明清之际天文测量与天文历法常数系统的改进

Western astronomy was introduced to China in the late Ming dynasty. Xu Guangqi led the Chongzhen Calendar Reform in 1630s and produced a comprehensive astronomical treatise titled Chongzhen lishu. Chinese astronomy embarked on a westernization process, which was continued in the early Qing. Two major astronomical treatises were completed under the imperial sponsorship: the Lixiang kaocheng of 1722 and the Lixiang kaocheng houbian of 1742. While introducing western theories and observational data, original measurements were also made in China and were incorporated into the computation and theorizing of Chinese mathematical astronomy. In this project we study the how observational data was reflected in astronomical constants. We focus on three questions: 1) The relations between measurements of longitude and latitude with calendrical computation. How were longitude and latitude embodied in the calendar? What were the accuracies of measurements and values of the astronomical constants? 2) The measurement and determination of astronomical constants that are related to the cosmological models used in the calendrical calculation. We will focus on planetary motions. 3) The circulation between China and West of observational data, including historical ones, such as gnomon shadow lengths, solar and lunar eclipses, and its impact on astronomy. In this study we will focus on the gnomon shadow measurements and the study of the secular change of the ecliptic obliquity.

明末之际西方天文学传入中国，徐光启等人引进“西法”，进行历法改革，中国天文学从此进入了中西汇通的近代化进程。明清之际官方修订的几部历法，如《崇祯历书》、《历象考成》和《历象考成后编》, 还有民间修订的历法，如王锡阐的《晓庵新法》、《五星行度解》等，是这一时期中国天文学的重要成果。本项目考察明清之际的天文测量，分析天文历法的常数系统，探讨这一时期天文测量与历法理论推算的关系。主要研究三方面的问题：1）地球经纬度测量对历法计算的影响。地理经纬度测量的方法和精度如何？经纬度概念如何体现在历法推算之中？测量精度如何影响了历法推算的精度？2）与宇宙理论模型相关的历法常数的测量和确定。重点研究与五星运动模型相关的天文常数。3）中西方测量数据的交流和对天文学的影响。清代及历史上的文观测数据，如表影测量、日月食观测等数据， 如何影响中西方天文学？本项目主要考虑表影测量与黄赤交角变化的问题。

本项目从三个方面进行了研究： .1. 地球经纬度测量对历法计算的影响。经纬度的引入改进了日月食的预测，为明清历法改革引入西法起了决定性的作用。同时探讨了大地经度测量与天文历法计算的关系。指导完成博士论文1篇，发表论文1篇。 .2. 与宇宙理论模型相关的历法常数的测量和确定。研究了《历象考成》的太阳运动模型，指出清康熙朝的改历是如何在西方天文学知识的基础上提出了术阳运动的双本轮模型。研究成果发表在JHA （SCI期刊）上。 .3. 中西方测量数据的交流和对天文学的影响。指导完成硕士论文2篇，一是苗圆柯的《16、17世纪的彗星观测和争论》，二是柳紫陌的《不完整的传播：日心说在中国》。另在JHA （SCI期刊）发表关于超新星记录的论文1篇。.此项研究对清代历法模型和历法常数有了更精楚的认识，对明清以来中西天文学的汇通和中国天文学的现代化进程有了更深刻的认识。