Libration of the moon

Definitions

  • Webster's Revised Unabridged Dictionary
    • 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.
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Chambers's Twentieth Century Dictionary
    • Libration of the moon an apparent irregularity in the moon's motion, whereby its globe seems to turn slightly round to each side alternately
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Etymology

Chambers's Twentieth Century Dictionary
L. librāre, -ātumlibra, balance.

Usage

In literature:

The last of Galileo's great astronomical discoveries related to the libration of the moon.
"Great Astronomers" by R. S. Ball
The admirable memoir of Lagrange upon the libration of the moon seemed to have exhausted the subject.
"Biographies of Distinguished Scientific Men" by Francois Arago
LIBRATION OF THE MOON.
"The Sailor's Word-Book" by William Henry Smyth
First comes a research into the libration of the moon.
"Pioneers of Science" by Oliver Lodge
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In science:

The large moon Tethys has two smaller Tro jan moons called Telesto and Calypso, one of which librates about the Saturn-Tethys L4 and the other about the Saturn-Tethys L5 points.
Asteroids in the Inner Solar System I - Existence
The predicted round-trip travel times between retroreflector and telescope also take into account the librations of the Moon, the orientation of the Earth, the location of the observatory, and atmospheric effects on the signal propagation.
The Confrontation between General Relativity and Experiment
Finally, the interior, tidal response, and physical librations (rocking) of the Moon are all probed by LLR, making it a valuable tool for physical selenography .
Improving LLR Tests of Gravitational Theory
Besides the fundamental physics capabilities of LLR, the interior, tidal response, and physical librations (rocking) of the Moon are all probed by LLR, making it a valuable tool for physical selenography .
35 Years of Testing Relativistic Gravity: Where do we go from here?
The predicted round-trip travel times between retroreflector and telescope also take into account the librations of the Moon, the orientation of the Earth, the location of the observatories, and atmospheric effects on the signal propagation.
The Confrontation between General Relativity and Experiment
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