The Solar And Lunar Positions Of Eclipse Records And The Algorithm Of Their Positions In Ancient China

The computation of the positions of the Sun and Moon plays an important role in various algorithms of ancient Chinese calendars. There is information of solar and lunar positions in many eclipse records in ancient China. Research on such information and the algorithms about the positions in calendars is useful for understanding those ancient records of eclipses correctly and grasping their real origins. Such records before the Qing dynasty and related algorithms are discussed in the first part of this thesis. In the second part of this thesis, the author analyzes the official and local records of the solar eclipses of the Qing dynasty, including records with solar positions and related algorithms. The main researches and achievements of this thesis are as follows:Based on the study of the original materials, the algorithms of solar positions of the new moon and midnight of the new moon in ancient Chinese calendars are analyzed, which can be classed basically by era as three kinds: uniform motion of the Sun and the Moon, non-uniform lunar motion and non-uniform motion of the Sun and the Moon. Equation of center brought by the elliptic motion is considered mainly in non-uniform correction of solar and lunar motion in ancient Chinese calendars.The measurements of solar positions in solar eclipse records in ancient China, which are seldom studied before, are analyzed. Such records in official historical documents concentrated in those of the Western Han, Eastern Han, Tang, Song and Qing dynasties. The solar positions in these records were obviously calculated beforehand or afterworlds. Local chronicles of the Ming and Qing traced back the past ones. An analysis by modern computation shows, the records of the Han Dynasties were computed according to uniform solar motion, while for those of the Tang Dynasty, an annual correction was added. The origins of records of the Western Han, Eastern Han and Tang dynasties are discussed by comparing with results calculated according to ancient calendars.The arithmetic about lunar positions in lunar eclipse ancient calendars is discussed in this thesis. This algorithm first appeared in Jiaohui(交会) of Chongxuan Calendar, which was written by Biangang(边冈) in the Tang dynasty. The computational method in majority calendars remains the same since Yingtian Calendar of the Song dynasty.The lunar positions seen in the records of lunar eclipse in ancient China are analyzed. Such a study has not been done. It comes to the conclusion that original and independent records only existed basically in the official historical documents. Such records concentrated in those of the Northern Wei, Song and Qing dynasties. Through comparing with the results by modern computation, the error rates are given to those dynasties respectively. The lunar positions in eclipse records of the Qing Dynasty came apparently from forecast, while such information in records of previous dynasties should come from practical observations. The accuracy of the forecast lunar position got improved after 1740s and the main reason for this is discussed in this thesis. Local chronicles edited in the Ming and Qing contains some lunar eclipse records with lunar positions. These eclipse records mainly are of the Song and Ming Dynasties. Overall computation with modern astronomy reveals that the error rate is 21% for the Song and 6% for the Ming. Compared with the local records of solar eclipse, the reliability of local records of lunar eclipse is higher (according to a statistics to solar eclipse in local chronicles, the error rate is 34% for the Tang, 92% for the Ming and more than 50% for other dynasties).Through overall computation with modern method, official records of solar eclipse in the Qing Dynasty are analyzed and discussed. The detail data of eclipses recorded in Qingshigao, Qingshilu and Qingchao Wenxian Tongkao are proven to be forecast. The majority of the solar eclipse took place in the Qing Dynasty are documents in the official records (of solar eclipse). The predicted eclipse time got improved by about 5 minutes after 1735. The reasons for improvement and deterioration of accuracy of the predicted mansions of solar eclipses are analyzed. The method for computing azimuth of solar eclipse in Xiyang Xinfa Lishu was different from that in Lixiang Kaocheng - Yixiang Kaocheng Houbian. The latter was greatly improved.The local records of solar eclipse in the Qing dynasty are analyzed and researched in this thesis. Those records can be divided into two categories. One category includes 546 records that are identical with official historical records and have few mistakes. There error rate is only 2% mistakes. The majority of such records should be transcribed from official history. The other category is independent local records whose dates or detail are different from those in official records. Their error rate of is as high as 54%. There are 311 records of such records are regarded as"completely independent"because no eclipse has been recorded on those days in official history and very few of them are correct. The majority of dates of them might be transcribed wrong. It is extremely like that few, if any, were real independent local observation. In addition, rich local records of total or close to total solar eclipse are analyzed.