equinoctial day

equinoctial day
The period between two successive transits of a particular meridian on the earth by the first point of the Aries or the successive transit of vernal equinox. Since the first point of Aries is not fixed in space, and it precesses along the equinoctial 11.26 s of the arc each year, the sidereal day measured relative to Aries is minutely shorter than that measured relative to a fixed point in space. These two days are known as practical and theoretical sidereal days, respectively. An equinoctial day is the time over the upper branch of any meridian and is equal to 24 h of mean sidereal time or 23h 56m 4.09054s of mean solar time. Also called a sidereal day.

Aviation dictionary. 2014.

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  • Equinoctial — E qui*noc tial, a. [L. aequinoctials, fr. aequinoctium equinox: cf. F. [ e]quinoxial. See {Equinox}.] 1. Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line. [1913 Webster] 2. Pertaining to… …   The Collaborative International Dictionary of English

  • Equinoctial colure — Equinoctial E qui*noc tial, a. [L. aequinoctials, fr. aequinoctium equinox: cf. F. [ e]quinoxial. See {Equinox}.] 1. Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line. [1913 Webster] 2.… …   The Collaborative International Dictionary of English

  • Equinoctial line — Equinoctial E qui*noc tial, a. [L. aequinoctials, fr. aequinoctium equinox: cf. F. [ e]quinoxial. See {Equinox}.] 1. Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line. [1913 Webster] 2.… …   The Collaborative International Dictionary of English

  • Equinoctial points — Equinoctial E qui*noc tial, a. [L. aequinoctials, fr. aequinoctium equinox: cf. F. [ e]quinoxial. See {Equinox}.] 1. Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line. [1913 Webster] 2.… …   The Collaborative International Dictionary of English

  • Equinoctial time — Equinoctial E qui*noc tial, a. [L. aequinoctials, fr. aequinoctium equinox: cf. F. [ e]quinoxial. See {Equinox}.] 1. Pertaining to an equinox, or the equinoxes, or to the time of equal day and night; as, the equinoctial line. [1913 Webster] 2.… …   The Collaborative International Dictionary of English

  • equinoctial — [ē΄kwi näk′shəl] adj. [ME & OFr equinoxial < L aequinoctialis] 1. relating to either of the equinoxes or to equal periods of day and night 2. occurring at or about the time of an equinox 3. equatorial n. 1. CELESTIAL EQUATOR 2 …   English World dictionary

  • equinoctial — adj. & n. adj. 1 happening at or near the time of an equinox (equinoctial gales). 2 of or relating to equal day and night. 3 at or near the (terrestrial) equator. n. (in full equinoctial line) = celestial equator. Phrases and idioms: equinoctial… …   Useful english dictionary

  • equinoctial — I. adjective Date: 1545 1. relating to an equinox or to a state or the time of equal day and night 2. relating to the regions or climate on or near the equator 3. relating to the time when the sun passes an equinoctial point II. noun Date: 1521 1 …   New Collegiate Dictionary

  • equinoctial — /ikwəˈnɒkʃəl/ (say eekwuh nokshuhl), /ɛ / (say e ) adjective 1. relating to an equinox or the equinoxes, or to the equality of day and night. 2. relating to the celestial equator. 3. occurring at or about the time of an equinox: an equinoctial… …  

  • equinoctial — /ee kweuh nok sheuhl, ek weuh /, adj. 1. pertaining to an equinox or the equinoxes, or to the equality of day and night. 2. pertaining to the celestial equator. 3. occurring at or about the time of an equinox. 4. Bot. (of a flower) opening… …   Universalium

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