occultation

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English[edit]

Etymology[edit]

The occultation of the Sun by the Moon during the solar eclipse of 11 August 1999. A total eclipse was visible mainly in Europe.

From Latin occultātiōnem, accusative singular of occultātiō (concealment; insinuation), from occultāre, present active infinitive of occultō (to conceal, hide);[1] analysable as occult +‎ -ation.

Pronunciation[edit]

Noun[edit]

occultation (countable and uncountable, plural occultations)

  1. (astronomy) An astronomical event that occurs when one celestial object is hidden by another celestial object that passes between it and the observer when the nearer object appears larger and completely hides the more distant object.
    Synonyms: eclipse
    • 1670 January 17, John Flamstead [i.e., John Flamsteed], “An Accompt of such of the More Notable Celestial Phænomena of the Year 1670, as will be Conspicuous in the English Horizon; Written by the Learned and Industrious Mr. John Flamstead Novemb. 4 1669. and by Him Addressed and Recommended for Encouragement, to the Right Honorable, the Lord Viscount Brouncker, as President of the Royal Society”, in Philosophical Transactions: Giving Some Accompt of the Present Undertakings, Studies and Labours of the Ingenious in Many Considerable Parts of the World, volume IV, number 55, London: Printed for T. N. for John Martyn at the Bell, a little without Temple-Bar, printer to the Royal Society, OCLC 644029022, pages 1101–1102:
      [T]he diſtance of any place within this kingdom from it, will not much vary the manner of their Appearance in any of the Phænomena, except the Eclipſe of the Sun: for, in the Occultations, the Stars will appeare to paſs nearly under the ſame Angles and Spots of the Moon; []
    • 1904 December, Melville Dozier, “[Transactions for November. III. Meetings of Sections.] 2. Section of Astronomy”, in Bulletin of the Southern California Academy of Sciences, volume III, number 9, Los Angeles, Calif.: Published for the Association by R. Baumgardt & Co. 231 West First St., Los Angeles, Cal., OCLC 921919756, page 147:
      The bright star Aldebaran is to be occulted by the moon on December 20th, at about 5 o'clock pm. Aldebaran is said to be eight hundred and eighty times the mass of the sun, with a diameter of over 8,000,000 miles; a distance so great that a meteor traveling at the rate of thirty miles per second, would require over three days to cross the disk of the star. Yet, notwithstanding the immense volume, the accultation will occur in a moment, so great is the distance of the star from us, and will continue for about one hour and eight minutes.
    • 1994, C. B. Olkin; J[ames] L[udlow] Elliot, “Occultation Astrometry: Predictions and Post-event Results”, in L. V. Morrison and G. F. Gilmore, editors, Galactic and Solar System Optical Astrometry: Proceedings of the Royal Greenwich Observatory and the Institute of Astronomy workshop held in Cambridge, June 21–24, 1993, Cambridge: Cambridge University Pres, ISBN 978-0-521-46240-2, abstract, page 286:
      Stellar occultations potentially provide the highest precision data for relating solar system ephemerides to the stellar reference frame. For example, occultations by the Uranian rings can define the position of the occulted star relative to the rings to better than 0.02 mas (equivalent to a few hundred meters at the distance of Uranus). Occultations by atmospheres can be less precise than occultations by symmerical solid bodies, like rings and large asteroids, with a precision on the order of 1.0 mas.
    • 2010, David H. Levy, “When the Moon Occults a Star or a Planet”, in David Levy’s Guide to Eclipses, Occultations, and Transits, Cambridge; New York, N.Y.: Cambridge University Press, ISBN 978-0-521-16551-8, page 129:
      [] I was thrilled at the prospect of seeing the waning crescent Moon swing over Venus in the predawn sky on Wednesday morning, April 22, 2009. While the occultation was visible from much of North America, it was only in Arizona and parts of other surrounding states, where Wendee and I live, that the ingress would take place in a completely dark sky. It would be a highlight of the International Year of Astronomy, which reached its peak during 2009.
  2. The state of being occult (hidden, undetected).
    Synonyms: hiddenness, invisibility, occultness
  3. (Shia Islam) The disappearance of the messianic figure, or Mahdi, who will one day return to the world.
    • 2002, Allamah Sayyid Saeed Akhtar Rizvi, Prophecies about Occultation of Imãm Al-Mahdi (A.S.), Dar es Salaam, Tanzania: Bilal Muslim Mission of Tanzania, ISBN 978-9987-620-23-4, page 7:
      We are therefore, constantly hoping for the joy and happiness, personified in Imām al-Mahdi, the Imām who is alive at this very time, and who is himself awaiting the command of Allāh to reappear, so that he may strengthen the weak, and judge the oppressors. He will reappear "without having done Bay'ah to any oppressor". He went into occultation because he did not want [to] submit to any unjust ruler.

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References[edit]

  1. ^ Compare “occultation” in Douglas Harper, Online Etymology Dictionary, 2001–2017.

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