Editing Chinese calendar (section)

==== Ming and Qing Shíxiàn calendar ====
{{Main|Chongzhen calendar}}
{{anchor|Shíxiàn calendar|Shixian calendar|Chongzhen calendar}}
From 1645 to 1913 the ''{{tlit|zh|pinyin|Shíxiàn}}'' or ''Chongzhen calendar'' was developed. During the late [[Ming dynasty]], the Chinese Emperor appointed [[Xu Guangqi]] in 1629 to be the leader of the [[Chongzhen calendar|Shixian calendar]] reform. Assisted by Jesuits, he translated Western astronomical works and introduced new concepts, such as those of [[Nicolaus Copernicus]], [[Johannes Kepler]], [[Galileo Galilei]], and [[Tycho Brahe]]; however, the new calendar was not released before the end of the dynasty. 

In the early [[Qing dynasty]], [[Johann Adam Schall von Bell]] submitted the calendar which was edited by the lead of [[Xu Guangqi]] to the [[Shunzhi Emperor]].<ref>{{cite journal |last1=Stone |first1=Richard |title=Scientists Fete China's Supreme Polymath |journal=Science |date=2 November 2007 |volume=318 |issue=5851 |pages=733 |doi=10.1126/science.318.5851.733 |pmid=17975042 |s2cid=162156995 |doi-access=free }}</ref> 
The Qing government issued it as the ''{{tlit|zh|pinyin|Shíxiàn}} (seasonal) calendar''. In this calendar, the [[solar term]]s are 15° each along the [[ecliptic]] and it can be used as a [[solar calendar]]. However, the length of the climate term near the [[Apsis|perihelion]] is less than 30 days and there may be two mid-climate terms. The {{tlit|zh|pinyin|Shíxiàn}} calendar changed the mid-climate-term rule to "decide the month in sequence, except the intercalary month."<ref>{{Cite web |script-title=zh:本世纪仅有4次！闰二月为何少见？-新华网 |url=http://www.news.cn/tech/2023-03/21/c_1129450471.htm |access-date=2023-05-02 |website=www.news.cn |archive-date=2 May 2023 |archive-url=https://web.archive.org/web/20230502045811/http://www.news.cn/tech/2023-03/21/c_1129450471.htm |url-status=live }}</ref> 

The present "traditional calendar" follows the Shíxiàn calendar, except:
# The baseline is Chinese Standard Time, rather than Beijing local time.
# Modern astronomical data, rather than mathematical calculations, is used.