Guo Shoujing

Guo Shoujing

Guo Shoujing（1231-1316）was the greatest Chinese scientist in the Yuan Dynasty.In his childhood，he already showed unique intelligence.At the age of 14，he designeda lotus clepsydra，a water clock which had a bowl shaped like a lotus flower on the top from which water dripped.Throughout his life，he was bold in practice and innovation，and made remarkable achievements in hydraulic engineering，astronomy，mathematics and so on.

Kublai Khan entrusted Guo Shoujing with the regulation of China’s irrigation and waterways in 1271.He was then instructed to reform the calendar，which he completed by 1280.In 1281，

The Shoushi Calendar formulated by Guo Shoujing was issued nationwide.Guo calculated the length of a tropical year as 365.2425 days，or 365 days，5 hours，49 minutes and 12 seconds in today’s expression，with only a 26-second difference in accuracy from the actual length of the revolution that the earth spins round the sun，as proven by contemporary astronomers.

His efforts involved designing an observatory and sophisticated astronomical instruments that he used to observe the sun，the 28 constellations，and many unnamed stars.Guo Shoujing always attached importance to observation and tests，and spent three years designing and making 13 astronomical instruments.To complete the task，he set up 27 astronomical observation stations across the country to collect the necessary data.

hancheng

See author's posts