Astronomical Almanacs (17th Century)

Timeline

1. 1671–1674Imperial Astronomical Bureau, Beijing · ChinaAfter the calendar controversy (the Calendar Case) was overturned in 1669, Ferdinand Verbiest was appointed deputy director of the Imperial Astronomical Bureau and oversaw the recasting of six large bronze astronomical instruments at the Beijing Observatory. In 1674 he published the Lingtai Yixiang Zhi (Records of the Astronomical Instruments of the Imperial Observatory, 16 juan), illustrating the structure and use of the new instruments with text and images, and refining the numerical tables of the Shixian calendar. Tycho Brahe's system and Western spherical trigonometry were fully integrated into the Qing official almanac, markedly improving its computational accuracy.
2. 1672–1678Paris Observatory · FranceGiovanni Domenico Cassini (Cassini I) directed the Paris Observatory, systematically observing Jupiter's satellites with large telescopes and calculating their orbital periods. In 1672 he collaborated with Jean Richer to observe Mars from Cayenne in French Guiana, making the first precise determination of the Earth–Sun distance (on the order of 140 million km). This greatly improved the accuracy of planetary position predictions and provided an observational basis for the almanac data in the Connaissance des Temps.
3. 1679–1680Paris · FranceIn 1679 the French Royal Academy, with support from the Paris Observatory, founded the Connaissance des Temps, edited by Jean Picard. It published annual tables of the positions of the Sun, Moon, planets, and satellites for navigation and geodesy. It was Europe's first official astronomical almanac continuously published by a national scientific institution, marking a structural shift from private scholarly computation to a national standard data service. It continues to be published today and is one of the oldest continuously published astronomical almanacs in the world.