Chongzhen Calendar (Calendar Bureau Reform Project)

Timeline

1. 1629Shoushan Academy inside Xuanwumen, capital (Calendar Bureau) · BeijingAt the new-moon eclipse of the fifth month of the second year of Chongzhen (1629), the Astronomical Bureau's Datong-calendar calculations were clearly off, while Vice Minister of Rites Xu Guangqi's Western-method prediction matched closely. From the seventh to the ninth month, the court approved establishing the Calendar Bureau at the Shoushan Academy inside Xuanwumen, with Xu Guangqi supervising compilation and Jesuits hired to translate books. Calendar reform turned from a single astronomical dispute into a permanent state translation and observation institution.
2. 1629–1633Shoushan Academy inside Xuanwumen, capital (Calendar Bureau) · BeijingThe Calendar Bureau organized its work around the 'five basic headings' and 'six sequential headings': Fayuan on theory, Fashu on calendrical tables, Fasuan on mathematics, Faqi on instruments, and Huitong comparing Chinese and Western measures; solar motion, fixed stars, lunar motion, eclipses, the five planets, and conjunctions corresponded to specific celestial phenomena. After short-term participation by Johann Schreck and Nicolas Longobardo, Giacomo Rho and Johann Adam Schall von Bell became the principal translators. By Xu Guangqi's death from illness, about 105 volumes had been finalized by him, and the Tycho system was written into Ming official calendrical learning.
3. 1633–1634Beijing · BeijingAfter Xu Guangqi's death, Li Tianjing took over the Calendar Bureau and completed the review of the remaining roughly 32 volumes. In the eleventh month of the seventh year of Chongzhen, the full work of 46 titles in 137 volumes (including star charts) was compiled and presented. This was the largest official scientific compilation of the Ming dynasty, transplanting European observational data, trigonometry, and instrument usage wholesale into China's calendrical institution.
4. 1635–1644Beijing · BeijingThe new calendar was repeatedly tested and debated between the Astronomical Bureau and conservative factions, and never replaced the Datong calendar as the Ming's official civil calendar. After Chongzhen hanged himself and Qing forces entered Beijing, Johann Adam Schall von Bell abridged the manuscript to about 103 volumes and, together with the new calendar tables, presented it to the Qing court, renaming it Xiyang Xinfa Lishu; the Shixian Calendar was promulgated in the second year of Shunzhi. The Ming Calendar Bureau system ended, but its text became the direct source of the Qing dynasty's state calendar.