Case file · Cosmic event
The Qin comet of 240 BCE (Halley)
The Shiji and the Qin annals record a 'broom star' seen first in the east and then in the north and west in 240 BCE, the earliest sure sighting of Halley's Comet.
240 BCE · 34.33, 108.71 · status: official
The account
Chinese court astronomers went on to log almost every return of the comet. Their records, matched against orbital calculations, let modern astronomers trace Halley's path back more than two thousand years.