Definition of "ephemeris" [e•phem•e•ris]

• A table giving the coordinates of a celestial body at a number of specific times during a given period. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Astronomy & Astrophysics says the team "presents an accurate, long-term ephemeris," and that "they participated in all the steps of a real research program, from initial observations to the publication process, and the result they obtained bears scientific significance.""
• "Just as in a circle, it is necessary to know three points to determine the circumference; so in ascertaining the elements of a comet, three different positions must be observed before what astronomers call its "ephemeris" can be established."
• "If Cassini lasts til 2012, then they will have tracked Saturn for one quarter of its orbit, providing excellent data for the ephemeris."