小视场CCD图像的几何定标  

Geometric Calibration for a Small CCD Field of View

作　　者：彭青玉[1] 

机构地区：[1]暨南大学计算机科学系

出　　处：《云南天文台台刊》2003年第3期42-46,共5页Publications of the Yunnan Observatoty

基　　金：国家自然科学基金资助项目(10273015).

摘　　要：针对长焦距望远镜CCD观测天然卫星的情况,导出了用两颗亮星作为定标时,CCD视场几何参数(比例尺和指向)测量的误差公式,进而设计了多定标星定标时正确的归算方案。新方案不仅对天然卫星的位置测量,也对同类型的小视场CCD位置测量具有指导意义。Natural satellites in our solar system are often observed for their positional measurements with a long focal length telescope.The advantages of using a long focal length telescope are obvious.For example,it can well expand some satellites in a CCD image near their primary planet because of its smallscale factor.Besides,only a simple model is needed to reduce the observations since its perfect quality in both optics and astronomy.Many observations have shown that the positional accuracy of a natural satellite obtained with a long focal length telescope is usually better than that with a meridian circle.For instance,for some bright Saturnian satellites (S3～S6) an accuracy about ±0.″08 could be reached,a better accuracy in the range of ±0.″04～0.″06could be reached.But the best accuracy is only ±0.″10 with a CCD meridian instrument.However,we should pay attention to its geometric calibration when a long focal length telescope is used to observe a natural satellite because we usually have no good position reference stars.Nowadays,a widely used calibration method is the 'Bright Satellite Method',i.e.the theoretical positions of some bright satellites,which usually have better theories than those for faint satellites,are used to determine the scale factor and orientation.Their research works of Harper et al. and Shen et al. show that modern theories for Saturnian satellites can assure the utility and rationality of this 'Bright Satellite Method'.In this paper,we give the formulae of solving the parameters of geometrical calibration for a small CCD field of view,and derive the formulae of their errors.Moreover,when more than two reference stars or satellites are available,these formulae show us how to design precisely an integrated reduction scheme.The scheme will be useful for the astrometric observation of some natural satellites and also for that of their optical counterparts of some extragalactic radio sources when a small CCD field of view is used.

关 键 词：天然卫星 几何定标 位置测量 CCD 视场 

分 类 号：P122[天文地球—天体测量]