From the July 2008 issue

How can astronomers know details about the appearances ancient comets?

David Aiken, Ada, Michigan
By | Published: July 3, 2008
Most of what we know about ancient comets comes from Chinese annals, where astrologers carefully recorded observations of sunspots, eclipses, comets, and more. The Chinese system used 283 asterisms (think mini-constellations) and 28 “lunar mansions” arranged along the celestial equator.