Xu Ang Explained

Xu Ang was a Chinese court astronomer of the Tang dynasty.

Shortly after Emperor Xianzong's ascension in 805, he created the Guanxiang Calendar (Chinese: 觀象曆), which was used throughout Emperor Xianzong's reign beginning in 807.^[1]

In 822, during Emperor Muzong's reign,^[1] he created the Xuanming calendar,^[2] one of the most influential calendars in the world. It was used for 71 years in China, for at least 475 years in Korea, and for 823 years in Japan.^[3]

Notes and References

1. Book: Chen Jiujin ({{lang|zh-hans|陈久金}}). 中国古代天文学家. Astronomers of Ancient China. Chen. 徐昂. Xu Ang. zh. 272–280. 2008. 978-7-5046-4839-6. China Science and Technology Press.
2. Book: Qu Anjing. History of Oriental Astronomy: Proceedings of the Joint Discussion-17 at the 23rd General Assembly of the International Astronomical Union, Organised by the Commission 41 (History of Astronomy), Held in Kyoto, August 25–26, 1997 . Ansari. S. M. Razaullah. S. M. Razaullah Ansari. 220. Springer Science+Business Media. Revisiting an Eighth-Century Chinese Table of Tangents. 2002. 978-90-481-6033-4.
3. Analysis of Solar and Lunar Motions in the Seonmyeong Calendar. Lee. Ki-Won. Journal of Astronomy and Space Sciences. 2019. 87. 36. 2. 18 July 2021.