Jesuit Astronomy in China: Events, Sources and Historical Consequences

Diterbitkan oleh Anthony
pada November 11, 2026

See how Chinese officials and Jesuit astronomers revised the imperial calendar, tested predictions at court, and equipped Beijing’s observatory in the 1600s.

Quick Answer: What Did Jesuit Astronomers Do in China?

In seventeenth-century China, Jesuit astronomers worked with Chinese officials and specialists to revise the imperial calendar. Xu Guangqi (徐光启, Xú Guāngqǐ) supervised the late Ming reform. Under the Qing, Johann Adam Schall von Bell (汤若望, Tāng Ruòwàng) helped introduce the new methods at the Imperial Astronomical Bureau (钦天监, Qīntiānjiān). ^[1][3][4]

1629: Competing predictions of a solar eclipse helped prompt a Ming calendar project.
1640s: The Qing court adopted a revised system based on the Ming work.
1668: Ferdinand Verbiest (南怀仁, Nán Huáirén) defended the methods in a court test of the length of a shadow. ^[2][3][5][6]

The new calculations entered a Chinese lunisolar calendar tradition and an observatory that already had its own instruments. ^[3][4][7]

From Ming eclipse predictions to the Qing shadow trial and new observatory instruments.

An astronomer could turn a court dispute into a measurement by saying how long a shadow would be at noon. That gave officials a result they could check, and the outcome could determine who ran the calendar office.

Why the Ming Court Reconsidered the Calendar

The calendar issued under imperial authority coordinated timekeeping across the empire. The court needed calculations for the starts of months, the timing of solar terms and the prediction of eclipses. At the end of the Ming dynasty, officials could compare results from established Chinese, Islamic and recently introduced European methods. ^[2][3][4]

Xu Guangqi worked with Matteo Ricci on a Chinese translation of Euclidean geometry before he oversaw the calendar project. On June 21, 1629, observers had a chance to compare forecasts of a solar eclipse that appeared partial in Beijing. A modern comparison of the reported predictions with a reconstructed eclipse finds the Jesuit forecast better overall, with errors of its own. The result helped Xu make the case for a larger reform. ^[1][2][3]

Xu supervised the compilation of the Chongzhen lishu (崇祯历书, Chóngzhēn Lìshū), a collection of astronomical texts and tables. Jesuits including Schall and Giacomo Rho worked on the project. After Xu died in 1633, Li Tianjing (李天经, Lǐ Tiānjīng) continued the work and oversaw comparisons among the rival methods. Its texts and tables could be consulted again each year when making a new calendar. ^[1][3][4]

How the Qing Adopted the New Methods

The fall of the Ming in 1644 changed the patron of the work. Schall brought the Ming compilation to the new Qing dynasty court. The compendium was recopied for the Qing in 1645 under a new title. The calculations formed the basis of the system now commonly called the Shixian calendar (时宪历, Shíxiàn Lì). The Qing adopted the new methods while retaining lunar months and solar terms. ^[3][4]

The court’s choice gave Schall authority in the bureau and placed missionaries in an office responsible for more than calculation. Choosing dates for imperial occasions involved political and ritual responsibilities. When opponents challenged the bureau’s work, they could question both the accuracy of its astronomy and the fitness of the people entrusted with it. ^[3][4][5]

Why the Calendar Case Led to a Shadow Test

The Calendar Case (历狱, Lìyù) began in 1664 when the scholar Yang Guangxian (杨光先, Yáng Guāngxiān) brought charges against Schall and his colleagues. His accusations included the choice of an inauspicious date for an imperial burial. The authorities imprisoned Jesuits and their Chinese colleagues. The missionaries’ sentences were later commuted, while five Chinese astronomers were executed. ^[3][5]

In late 1668 the Kangxi Emperor called for a prediction that officials could check. Verbiest proposed comparing how long a gnomon’s shadow would be. The gnomon in this trial was an upright marker. Its shadow shortened or lengthened as the Sun’s apparent position changed. Each side could calculate a length for the same instrument and moment, then compare the forecast with the observed length. ^[5][6]

The test was repeated at noon on three successive days, and Verbiest’s results persuaded the court. Further tests and decisions followed. By 1669, Verbiest had gained responsibility for the bureau’s astronomy. The length of the shadow answered a narrow astronomical question. The court used that result to decide who would supervise a much wider body of work. ^[5][6]

What the Observatory and Its Books Preserve

The Beijing Ancient Observatory already had a history of astronomical instruments under the Ming. In the early Kangxi period, Verbiest and his collaborators added six instruments, including armillary spheres, a quadrant, a sextant and a celestial globe. A quadrant, for example, could be used to measure an object’s angle above the horizon. ^[7][9]

The Chinese treatise on the new instruments has a preface dated 1674. A surviving copy helps identify the people behind the text. A catalogue of one copy credits Liu Yunde for taking down the text and Sun Youben and Xu Hu for further work on it. The treatise sets out why Verbiest wanted calibrated instruments. The credits name contributors who can be hard to see in accounts centered on Jesuit correspondence. ^[8][9]

FAQs About Jesuit Astronomy in China

Did the Qing adopt the Gregorian calendar in the 1640s?

The early Qing kept a Chinese lunisolar calendar. It adopted new astronomical methods to determine calendar dates while retaining lunar months and solar terms. ^[3][4]

Was the 1668 test a prediction of a solar eclipse?

The test that December compared predictions of the shadow cast by a fixed upright marker. The solar eclipse comparison belonged to the earlier Ming reform in 1629. ^[2][6]

Do any of the instruments survive?

Yes. The Beijing Ancient Observatory preserves Qing instruments on its tower, including those associated with Verbiest’s project. The observatory’s collection also includes instruments added after his lifetime. ^[7]