ephemeris second


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Related to ephemeris second: universal time, Atomic Time

ephemeris second

See ephemeris time.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

ephemeris second

[ə′fem·ə·rəs ′sek·ənd]
(astronomy)
The fundamental unit of time of the International System of Units from 1960 until 1968, equal to 1/31556925.9747 of the tropical year defined by the mean motion of the sun in longitude at the epoch 1900 January 0 day 12 hours.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.