The Inheritance From Chongzhen Lishu And The Improvement On It: About The Solar Motion, Lunar Motion And Eclipse Theories In Lixiang Kaocheng

After Western astronomy being introduced in China during late MingDynasty, Chinese scholars began to comprehend and interpret it, then tried tointegrate it with Chinese traditional astronomy. Lixiang kaocheng (ThoroughInvestigation of Astronomiccal Phenomena) is a typical work in whichWestern classical astronomical theories were sorted out and revised by MeiJuecheng and He Guozong, who were appointed by Kangxi emperor, underthe direction of Prince Rong, Yunlu and Prince Zhuang, Yunzhi. This workembodies the main achievements obtained by the Chinese scholars who hadlearned Western astronomy for decades. It also shows what they chose fromWestern astronomy, how they understood, and their value orientation betweenChinese tradition and Western learning.The current researches mainly focus on Chongzhen lishu (Books onCalendrical Astronomy of the Chongzhen Reign) and Xiyang xinfa lishu(Books on Calendrical Astronomy Based on Western New Method). However,Lixiang kaocheng hasn’t been explored comprehensively and systematically.This dissertation attempts to show the algorithm and the demonstration usedin Lixiang kaocheng, summarizes the calculation details about sun, moon,solar eclipse and lunar eclipse in Lixiang kaocheng, and analyzes what itinherited and improved from Chongzhen lishu–especially, the majorimprovements such as―diurnal inequality‖,―the four-wheel lunar motion model‖,―the modified method for the radius of the Earth’s shadow‖,―mean-quadrant of lunar orbit‖and―lunar orbit’s parallax‖is compared andanalyzed in detail. Based on strict analysis and comparison of the primarytexts, this dissertation reappraises the academic meaning and historicalposition of Lixiang kaocheng, and discusses the official astronomers’ attitudetowards Western astronomy, research level, value orientation, and theirhistorical limitations in early Qing Dynasty.This dissertation includes four chapters. Chapter One summarizes thetheory of solar motion in Lixiang kaocheng. The cosmic model in Chongzhenlishu was eccentric model, which was changed into double-wheel model inLixiang kaocheng. In addition, diurnal inequality, perigee motion model werealso improved accordingly in it. Based on the former researches, this chapterinterprets the theory of solar motion and its detail algorithm in Chongzhenlishu and Lixiang kaocheng through analyzing the primary sources.Chapter two focuses on the lunar motion theory in Lixiang kaocheng. InChongzhen lishu, the lunar motion theory, which including various lunarmotion models established by Ptolemy, by Copernicus and by Tycho, weredescribed rather ambiguously. So the theoretical models didn’t match withtheir tables, contradicting with each other. In Lixiang kaocheng, in contrast,the relevant content was edited more clear, and the structure was more logical.Moreover, the model was modified largely: Tycho’s model was changed intofour-wheel model; some texts redundant and contradictive were deleted. Meanwhile, some astronomical constants, such as the motion of intersectionof the ecliptic orbit and the lunar orbit, and the changing value of the anglebetween ecliptic orbit and lunar orbit were interpreted by astronomical models.Based on the former researches and the analysis of primary sources, thischapter tries to summarize the construction theory of lunar motion model inChongzhen lishu and Lixiang kaochen, to show the difference between themand the improvement of Lixiang kaocheng on Chongzhen lishu. It alsoevaluates Chinese official astronomers’ research level on Western astronomyand their value oriention between Chinese tradition and Western learning.Chapter three mainly analyzes the lunar eclipse theory in Lixiangkaocheng, which included the theory of the eclipse phenomenon andalgorithms of some parameters as follows: the apparent radius of the sun andthe moon, the radius of the Earth’s shadow, the maximum shadow and theshadow area in a lunar eclipse, the time and the direction in a lunar eclipse.These theories in Lixiang kaocheng were modified from the correspondingcontents in Chongzhen lishu. Lixiang kaocheng included both observingtechnique and theoretic calculation, making necessary improvement on theambiguous ones in Chongzhen lishu. However, its deficiency was that itemphasized particularly on the knowledge relevant to editing calendar; thecontents beyond this, such as the history of Western astronomy and therelevant physical knowledge, were deleted by a big margin. By analyzing theprimary sources, this chapter details the establishment and application of the geometrical model in the lunar eclipse theory, and analyzes the improvementof Lixiang kaocheng on Chongzhen lishu.Chapter four mainly analyzes the solar eclipse theory in Lixiang kaocheng.The theories of solar eclipse in Chongzhen lishu and Lixiang kaocheng bothincluded the algorithms of some parameters as follows: the maximum shadow,the shadow area, the time and the direction in a solar eclipse. In terms ofcalculation, Lixiang kaocheng improved the theory of parallax on Chongzhenlishu, including the change of the parallax and mean-quadrant from eclipticorbit system to lunar orbit system. The demonstrative approch was strictlogically and its structure was reasonable. It embodied the Chinese scholars’considerable proficiency in applying the Western geometrical model. Thedeficiency was the same as the case of lunar eclipse mentioned above:shortening the texts irrelevant to editing calendar in Chongzhen lushu.In general, Lixiang kaocheng was a work of reorganization anddevelopment which made by Chinese official scholars after learning Westernastronomy and calendar. It was more clear and systematic, which shows thatChinese scholars had mastered the practicing techniques of Western classicalastronomical model after they had been learning it for decades. However,because the model was outmoded, the work based on it was soon replaced bythe elliptic model that was more advanced.