摘要
唐代天文学家一行在《大衍历》中,首次用行星变差来刻画行星盈缩历起点每年相对于冬至点的进动,此后的历法或者沿袭《大衍历》的做法直接给出行星变差,或者将行星变差隐含在相关算法中。本文全面考察了《大衍历》类历法中的行星变差常数及其含义,对于未直接给出行星变差的历法,则根据历法中的相关术文,重新构建了这些历法中行星盈缩历起点平均每年进动数值的表达式,并总结了行星盈缩历起点的进动规律。本文的研究结果表明,行星盈缩历起点并非行星近日点,但是由于外行星盈缩历起点黄经与其近日点黄经相差较小,因此可以将外行星盈缩历起点视为近日点。与此相应,行星变差或盈缩历起点进动并非行星近日点进动,由于各部历法中的行星变差或盈缩历起点进动值没有明显的规律可循,因此历法家很有可能已经具备了通过实测确定行星盈缩历起点的能力,而行星变差或盈缩历起点进动值应该是历法家确定行星盈缩历起点之后,配合上元积年而调整出来的数值。
The Tang dynasty astronomer Yixing(一行)was the first to use planetary biancha(变差,change difference)to describe the procession of the starting point of planetary y ingsuo li(盈缩历the table of planetary expansion-contraction difference)relative to the winter solstice point every year in the Great Expansion System(Dayan li大衍历).From then on,some systems followed the practice of the Great Expansion System and directly gave the value of the planetary biancha.For those systems that did not directly give this value,it can be calculated according to related algorithms in the systems.In this paper,we comprehensively examine the values of planetary biancha in the Great Expansion System and similar systems.For those systems that did not directly give the value of planetary biancha,we reconstruct the formula of the precession of the planetary starting point of planetary yingsuo li and summarize its rules.The discussion in this paper shows that the starting point of planetary yingsuo li is not planetary perihelion.However,since the error of the longitude of the starting point of planetary yingsuo li and the longitude of planetary perihelion is relatively small,thus for the outer planets,the starting point of planetary yingsuo li can be viewed as planetary perihelion.Accordingly,planetary biancha and the precession of the starting point of planetary yingsuo li is not the precession of planetary perihelion.Since there is no obvious rule to follow in the planetary biancha and the precession of starting point of planetary yingsuo li,it is speculated that the ancient Chinese astronomers may have mastered the ability to measure the planetary perihelion,and planetary biancha and the precession value of the starting point of planetary yingsuo li should be a value adjusted by the astronomers using the high epoch accumulated years(shangyuan jinian,上元积年)after they determined the starting point of planetary yingsuo li.
作者
唐泉
TANG Quan(The Institute for Advanced Studies in History of Science,Northwest University,Xi'an 710127,China)
出处
《自然科学史研究》
CSSCI
CSCD
北大核心
2024年第2期146-170,共25页
Studies in The History of Natural Sciences
基金
国家社科基金冷门绝学研究专项学术团队项目“中国古代历法中的‘步五星术’研究”(项目编号:20VJXT005)
国家社科基金重大项目“中国历法史”(项目编号:22&ZD221)。
关键词
行星变差
盈缩历
进动
大衍历
纪元历
planetary biancha(变差,change difference)
yingsuo li(盈缩历,the table of planetary expansion-contraction difference)
precession
Dayan li(大衍历,the Great Expansion System)
Jiyuan li(纪元历,the Era Epoch System)
