The Chongzhen calendar () or Shixian calendar () was a historical edition of the

lunisolar A lunisolar calendar is a calendar in many cultures, that combines monthly lunar cycles with the solar year. As with all calendars which divide the year into months, there is an additional requirement that the year have a whole number of months ...

Chinese calendar The traditional Chinese calendar, dating back to the Han dynasty, is a lunisolar calendar that blends solar, lunar, and other cycles for social and agricultural purposes. While modern China primarily uses the Gregorian calendar for officia ...

from 1645 to 1913. It was developed by the lead of

Xu Guangqi Xu Guangqi or Hsü Kuang-ch'i (April 24, 1562– November 8, 1633), also known by his baptismal name Paul or Paul Siu, was a Chinese agronomist, astronomer, mathematician, scholar-bureaucrat, politician, and writer during the late Ming dynasty ...

with the assistance of the Jesuit scholars

Johann Schreck Johann(es) Schreck, also Terrenz or Terrentius Constantiensis, Deng Yuhan Hanpo 鄧玉函, Deng Zhen Lohan, (1576, Bingen, Baden-Württemberg or Constance – 11 May 1630, Beijing) was a German Jesuit, missionary to China and polymath. He i ...

and

Johann Adam Schall von Bell Johann Adam Schall von Bell (1 May 1591 – 15 August 1666) was a German Jesuit, astronomer and instrument-maker. He spent most of his life as a missionary in China (where he is remembered as "Tang Ruowang") and became an adviser to the Shunz ...

from 1624 to 1644, and was dedicated to the

Chongzhen Emperor The Chongzhen Emperor (6 February 1611 – 25 April 1644), personal name Zhu Youjian, courtesy name Deyue,Wang Yuan (王源)，''Ju ye tang wen ji'' (《居業堂文集》), vol. 19. "聞之張景蔚親見烈皇帝神主題御諱字德約，行� ...

. When he died a year after it was released, it was propagated in the first year of the

Qing dynasty The Qing dynasty ( ), officially the Great Qing, was a Manchu-led Dynasties of China, imperial dynasty of China and an early modern empire in East Asia. The last imperial dynasty in Chinese history, the Qing dynasty was preceded by the ...

by the

Shunzhi Emperor The Shunzhi Emperor (15 March 1638 – 5 February 1661), also known by his temple name Emperor Shizu of Qing, personal name Fulin, was the second Emperor of China, emperor of the Qing dynasty, and the first Qing emperor to rule over China pro ...

, who changed its name to Shíxiàn calendar. This calendar is notable for systematically introducing the concepts and development of European mathematics and astronomy to China for the first time, and constituted the first major collaboration between scientists from Europe and from the Far East. Documented in more than 100 volumes of books, It offered an encyclopedic account of

Euclidean geometry Euclidean geometry is a mathematical system attributed to ancient Greek mathematics, Greek mathematician Euclid, which he described in his textbook on geometry, ''Euclid's Elements, Elements''. Euclid's approach consists in assuming a small set ...

spherical geometry 300px, A sphere with a spherical triangle on it. Spherical geometry or spherics () is the geometry of the two-dimensional surface of a sphere or the -dimensional surface of higher dimensional spheres. Long studied for its practical applicati ...

and

trigonometry Trigonometry () is a branch of mathematics concerned with relationships between angles and side lengths of triangles. In particular, the trigonometric functions relate the angles of a right triangle with ratios of its side lengths. The fiel ...

, with extensive translations and references to

Euclid's Elements The ''Elements'' ( ) is a mathematics, mathematical treatise written 300 BC by the Ancient Greek mathematics, Ancient Greek mathematician Euclid. ''Elements'' is the oldest extant large-scale deductive treatment of mathematics. Drawing on the w ...

and the works of

Nicolaus Copernicus Nicolaus Copernicus (19 February 1473 – 24 May 1543) was a Renaissance polymath who formulated a mathematical model, model of Celestial spheres#Renaissance, the universe that placed heliocentrism, the Sun rather than Earth at its cen ...

Johannes Kepler Johannes Kepler (27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, Natural philosophy, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best know ...

Galileo Galilei Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642), commonly referred to as Galileo Galilei ( , , ) or mononymously as Galileo, was an Italian astronomer, physicist and engineer, sometimes described as a poly ...

, and

Tycho Brahe Tycho Brahe ( ; ; born Tyge Ottesen Brahe, ; 14 December 154624 October 1601), generally called Tycho for short, was a Danish astronomer of the Renaissance, known for his comprehensive and unprecedentedly accurate astronomical observations. He ...

, whose

Tychonic system The Tychonic system (or Tychonian system) is a model of the universe published by Tycho Brahe in 1588, which combines what he saw as the mathematical benefits of the Copernican heliocentrism, Copernican system with the philosophical and "physic ...

was used its main theoretical basis. In addition, a comprehensive set of

mathematical tables Mathematical tables are lists of numbers showing the results of a calculation with varying arguments. Trigonometric tables were used in ancient Greece and India for applications to astronomy and celestial navigation, and continued to be widely us ...

and astronomical

ephemerides In astronomy and celestial navigation, an ephemeris (; ; , ) is a book with tables that gives the trajectory of naturally occurring astronomical objects and artificial satellites in the sky, i.e., the position (and possibly velocity) over time. ...

was included. The main changes introduced by the calendar are: * Replacement of the original "平氣法"

solar term A solar term (or ''jiéqì'', zh, t=節氣, s=节气) is any of twenty-four periods in traditional Chinese lunisolar calendars that matches a particular astronomical event or signifies some natural phenomenon. The points are spaced 15° apart ...

system (based on dividing a tropical year equally) with one based on the

ecliptic longitude In astronomy, the ecliptic coordinate system is a celestial coordinate system commonly used for representing the apparent positions, orbits, and pole orientations of Solar System objects. Because most planets (except Mercury) and many small So ...

of the sun ("定氣法"). * Placement of intercalary months changed to accommodate the changes in the solar term system. This calendar was used from the early Qing period into the early modern era, but was modified and replaced in 1914 and again in 1928, with various minor modifications since then. In 1928, it was put under the management of

Purple Mountain Observatory The Purple Mountain Observatory (), also known as Zijinshan Astronomical Observatory, is an astronomical observatory located on the Purple Mountain in the east of Nanjing. The observatory is responsible for calculating the official Chinese calen ...

(Zijinshan Astronomical Observatory), thus the present version is popularly referenced to as the Zijin calendar. All of these editions were based on modern astronomical data. In the People's Republic of China, it has been officially standardized as GB/T 33661-2017, "Calculation and Promulgation of the Chinese Calendar", issued by the

Standardization Administration of China The Standardization Administration of China (SAC; ; abbr.: ) is an external name of the State Administration for Market Regulation. Prior to 2018, it was an administrative office under the State Council to exercise administrative responsibil ...

on May 12, 2017.

References

Xu Guangqi Specific calendars 1634 establishments in Asia * , now at University of Oslo * * * * * * * * {{China-hist-stub