ephemeris

American  

[ih-fem-er-is] / ɪˈfɛm ər ɪs /

noun

ephemerides plural

1. a table showing the positions of a heavenly body on a number of dates in a regular sequence.

2. an astronomical almanac containing such tables.

3. Archaic. an almanac or calendar.

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ephemeris British  

/ ɪˈfɛmərɪs /

noun

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

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ephemeris Scientific  

/ ĭ-fĕm′ər-ĭs /

ephemerides plural

1. A table giving the coordinates of a celestial body at specific times during a given period. Ephemerides can be used by navigators to determine their longitude while at sea and by astronomers in following objects such as comets. The use of computers has allowed modern ephemerides to determine celestial positions with far greater accuracy than in earlier publications.

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Other Word Forms

Inflected Forms

noun

• ephemerides
  plural

Etymology

Origin of ephemeris

1545–55; < Latin ephēmeris day book, diary < Greek ephēmerís diary, account book, derivative of ephḗmeros; see ephemeral

Related Words

• calendar
• journal
• yearbook