Libration Li*bra"tion (l[-i]*br[=a]"sh[u^]n), n. [L. libratio: cf. F. libration.] 1. The act or state of librating. --Jer. Taylor. [1913 Webster]

2. (Astron.) A real or apparent libratory motion, like that of a balance before coming to rest. [1913 Webster]

{Libration of the moon}, any one of those small periodical changes in the position of the moon's surface relatively to the earth, in consequence of which narrow portions at opposite limbs become visible or invisible alternately. It receives different names according to the manner in which it takes place; as: {(a)} Libration in longitude, that which, depending on the place of the moon in its elliptic orbit, causes small portions near the eastern and western borders alternately to appear and disappear each month. ({b}) Libration in latitude, that which depends on the varying position of the moon's axis in respect to the spectator, causing the alternate appearance and disappearance of either pole. ({c}) Diurnal or parallactic libration, that which brings into view on the upper limb, at rising and setting, some parts not in the average visible hemisphere. [1913 Webster]

The Collaborative International Dictionary of English. 2000.

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  • libration — [ librasjɔ̃ ] n. f. • 1547; lat. libratio ♦ Astron. Balancement apparent (d un astre, et spécialement de la Lune). « un capteur optique de la position angulaire du Soleil pour étudier la libration de Phobos » (Sciences et Avenir, 1988). ●… …   Encyclopédie Universelle

  • Libration — Libration: Die animierte Simulation zeigt den Anblick des Mondes über den Zeitraum von 27 Tagen, was einem täglichen Foto des Erdtrabanten in allen Mondphasen von Neu über Vollmond bis Neumond entspricht. Daneben ist auch seine Winkel und… …   Deutsch Wikipedia

  • Libration — (vom lat.), das Schwanken, namentlich das Schwanken des Mondes, s.d …   Pierer's Universal-Lexikon

  • Libration — (lat.), das scheinbare Schwanken des Mondes, wird erzeugt durch dessen ungleichförmige Bewegung in seiner elliptischen Bahn und durch deren Neigung zur Erdbahn; sie bewirkt, daß man statt der Hälfte nahezu 4/7 der Mondoberfläche beobachten kann …   Kleines Konversations-Lexikon

  • Libration — Libration, s. Mond …   Herders Conversations-Lexikon

  • libration — [lī brā′shən] n. [L libratio] 1. the act of librating 2. Astron. a slight rocking motion of the moon which allows 59% of the moon s surface to be visible from the earth libratory [lī′brə tôr΄ē] adj …   English World dictionary

  • Libration — This article is about astronomical observations. For molecular motion, see Libration (molecule). Not to be confused with Liberation, Libation, or Vibration. Simulated views of the Moon over one month, demo …   Wikipedia

  • Libration — Cette animation montre un ensemble de vues simulées de la Lune sur une période d un mois, comme si une photographie avait été prise chaque jour à la même heure. Elle permet de mettre en évidence le phénomène de libration lunaire. En astronomie,… …   Wikipédia en Français

  • Libration — Li|bra|ti|on auch: Lib|ra|ti|on 〈f. 20〉 Schwankung des Mondkörpers um die mittlere Lage [<lat. libratio „das Abwägen, Schwingen“; zu librare „wägen, schwingen“] * * * Li|b|ra|ti|on, die; , en [lat. libratio = das Wägen, zu: librare = wägen]… …   Universal-Lexikon

  • libration — librational, adj. /luy bray sheuhn/, n. Astron. a real or apparent oscillatory motion, esp. of the moon. [1595 1605; < L libration (s. of libratio) a balancing. See LIBRATE, ION] * * * ▪ astronomy       in astronomy, an oscillation, apparent or… …   Universalium

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