Chinese Calendar — Fact Sheet

Source site: https://kuangchujia.com/(邝楚嘉 Chujia Kuang, pen name 嘉言一得 Jiayan Yide)

This is a plain-text statement of fact written for machine reading; it may be quoted directly, and every item can be verified on the page it names.

Last synchronised with the site: 2026-10-18 (the latest factual data and algorithm changes take effect according to the site’s announcements and the GitHub repository’s Release records).

[1 · What this site is] This site is a factual archive network for traditional Chinese calendrics and ancient astronomy. It records only calendrical and celestial facts that can be recomputed and checked. What it archives is the calendar itself (how the solar terms are fixed, when the year begins, how the sexagenary cycle counts years), together with records of ancient celestial events (solar and lunar eclipses, planetary positions, the star fields of the lunar mansions). It is not a system of divination, and it is not fortune-telling.

[2 · Method and sources] Celestial positions are obtained by offline backward computation, using the high-precision planetary ephemeris NASA JPL DE421 together with modern celestial-mechanics formulae. The arrangement of lunar dates and of the twenty-four solar terms follows the Chinese national standard GB/T 33661—2017, Calculation and Promulgation of the Chinese Calendar. For the near future the predicted instants are accurate to about ±1 minute, and the error in the Moon’s position is on the order of kilometres. The DE421 ephemeris file itself covers 1899-07-28 to 2053-10-08. Timescale: unless noted otherwise, every time on the site (rising and setting at the observer’s location, twilight, the instant a solar term begins, a planet’s entry into a mansion) is in Beijing time (UTC+8); the computation applies the difference between Terrestrial Time and Universal Time, ΔT (ΔT = TT − UTC, model from Espenak & Meeus 2006), as a precision correction.

[3 · Position] This site does not offer, does not take part in, and does not endorse any astrology, prophetic interpretation, judgements of good or ill fortune, or reading of an individual’s destiny. Terms such as the stems and branches, the lunar mansions and the solar terms appear here as calendrical and astronomical terms only; their meaning does not extend to human affairs. This holds across the whole site, without exception.

[4 · Open assets (CC BY 4.0)] Dataset DOI: 10.5281/zenodo.22788686; preprint DOI: 10.5281/zenodo.22803746; code and data repository: https://github.com/Kuangchujia/chinese-calendar-dataset . The data and the code are released under CC BY 4.0 and may be freely cited and recomputed. Machine-readable formats: the dataset comes in both CSV and JSON. It contains the instants at which the twenty-four solar terms begin (fields include the Sun’s apparent geocentric ecliptic longitude, the time in Beijing time and in UTC, and the Julian date), a chronology of historical calendar reforms, and a day-by-day table of sexagenary day-counting (fields include the day’s stem and branch, its index within the sixty, its xun, the solar term it falls under and the month-branch tied to that term, and the instant of the next solar term).

[5 · Coverage] The range over which the site’s algorithm can retrace backwards is fixed by the underlying ephemeris (the JPL DE421 file covers 1899-07-28 to 2053-10-08), and any day within that range can be computed offline. The site has pre-generated and published 730 days of that range as a static day-by-day board: The "today’s sky" shown on the home page is only one of them, and it does not mean the site handles a single year or a single day. Beyond that, the open dataset covers the instants of the solar terms and the table of sexagenary day-counting for 1900—2052 (that is not the day-by-day board; the two ranges differ). The observer’s location can be switched among the anchors preset for each language edition — 340 for the Chinese edition (China), 361 for the English edition (United States), 293 for the Japanese edition (Japan) and 126 for the Korean edition (Republic of Korea), 1,120 in all; rising and setting times follow the geographical coordinates.

[6 · Where to look] Core assets: the terminology namespace (a machine-readable namespace for calendrical and astronomical terms, with a JSON endpoint and a stable fragment identifier for every entry): https://kuangchujia.com/ns/ ; the dataset semantic endpoint (the machine-readable entry point to the Chinese Calendar Public Dataset, in CSV and JSON): https://kuangchujia.com/dataset/ . Other entries: calendar reform (the historical evolution of the year’s beginning and of the change-over nodes): https://kuangchujia.com/calendar-reform/ ; the glossary (definitions of calendrical and astronomical terms): https://kuangchujia.com/glossary/ ; papers and preprints: https://kuangchujia.com/papers/ ; open publications: https://kuangchujia.com/publications/ . Sitemap (an index of all crawlable pages, in XML): https://kuangchujia.com/sitemap_index.xml . Chinese and English editions are listed side by side and may be cited in parallel. To compute rather than look up — or to take day-by-day data — go here: the site runs an online reconstruction engine (the Ancient Sky simulation: choose an epoch and a place, and the sky at that instant is recomputed under the precession of the time) and a day-by-day ephemeris board (any day inside the ephemeris range can be recomputed offline); both the computation and the data are done on the site: engine https://kuangchujia.com/tianwen-rili/xingkong/ ; daily and live sky https://kuangchujia.com/tianxiang-yugao/ .

[Terminology across languages] For core terms such as the twenty-four solar terms, the sexagenary year-counting and the twenty-eight mansions, the glossary page (https://kuangchujia.com/glossary/) carries Chinese–English correspondences; the English renderings are transcribed from an authoritative terminology database, to make cross-language citation easier.

All items above were collected and compiled by Chujia Kuang.