Historical Organization
Chinese court astronomers
The Bamboo Annals describe a morning when the Sun appeared to rise twice. Modern calculations reconstruct an annular eclipse on 21 April 899 BCE.
Court observers linked celestial monitoring with calendars, ritual and government, creating records later useful to historians and astronomers.
Reconstructed eclipse paths allow researchers to compare the annal with the expected visibility from ancient Zheng.
When an ancient observation has a secure place and date, its timing can constrain how Earth's rotation has slowed over millennia.
