岁差常数改正及FK5和Hipparcos自行系统

Precessional Correction and the Proper-Motion Systems of FK5 and Hipparcos

许多研究结果表明,FK5和Hipparcos自行系统的关系,与VLBI和LLR所测定的岁差常数改正值不相符合．利用建立在FK5系统上的PPM和ACRS自行数据的分析,通过多个子样本的考察,发现不论由PPM或ACRS自行资料,都无法给出一致的岁差改正值和分点运动改正值．从而表明,FK5自行内部的系统差是产生这种问题的主要因素．

Comparing proper motions of the FK5 and Hipparcos, several authors declared that the two proper-motion systems are inconsistent with the value of the precessional correction obtained from VLBI and LLR observations. Based on the proper-motion data from the PPM and ACRS catalogues which are constructed on the FK5 system, the discrepant values of the precessional correction and of the correction of the equinoctial motion, derived from the different subsets of stellar samples, have be found. One of the reasons for those discrepancies should be mostly due to the internal biased proper-motion system of the FK5.