,耐式焦点主要应用于大众科普的目视观测,主焦点配备了大靶面科学级CMOS终端,视场达到1.5°×1.1°。较大的观测视场除了适合开展重要的天象直播活动以外,还可以充分应用于新星和超新星巡天搜索、太阳系小天体和人造天体监测等科研课题的研究。基于实测资料,对该望远镜主焦点的天体测量精度进行分析评估,结果表明:对于信噪比大于5的星象,星象位置的重复测量精度优于0.1 pixel;当信噪比为30时,重复测量精度优于0.05 pixel。以高精度的Gaia DR3星表作为参考星表,分析得出该望远镜主焦点CMOS观测图像的非线性特征明显,归算时需要用到3阶(20参数)模型。对于测试观测资料,亮于15 mag的恒星观测精度约为0.05′′;观测精度随着星等变暗逐渐下降,17.5 mag的恒星观测精度约为0.1′′。The Double-focus One-meter Telescope,located at the Wangshu Observatory of the Shanghai Astronomy Museum,is currently the largest aperture telescope dedicated to popular science in China.The telescope adopts a dual-focus design scheme that allows manual switching between the prime and Nasmyth focus.The Nasmyth focus primarily serves visual observations for popular science,while the prime focus is equipped with a scientific-grade CMOS sensor,offering a field of view of 1.5◦1.1◦.The larger field of view is suitable not only for live broadcast events but also for extensive research on various topics such as surveys of novae and supernovae,investigations of small celestial bodies in the solar system,and monitoring of artificial satellites.The astrometric precison at the prime focus of the telescope was analyzed and evaluated based on actual observation data.The results indicate that for star images with a signal-to-noise ratio greater than 5,the repeatability of measured coordinates is better than 0.1 pixel.When the signal-to-noise ratio is 30,the repeatability improves to better than 0.05 pixel.Using the high-precision Gaia DR3 catalog as the reference,the analysis reveals the presence of significant non-linear characteristics in the observation images obtained at the prime focus of the telescope.Consequently,a 3-order model(20-parameter)is necessary for data reduction.For the test observation data,the observational precision for stars brighter than 15th magnitude is approximately 0.05′′,with the precision decreasing gradually as the magnitude becomes fainter.The observational precision for 17.5th magnitude is around 0.1′′.

关 键 词：望远镜 底片参数模型 精度分析 

分 类 号：P123.22[天文地球—天体测量]