利用中国古代月掩星资料研究地球自转速率长期变化的方法探索

ON THE METHOD OF STUDYING THE SECULAR VARIATION OF THE EARTH'S ROTATION RATE FROM THE LUNAR OCCULTATION RECORDS IN ANCIENT CHINA

我国古代有相当丰富的月掩星观测记录。因其未记录观测时刻,用它们来研究地球自转速率的长期变化是相当困难的。刘次沅率先引入“可见时间段”的概念,使这一问题的解决成为可能。本文对刘次沅所采用的方法进行了分析和评述,并在此基础上提出了“最或然二次曲线拟合法”以综合处理中国古代的月掩星资料,期望能得到较为客观、合理、精确的地球自转速率的长期变化值。

There are an abundance of the lunar occultation records in ancient China. Without the records of the obscrving times, it is fairly difficult to study the secular variation of the earthi's rotation rate from them. Using the idea of 'really visible time' introduced by Liu Ciyuan,this problem can be solved. In this paper, the analysis and comment of this method were made. On the basis of these analyses, the 'fitting method of the most probabie quadric curve' was suggested. It would study the lunar occultation records in ancient China comprehensively. An objective and precise result of secular variation of ear-th's rotation rate will be expected.