hour circle

Any great circle joining the celestial poles and passing through a point on the celestial sphere. All celestial bodies are positioned on particular hour circles. Unlike celestial meridians, which remain fixed with respect to the earth, hour circles move with the celestial sphere as it rotates about the earth. Also called a circle of declination or a circle of right ascension.

Aviation dictionary. 2014.

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  • Hour circle — 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-circle — hourˈ circle noun (astronomy) 1. A great circle passing through the celestial poles 2. The equivalent of a meridian 3. The circle of an equatorial which shows the right ascension • • • Main Entry: ↑hour …   Useful english dictionary

  • hour circle — n. Astron. any great circle of the celestial sphere which passes through the celestial poles and is therefore perpendicular to the celestial equator …   English World dictionary

  • hour circle — Astron. a great circle on the celestial sphere passing through the celestial poles and containing a point on the celestial sphere, as a star or the vernal equinox. Also called circle of declination. [1665 75] * * * ▪ astronomy       in astronomy …   Universalium

  • hour circle — noun a great circle on the celestial sphere that passes through both celestial poles • Hypernyms: ↑great circle * * * noun 1. : a circle of the celestial sphere passing through the two poles 2. : the circle upon an equatorial telescope mounted… …   Useful english dictionary

  • hour circle — hour′ cir cle n. astron. a great circle on the celestial sphere passing through the celestial poles and containing a point on the celestial sphere, as a star or the vernal equinox • Etymology: 1665–75 …   From formal English to slang

  • hour circle — noun Date: 1690 a circle on the celestial sphere that passes through both celestial poles …   New Collegiate Dictionary

  • hour circle — (Astronomy) great circle that passes through both poles of the celestial sphere …   English contemporary dictionary

  • hour-circle — n. Meridian, great circle of the sphere …   New dictionary of synonyms

  • hour circle — /ˈaʊə sɜkəl/ (say owuh serkuhl) noun any great circle in the celestial sphere passing through the celestial poles …   Australian English dictionary

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