云南天文台2.4 m望远镜几何扭曲变化初步探究  

Preliminary Exploration of the Change of Geometric Distortion of the 2.4 m Telescope at Yunnan Observatories

作　　者：陈筱 郭碧峰 郑中杰[2,3] 彭青玉 Chen Xiao;Guo Bifeng;Zheng Zhongjie;Peng Qingyu(College of Information Science and Technology,Jinan University,Guangzhou 510632,China;Sino-French Joint Laboratory for Astrometry,Dynamics and Space Science,Jinan University,Guangzhou 510632,China;School of Mathematics and Computer Science,Guangdong Ocean University,Zhanjiang 524088,China)

机构地区：[1]暨南大学计算机科学系,广东广州510632 [2]暨南大学中法天体测量、动力学与空间科学联合实验室,广东广州510632 [3]广东海洋大学数学与计算机学院,广东湛江524088

出　　处：《天文研究与技术》2023年第4期323-332,共10页Astronomical Research & Technology

基　　金：科技部国家重点研发计划政府间国际科技创新合作项目(2022YFE0116800);中国载人航天工程巡天空间望远镜专项科学研究项目(CMS-CSST-2021-B08);国家自然科学基金(11873026,11273014,U1431227)资助.

摘　　要：几何扭曲(Geometric Distortion,GD)是电荷耦合器件(Charge-Coupled Device,CCD)高精度测量不可忽略的因素,通常需要细致的观测工作导出,这必然占用宝贵的观测时间。利用丽江观测站2.4 m望远镜观测密集星场的CCD图像,初步发现了图像几何扭曲随天顶距(Zenith Distance,ZD)的变化规律。具体地,本文参考Gaia DR3星表提供的位置信息并进行数据归算,改正了较差颜色折射(Differential Color Refraction,DCR)效应,求解出不同观测时间CCD的几何扭曲模型,并使用四阶多项式拟合。结果表明,CCD图像的几何扭曲与观测时的天顶距存在一定的相关性。在像素x方向,几何扭曲模型四次项x^(4),x^(3)y,x^(2)y^(2)和xy^(3)、二次项x^(2)和xy与天顶距存在较明显的线性关系;在y方向,与天顶距存在线性关系的系数项为四次项x^(4)和xy^(3)、三次项xy^(2)和二次项xy。Geometric distortion is a non-negligible factor for CCD high-precision measurement,which usually requires careful observational work to be derived,and inevitably takes up valuable observational time.This paper explores the change of geometric distortion with zenith distance by using the CCD image observed with the GMG-2.4 m telescope at Lijiang station.Specifically,we refer to Gaia DR3 catalog in data reduction,and correct the effect of differential color refraction(DCR).Then the geometric distortion models at different observational times are derived and are fitted with a fourth order polynomial.The results show that the geometric distortion models of the CCD frames are correlated with the zenith distance(ZD)of observational time.There are obvious linear relations between quadratic terms x^(4),x^(3)y,x^(2)y^(2),xy^(3),quadratic terms x^(2),xy and zenith distances in X coordinate;in Y coordinate,there are obvious linear relations between the quadratic terms x^(4),xy^(3),cubic term xy^(2),quadratic term xy of the geometric distortion models and zenith distances.

关 键 词：几何扭曲 天体测量 图像处理 天体测量定标 

分 类 号：P129[天文地球—天体测量]