right ascension

right ascension

n. Abbr. 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.

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right ascension

The position of a celestial object east of the vernal equinox along the celestial equator. Right ascension is measured in hours, minutes, and seconds from the vernal equinox (0 hours) to the point where a great circle drawn through the object and the north and south celestial poles intersects the celestial equator. Each hour corresponds to 15° of angular distance along the celestial equator for a total of 24 hours. See more at equatorial coordinate system.

Thesaurus

Noun

1.

right ascension - (astronomy) the equatorial coordinate specifying the angle, measured eastward along the celestial equator, from the vernal equinox to the intersection of the hour circle that passes through an object in the sky; usually expressed in hours and minutes and seconds; used with declination to specify positions on the celestial sphere; "one hour of right ascension equals fifteen degrees" celestial longitude, RA astronomy, uranology - the branch of physics that studies celestial bodies and the universe as a whole angular distance - the angular separation between two objects as perceived by an observer; "he recorded angular distances between the stars"