The Huntian theory represented a prominent cosmological perspective in ancient China. It incorporated the concept of a spherical sky, which resembled the modern understanding of astronomy. Influenced by this theory, the Hunyi emerged as an astronomical measurement instrument. As a pivotal tool in ancient Chinese astronomy, advancements in the manufacturing techniques of the Hunyi were intricately tied to the milestones achieved in Chinese astronomical endeavors.
The Northern Song Dynasty (960-1127) marked a critical period for traditional Chinese astronomy. During the early Song, astronomer Han Xianfu, leveraging the groundwork laid by his predecessors, successfully constructed two Hunyis. His endeavors played a crucial role in revitalizing and restructuring Song astronomy following the disruptions caused by war.
During the mid-Northern Song period, astronomers such as Zhou Cong, Shen Kuo and Su Song contributed to the creation of four additional Hunyis. Through relentless structural enhancements, the design and functionality of the Hunyi underwent substantial improvements. Notably, the Water-powered Astronomical Clock Tower stands as the pinnacle of ancient Chinese astronomical instrument manufacturing.
Following the conquest of the Northern Song Dynasty by the Jurchen, the technology for producing Hunyi not only persevered but also garnered fresh opportunities for development. Among the six Hunyis crafted during the Northern Song period, four were transferred to northern China under the Jin regime, while one was carried south by the successors of the Song Dynasty. Each of these instruments continued to play a vital role, substantially contributing to the advancement and progress of both the Jin and Southern Song’s astronomy.

Prof Qiu Jingjia

The Chinese had a tradition of promulgating new calendars when establishing a new dynasty, a practice that the Mongols inherited as well when they established their state in the Far East. As the Mongol Empire rapidly expanded, the time differences between the east and west became increasingly evident. This discrepancy was reflected in astronomy, where the same astronomical phenomena were observed to occur at different times in the east and west. Consequently, the calendar established in China could not be used in Central Asia. To address this issue, Yelü Chucai proposed the concept of “licha,” specifically using a coefficient to correct the time differences in the east-west direction.
Two opposing viewpoints have emerged: one suggesting it was a derivative from the West, and the other advocating it was a spontaneous, indigenous product. Examining previous perspectives reveals that the main point of contention is whether “li cha” is related to geographical longitude. This issue is directly connected to the coefficient used in “licha.” The calculation formula for this coefficient shows that it is influenced by the distance between Samarkand and China. Therefore, earlier discussions have primarily focused on the distance between Samarkand and China.
This article reviews the process of calculating the “licha” coefficient, with a particular focus on why Yelü Chucai overestimated the distance between Samarkand and China. Based on these discussions, it is necessary to conclude that “licha” is unlikely to have originated from traditional Chinese astronomy and is instead closely related to Arab astronomy.

Prof Chuanyi Lyu
Hebei University

Ferdinand Verbiest designed eight astronomical instruments between 1669-1673. And he published the Xinzhi Lingtai Yixiang Zhi (<新制靈台儀象志>) in 1673, which is a book that details the structure, use and supporting data of the instruments . There are series of star catalogues which contained the position of more than 1800 stars in it. This study research into the Verbiest’s star catalogues. Through the comparison of corresponding data in star catalogues and position information extracted from the star maps, we found: Jesuits observed stars anew on the basis of western star catalogue or star map, and they were modifying the data all the time; A star catalogue contained about 500 stars is not published at the end of Ming dynasty, but it can be traced in the star maps. Verbiest publish the catalogue in his book anew; The data sources of Verbiest’ s the star catalogue is discussed in this study.

Since the introduction of Western science into China, the
latitude and longitude positioning system gradually spread and exerted influence. In the Qing Dynasty, the main sources of latitude and longitude positioning data were: first, the publication of latitude and longitude data by the imperial astronomical and calendrical institutions; second, the calculations made by mathematicians based on previous data; third, the supplementation of latitude and longitude data through field surveys organized by local governments. This paper uses Qing Dynasty maps, local gazetteers, and almanacs as source clues, focusing on the recorded gnomon tables and latitude and longitude values. It emphasizes the generation and updating of latitude and longitude data for the capital, provincial capitals, and several key cities, discussing the technical aspects of data generation and the reasons for changes from the perspectives of the history of science and the social history of Knowledge.