ephemeris definition, ephemeris meaning | English dictionary

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      n   pl   , ephemerides  
1    a table giving the future positions of a planet, comet, or satellite  
2    an annual publication giving the positions of the sun, moon, and planets during the course of a year, information concerning eclipses, astronomical constants, etc.  
3    Obsolete   a diary or almanac  
     (C16: from Latin, from Greek: diary, journal; see ephemeral)  

ephemeris time  
      n   time that is based on the orbit of the earth around the sun rather than the axial rotation of the earth, one ephemeris second being 1/31556925.9747 of the tropical year 1900. It was used from 1960 to 1983 as an astronomical timescale but has been replaced by terrestrial dynamical time and barycentric dynamic time  
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