仪天历
Northern Song · Shi Xu
Overview
Promulgated in 1001 CE under Shi Xu and used for over twenty years.
Key data
| Item | Detail |
|---|---|
| Period of use | 1001 – 1023 CE |
| Compiler | Shi Xu |
| Year head | Jian-yin |
Development
The Yitian calendar was made by Shi Xu, promulgated in 1001 CE, replacing the Qianyuan and used until 1023.
Most Northern Song calendrists worked within the old methods with minor adjustments; so with this one.
Calendar and prognostication
Song calendrists often also held posts in prognostication, and the two ran side by side. Yet the calendar seeks the regular course of the heavens, while prognostication asks after anomalies — different matters, to be kept apart.
Compiled and arranged by Chujia Kuang.