由南北朝以前月掩恒星观测得到的地球自转长期加速

ACCELERATION OF THE EARTH'S ROTATION OBTAINED FROM RECORDS ON OCCULTATION OF STARS BY THE MOON BEFORE 600 A. D. IN CHINA.

本文对我国早期(南北朝以前)的月掩恒星记录使用了"实际可见时间段"的方法,首次利用这些未载时刻的记录得到地球自转长期加速的平均值ω.83个精选的月掩星记录得到ω=—49.7±4.2秒/世纪~2。计算中采用的月亮潮汐加速为n=—22″.44/世纪~2。文中对解的稳定性进行了讨论。

There are a lot of records of occultation in Chinese history. In this paper, we obtained the secular acceleration of the Earth's rotation by means of a new method called "really visible time" (RVT) from ancient Chinese occultation records. Although there are the dates of observations without the moment in these records, the covered star was visible only within limiting time on the given day. We call it "RVT". For example, when an occultation in the dusk (early in a lunar month), the observation must be from the moment when the star appeared in the sky to another moment when the star set. So we can use RVT for arranging error and taking weight, and use the center of RVT as the moment of the observation. Many records can be processed together in order to obtain a comprehensive result. From 83 carefully selected records of occultation of star by the moon (186—567 A.D.), we obtained the acceleration ()=-49.7±4.2 sec/century^2 or △t=5.42×10~3 see for our weight mean epoch 423 A.D.. We adopted lunar tidal acceleration ()=-22.4″/century^2 in our computing. Stability of the result was discussed in this paper.