An eclipse record preserves early Chinese astronomy

The Bamboo Annals describe a morning when the Sun appeared to rise twice. Modern calculations reconstruct an annular eclipse on 21 April 899 BCE.

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.

The Bur-Sagale eclipse was entered in the Assyrian eponym lists and is securely identified with 15 June 763 BCE.

The astronomical identification provides a fixed date for rulers and events recorded in Assyrian year-name lists.

Mesopotamian scribes accumulated long sequences of celestial records used to recognize cycles and interpret unusual events.