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Gnomon shadow lengths recorded in the Zhoubi Suanjing: the earliest meridian observations in China?
Li, Yong1; Sun, Xiao-Chun1,2
2009-12-01
Source PublicationRESEARCH IN ASTRONOMY AND ASTROPHYSICS
Volume9Issue:12Pages:1377-1386
AbstractThe Zhoubi Suanjing, one of the most important ancient Chinese books on mathematical astronomy, was compiled about 100 BC in the Western Han dynasty (BC 206 - AD 23). We study the gnomon shadow lengths for the 24 solar terms as recorded in the book. Special attention is paid to the so-called law of 'cun qian li', which says the shadow length of a gnomon of 8 chi (about 1.96 m) high will increase (or decrease) 1 can (1/10chi) for every 1000 li (roughly 400km) the gnomon moves northward (or southward). From these data, one can derive the time and location of the observations. The results, however, do not fit historical facts. We suggest that compilers of the Zhoubi Suanjing must have modified the original data according to the law of 'cun qian li'. Through reversing the situation, we recovered the original data, our analysis of which reveals the best possible observation time as 564 BC and the location of observation as 35.78 degrees N latitude. We conclude that this must be the earliest records of solar meridian observations in China. In the meantime, we give the errors of solar altitudes for the 24 solar terms. The average deviation is 5.22 degrees, and the mean absolute deviation is 5.52 degrees, signifying the accuracy of astronomical calculations from that time.
KeywordHistory And Philosophy Of Astronomy Solar Meridian Observation Accuracy Solar-terrestrial Relations Methods: Statistical
Indexed BySCI
Language英语
WOS IDWOS:000272967100010
Citation statistics
Cited Times:1[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/8126
Collection应用天文研究部
Affiliation1.Chinese Acad Sci, Natl Astron Observ, Beijing 100012, Peoples R China
2.Chinese Acad Sci, Inst Hist Nat Sci, Beijing 100010, Peoples R China
Recommended Citation
GB/T 7714
Li, Yong,Sun, Xiao-Chun. Gnomon shadow lengths recorded in the Zhoubi Suanjing: the earliest meridian observations in China?[J]. RESEARCH IN ASTRONOMY AND ASTROPHYSICS,2009,9(12):1377-1386.
APA Li, Yong,&Sun, Xiao-Chun.(2009).Gnomon shadow lengths recorded in the Zhoubi Suanjing: the earliest meridian observations in China?.RESEARCH IN ASTRONOMY AND ASTROPHYSICS,9(12),1377-1386.
MLA Li, Yong,et al."Gnomon shadow lengths recorded in the Zhoubi Suanjing: the earliest meridian observations in China?".RESEARCH IN ASTRONOMY AND ASTROPHYSICS 9.12(2009):1377-1386.
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