occultation

[ok-uhl-tey-shuhn]
noun
1.
Astronomy. the passage of one celestial body in front of another, thus hiding the other from view: applied especially to the moon's coming between an observer and a star or planet.
2.
disappearance from view or notice.
3.
the act of blocking or hiding from view.
4.
the resulting hidden or concealed state.

Origin:
1375–1425; late Middle English < Latin occultātiōn- (stem of occultātiō) a hiding, equivalent to occultāt(us) (past participle of occultāre to conceal, keep something hidden, frequentative of occulere; see occult) + -iōn- -ion

preoccultation, noun
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Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
occultation (ˌɒkʌlˈteɪʃən)
 
n
1.  the temporary disappearance of one celestial body as it moves out of sight behind another body
2.  the act of occulting or the state of being occulted

Collins English Dictionary - Complete & Unabridged 10th Edition
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Etymonline
Word Origin & History

occultation
mid-15c., from L. occultationem, noun of action from occultare, from occultus (see occult).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Science Dictionary
occultation   (ŏk'ŭl-tā'shən)  Pronunciation Key 
The passage of one celestial object in front of another, temporarily blocking the more distant object from view. Occultations can provide information about the existence and measurements of the obscuring object. For example, when an asteroid passes in front of a star, the star is temporarily obscured to an observer on Earth, thus revealing the presence and approximate size of the asteroid. In 1977, astronomers were able to identify the rings around the planet Uranus when the otherwise invisible rings were observed to occult a background star. Occultations have also led to the discovery of more distant objects in space, such as binary stars and extrasolar planets. Compare transit.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Britannica
Encyclopedia

occultation

complete obscuration of the light of an astronomical body, most commonly a star, by another astronomical body, such as a planet or a satellite. Hence, a total solar eclipse is the occultation of the Sun by the Moon. By carefully measuring the decrease in the intensity of some stars as they disappear behind the Moon, astronomers can determine their angular diameters and ascertain whether they are binary systems (a pair of stars in orbit around their common centre of gravity). Astronomers are able to determine the precise sizes and shapes of planets, asteroids, and satellites, in addition to the temperatures of planetary atmospheres, from occultations of stars. During a stellar occultation on March 10, 1977, astronomers unexpectedly discovered the rings of Uranus. Compare eclipse.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
The occultation time compared to the main transit time shows the planet has a circular orbit.
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