Definition of right ascension in US English:

right ascension

(also RA)


  • The distance of a point east of the First Point of Aries, measured along the celestial equator and expressed in hours, minutes, and seconds.

    • ‘Satellite orbits were computed using a GPS almanac-like representation, that is, six Keplerian parameters plus the secular drift of the right ascension of the ascending node.’
    • ‘PSR is astronomical shorthand for pulsar, while 1913 is the pulsar's right ascension in celestial coordinates.’
    • ‘The motion of the telescope to the east and west is referred to as the right ascension or hour angle of the telescope.’
    • ‘Any object on the same hour circle will have the same right ascension, just as any place on earth on the same meridian of longitude has the same longitude.’
    • ‘He has therefore divided each small circle parallel to the equator into 12 portions of 30 each and this means that the right ascension of the star referred to in the quotation is 123.’