A tabulation showing the calculated future positions of the sun, moon, and planets, together with other useful information for astronomers and navigators. It is published at regular intervals.
Astronomy
A table giving the predicted positions of a celestial object at given times; pl.ephemerides. Collections of ephemerides for various objects are published in yearly almanacs, such as TheAstronomical Almanac.
Geology and Earth Sciences
The position in the sky of an astronomical object or artificial satellite at a specified date and time.