Coordinate system
The Equatorial Coordinate System
The standard astronomical coordinate system, projecting the Earth's equator and poles onto the sky and fixing positions by right ascension and declination. Because it is tied to the slowly precessing equator and equinox, an equatorial position must be qualified by a reference frame and epoch, such as ICRS or J2000.
Highlights
- ›RA and Dec on the projected terrestrial equator — tied to an epoch
Related systems & concepts
Across the reference systems
Knowledge connections
- Associated withThe Celestial Sphere
- Associated withRight Ascension
- Associated withDeclination
- Associated withRight Ascension
- Associated withDeclination
- Associated withThe International Celestial Reference System
- Associated withThe J2000 Epoch
- Associated withProper Motion
- Associated withParallax
- Associated withThe Galactic Coordinate System
- Associated withThe Ecliptic Coordinate System
- Associated withPrecession
- Associated withThe Aberration of Light
- Associated withInternational Astronomical Union (IAU)
Sources
The primary and reference sources this topic draws on.
- IAUInternational Astronomical Union
Official naming, definitions, constellation boundaries, and astronomical nomenclature.