Coordinate system · α
Right Ascension
The celestial equivalent of longitude — the angle measured eastward along the celestial equator from the vernal equinox, conventionally expressed in hours, minutes, and seconds (24 hours around the sky). Together with declination it fixes a star's place in the equatorial system, and it connects directly to sidereal time.
Highlights
- ›Celestial longitude, measured in hours from the vernal equinox
Related systems & concepts
Across the reference systems
Knowledge connections
- Associated withDeclination
- Associated withThe Equatorial Coordinate System
- Associated withSidereal Time
- Associated withDeclination
- Associated withThe Equatorial Coordinate System
Sources
The primary and reference sources this topic draws on.
- IAUInternational Astronomical Union
Official naming, definitions, constellation boundaries, and astronomical nomenclature.