13th century AD – the Zīj-i Īlkhānī ( Ilkhanic Tables) were compiled at the Maragheh observatory in Persia.12th century AD – the Tables of Toledo – based largely on Arabic zīj sources of Islamic astronomy – were edited by Gerard of Cremona to form the standard European ephemeris until the Alfonsine Tables.9th century AD – the zīj of Muḥammad ibn Mūsā al-Khwārizmī.8th century AD – the zīj of Ibrāhīm al-Fazārī.2nd century AD – the Almagest and the Handy Tables of Ptolemy.1st millennium BC – Ephemerides in Babylonian astronomy.Some of the astronomical phenomena of interest to astronomers are eclipses, apparent retrograde motion/planetary stations, planetary ingresses, sidereal time, positions for the mean and true nodes of the moon, the phases of the Moon, and the positions of minor celestial bodies such as Chiron.Įphemerides are used in celestial navigation and astronomy. The astronomical position calculated from an ephemeris is given in the spherical polar coordinate system of right ascension and declination. However, printed ephemerides are still produced, as they are useful when computational devices are not available. Modern ephemerides are often computed electronically, from mathematical models of the motion of astronomical objects and the Earth. The calculation of these tables was one of the first applications of mechanical computers. Historically, positions were given as printed tables of values, given at regular intervals of date and time. The etymology is from Latin ephemeris 'diary' and from Greek ἐφημερίς (ephemeris) 'diary, journal'. In astronomy and celestial navigation, an ephemeris (plural: ephemerides) gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky, i.e., the position (and possibly velocity) over time. You can help by converting this article, if appropriate. This article is in list format, but may read better as prose.

Current ephemeris data