hour angle

the angle, measured westward through 360°, between the celestial meridian of an observer and the hour circle of a celestial body. Cf. sidereal hour angle.
[1830-40]

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 in astronomy, the angle between an observer's meridian (a great circle passing over his head and through the celestial poles) and the hour circle (any other great circle passing through the poles) on which some celestial body lies. This angle, when expressed in hours and minutes, is the time elapsed since the celestial body's last transit of the observer's meridian. The hour angle can also be expressed in degrees, 15° of arc being equal to one hour. See also right ascension.

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Universalium. 2010.

Look at other dictionaries:

  • Hour angle — Hour Hour, n. [OE. hour, our, hore, ure, OF. hore, ore, ure, F. heure, L. hora, fr. Gr. ?, orig., a definite space of time, fixed by natural laws; hence, a season, the time of the day, an hour. See {Year}, and cf. {Horologe}, {Horoscope}.] 1. The …   The Collaborative International Dictionary of English

  • hour angle — n. Astron. the angle formed at the pole, or its arc on the celestial equator, between the hour circle of a celestial object and the observer s celestial meridian measured in hours, minutes, etc.: it represents the elapsed time since the object… …   English World dictionary

  • hour-angle — hourˈ angle noun (astronomy) The angle (usu measured as time) between the declination circle of a body observed and the observer s meridian • • • Main Entry: ↑hour …   Useful english dictionary

  • Hour angle — In astronomy, the hour angle is one of the coordinates used in the equatorial coordinate system for describing the position of a point on the celestial sphere.The hour angle of a point is the angle between the half plane determined by the Earth… …   Wikipedia

  • hour angle — The angular distance west of a celestial meridian or hour circle; the arc of the celestial equator, or the angle at the celestial pole, between the upper branch of a celestial meridian or hour circle and the hour circle of a celestial body or the …   Aviation dictionary

  • hour angle — noun 1. the angular distance along the celestial equator from the observer s meridian to the hour circle of a given celestial body (Freq. 1) • Hypernyms: ↑distance 2. (astronomy) the angular distance of a celestial point measured westward along… …   Useful english dictionary

  • hour angle — valandų kampas statusas T sritis fizika atitikmenys: angl. hour angle vok. Stundenwinkel, m rus. часовой угол, m pranc. angle horaire, m …   Fizikos terminų žodynas

  • hour angle — hour′ an gle n. astron. the angle, measured westward through 360°, between the celestial meridian of an observer and the hour circle of a celestial body • Etymology: 1830–40 …   From formal English to slang

  • hour angle — noun Date: circa 1837 the angle between the celestial meridian of an observer and the hour circle of a celestial object measured westward from the meridian …   New Collegiate Dictionary

  • Greenwich hour angle — hour angle measured from the meridian of Greenwich, England. * * * …   Universalium

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