Reference frame
The Ecliptic & Equinox
The plane of the Earth's orbit around the Sun, and the equinox where it crosses the celestial equator. For millennia the equinox was the origin of celestial coordinates — but because it slowly precesses, modern frames are fixed to the stars instead.
Bodies, frames & concepts
Across celestial mechanics
Knowledge connections
- Associated withPrecession of the Equinoxes
- Associated withThe International Celestial Reference System
- Associated withThe B1950 Epoch
- Associated withThe Ecliptic Coordinate System
- Associated withPrecession
Sources
The primary and reference sources this topic draws on.
- IAUInternational Astronomical Union
Official naming, definitions, constellation boundaries, and astronomical nomenclature.