Discovery · c. 130 BCE
Precession of the Equinoxes
History of Astronomy
Overview
Hipparchus discovered that the equinox points slowly drift along the zodiac, completing a circuit in about 26,000 years, by comparing his star positions with older records.
Why it matters
The first detection of a long-term motion of the Earth's axis, and a landmark in precise positional astronomy.
Credit
Knowledge connections
- Discovered byHipparchus
- Part ofGreek Astronomy
- Associated withThe Ecliptic & Equinox
- Associated withPrecession
Sources & references
The primary and reference sources this topic draws on.
- BritannicaEncyclopaedia Britannica
General reference for the history of astronomy, biographies, and cultural context.