摘要
在《元史·历志一·授时历议》中保存有98条元代利用高表进行日影测量的有关数据。因其中有的数据最后一位是元尺的5毫(相当于0.123毫米),有人认为元代高表测景工作精度极高。本文对这些数据进行了分析和有关的计算,得到其与计算值的均方偏离为±0.1496元尺,约为3.6厘米左右。其与计算值的偏离最小者为0.0085元尺,也有0.21厘米。均比元尺的五毫差。经过分析,发现数据中有较显著的系统误差。扣除系统误差后得到元代高表测景数据与计算值的均方偏离为0.019元尺,相当于0.47厘米。这与《古观星台测景结果精度初析》一文中估计高表测号精度为5毫米左右的结论完全吻合,是元代高表测景精度的客观反映。
In Section on the Shouski Calendar of Calendar Chapter One in History of the Yuan Dynasty, there are 98 data of shadow lengths of the high gnomon in the Yuan Dynasty. Since the last digit of some of these data is found to be 0.0005 Yuan chi(a unit of length of the Yuan Dynasty equivalent to about 24.53cm), the precision of the measurement of the shadow lengths of the high gnomon in the Yuan Dynasty has been thought by some people as extremely high. By making an analysis and requisite calculation of the data, this paper finds the mean square deviation of the data and the calculation values to be about ±0.1496 Yuan chi (i.e. about 3.6 cm). The minimum deviation is found to be 0.0085 Yuan chi, which is much greater than 0.0005 Yuan chi. This shows that there are significant systematic errors in the data. After deducting these errors, the corresponding mean square deviation is ±0.019 Yuan chi (i.e. 0.47cm), which coincides with the conclusion deduced from the article On the Precision of the Measurements of Sun's Shadows Made by Ancient Chinese Observatories, and is an objective reflection of the precision of the measurements of shadow lengths of the high gnomon in the Yuan Dynasty.
出处
《自然科学史研究》
CSCD
1992年第2期151-157,共7页
Studies in The History of Natural Sciences
关键词
日影测量
高表测量
精度
元代
the Yuan Dynasty, shadow lengths of the high gnomon, precision
