right ascensionright ascension
Astron. the angular distance of the hour circle of a celestial body from the vernal equinox, measured eastward along the celestial equator and expressed in degrees (from 0 to 360) or, more commonly, in hours (from 0 to 24), minutes, and seconds: it is used with declination (sense ) to find an exact position in the sky: abbrev. RA
The angular distance of a celestial body or point on the celestial sphere, measured eastward from the vernal equinox along the celestial equator to the hour circle of the body or point and expressed in degrees or hours.
(plural right ascensions)
- (astronomy) The angular distance east of the vernal equinox point; the celestial equivalent of longitude.