天然卫星的CCD观测与精准定位关键技术的研究

Under the four project supports from the NSFC, our research group has already accumulated much experiences and developed successfully some key techniques in precisely positional measurements of some planetary natural satellites, leading to several innovative achievements..The present project is expected to continue using several big-aperture optical telescopes at the domestic optical astronomy laboratory to take observations systematically of some natural satellites (such as Jovian satellites, Saturnian satellites and others). And we plan to study mainly some other key techniques in both imaging at the tangent plane by referencing the latest achievements in space astrometry of the Hubble Space Telescope, and photometry. Specifically, the rules of the geometric distortion for a telescope,the differential color effects from different filters will be studied deeply. And the calibration technique by CCD image overlapping will be refined further, with the increasing of positional precision in great degree for planetary satellites, especially for the great separation faint satellites (such as Iapetus, and Phoebe) from their primary planet. Besides, some important information on different reference systems will be derived by taking CCD observations for a bright star (such as a Hipparcos star) with respect to some planetary satellites. On the other hand, the photometric techniques and reducing methods will be futher developed based on our previous mutual event observations in the years of 2003 and 2009 for the Galilean satellites of Jupiter, so that the mutual events in 2015 for these satellites will be observed and reduced much better than ever before.. The execution of this project will have direct contributions to both orbital refinement of some planetary satellites and planetary physics. It has some fundamental and prospective importance for the ongoing space exploration and space navigation in our country.

在国家基金委连续多个项目的支持下，本项目组已有长期天然卫星观测与精确定位测量的经验积累和技术储备,取得了多项创新成果。在此基础上，我们拟继续利用国内光学天文开放实验室的几架大口径望远镜进行系统观测，借鉴哈勃望远镜空间天体测量的最新研究成果，重点开展天然卫星精准定位的切平面成像和测光中若干关键技术的研究。具体地，将深入研究CCD图像几何扭曲的规律性、不同滤光片观测的色差效应，完善CCD图像重迭定标技术，最大限度地提高行星卫星尤其是离行星较远的暗弱卫星的定位精度。同时也开展较亮恒星和主要卫星的高精度相对位置测量，为参考系研究提供重要信息；结合2003和2009年度观测木卫互掩互食的经验，深入开展高精度定位的测光技术及归算方法研究，迎接2015年木卫互掩互食天象的观测。项目的完成不仅对天然卫星的轨道理论和行星物理的研究有着直接的贡献，也对我国正在实施的空间探测、深空导航有着基础性和前瞻性的意义。

本项目四年内使用国内几架大口径望远镜（云南天文台1米、2.4米和山东大学1米望远镜）开展若干天然卫星（包括木卫1-4，6-9，土卫1-9，天卫1-5，海卫1-2），近地小行星（如Apophis等）的CCD观测，获得大量珍贵资料。也开展木卫、土卫互掩食天象的观测，获得了多条光变曲线。主要研究进展包括，1）在美加学者提出精确测定主带小行星距离的方法基础上进行了重新推导并获得精准公式，并进行了试验验证；2）提出图像几何扭曲（GD）测定方法并进行了理论和方法的改进，也实际应用于天然卫星和小行星的高精度的观测资料处理和分析；3）结合国际天体测量界的最新进展，利用新近释放的Gaia-DR1星表进行了观测资料的分析处理，获得了珍贵资料也提出了新的挑战。期间，参加了3次国际会议，接待了国际同行3人次。共发表各类期刊论文17篇，其中SCI论文9篇，此外已接受正在出版的SCI论文2篇。毕业研究生13名，其中博士毕业1名。在读研究生硕士生5名。较好地完成了本项目提出的任务并进行了良好的拓展。