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Definition of Ephemeris time
1. Noun. (astronomy) a measure of time defined by Earth's orbital motion; terrestrial time is mean solar time corrected for the irregularities of the Earth's motions.
Category relationships: Astronomy, Uranology
Generic synonyms: Time Unit, Unit Of Time
Definition of Ephemeris time
1. Noun. (astronomy) A former standard astronomical time scale intended to overcome the drawbacks of irregularly fluctuating mean solar time, superseded in the 1970s. ¹
2. Noun. (astronomy) A modern relativistic-coordinate time scale. ¹
¹ Source: wiktionary.com
Lexicographical Neighbors of Ephemeris Time
Literary usage of Ephemeris time
Below you will find example usage of this term as found in modern and/or classical literature:
1. An Almanack for the Year of Our Lord by Joseph Whitaker (1869)
"branches of scientific work other than astronomy there has been a demand for a
unit of time that Is invariable, and the second of ephemeris time was adopted ..."
2. The Metric System (1992)
"... 1952), the second of ephemeris time (ET) is the fraction 1 ... of the tropical
year for 1900 January 0 at 12 hours ephemeris time. ..."
3. A Supplement to the Tuckerman Tablesby Michael A. Houlden, Francis Richard Stephenson by Michael A. Houlden, Francis Richard Stephenson (1986)
"... DE 102 is ET (ephemeris time), whereas that used by Tuckerman was UT (Universal
Time). In order to effect direct comparison between Tuckerman's tabular ..."
4. A Manual of Spherical and Practical Astronomy: Embracing the General by William Chauvenet (1863)
"... or ç= 0, the probable error of the observed difference would be reduced to s;
and if we have an ephemeris time probable error of which a than that of an ..."
5. First Observations in Astronomy: A Handbook for Schools and Colleges by Mary Emma Byrd (1914)
"Reference to the original notes for this date shows that longitude was then really
unknown, but that the ephemeris time of transit was reduced by a ..."
6. A Treatise on Practical Astronomy, as Applied to Geodesy and Navigation by Charles Leander Doolittle (1890)
"If the times employed in the ephemeris and in observation are both sidereal or
both mean solar, // = 3600. If the ephemeris time is mean solar and the time ..."
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