《授时历》历元时刻的获取  

The Acquirement of the Epoch Time of Chinese Ancient Calendar of Shoushi Li

作　　者：李勇[1] 

机构地区：[1]中国科学院国家天文台,北京100012

出　　处：《天文学报》2013年第6期569-580,共12页Acta Astronomica Sinica

基　　金：国家自然科学基金项目(10973022)资助

摘　　要：考察了《授时历议》所给出的98次日影中天观测数据,指出其观测的标准误差为4.06′.归纳并推导了古代通过三日日影中天观测数据以确定节气时刻的公式,指出它只是一种近似计算.依古法求解了至元十四年冬至时刻和至元十五、十六年的二至时刻,其与现代天文计算的标准偏差分别为38.13 min(至元十四年冬至)、43.91 min(至元十五年夏至)、38.03 min(至元十五年冬至)、34.80 min(至元十六年夏至)和23.58 min(至元十六年冬至).确认《授时历》的初始历元时刻(即气应)系由实测推导出的节气时刻叠加数个半年长而得.采用现代天文历算方法计算出1280年冬至前后400 d逐日太阳中天影长数据,对古法测算1280年冬至时刻的精度进行了评估.The data of solar shadow lengths from 98 meridian observations as recorded in Shoushi Liyi are investigated in this paper. Shoushi Liyi is one thesis to discuss and review the strongpoint of the calendar of Shou.shi Li in Yuan dynasty （1271 1368）. It points out that the standard error of these shadow observations is only 4.06＇. The ancient formula fl＇om three days＇ meridian observations of the solar shadows to obtain the time of solar term is proved and recovered, but it is only a kind of approximate calculation, not accurate enough. And according to this method and these solar shadow lengths, the winter solstice in 1277 is derived, the same as two solstices of 1278, and 1279, and their standard deviations are 38.13 rain （winter solstice in 1277）, 43.91 rain （summer solstice in 1278）, 38.03 min （winter sol- stice in 1278）, 34.80 rain （summer solstice i~） 1279）, and 23.58 rain （winter solstice in 1279）, respectively. The value of the epoch time of Shoushi Li obtained directly from the shadow observation （in Chinese Qiying means the time of winter solstice in 1280） is confirmed and directly deduced fl＇om the time of solstices, added by several half-tropical-year lengths. By using modern astronomical method, the solar shadow length every day within 400 days to winter solstice in 1280 when the sun transited in 1280 is obtained with the ancient method. is calculated, and then the time of this solstice Their accuracies are obtained and reviewed.

关 键 词：天文学史和哲学 历书 

分 类 号：P195[天文地球—天文学]