3 articles for "Albategnius"

**Albategnius**(al-Batt&aWmacr;nī) [Astro*Index]

(858?-929) Arabian astronomer.

Born at Haran (Turkey), died near Samarra, Iraq. Abu-'ab'dullah Muhammad ibn Jabir Al-Battani (Latinized as Albategnius) carefully examined Ptolemy's work, and determined that the *aphelion* point in the Sun's orbit had moved, deriving a good value for its rate. His father was a builder of astronomical instruments, with which he determined the length of the year to greater accuracy (sufficient for use in the *Gregorian Calendar*), the correct time of *equinox* (within two hours), and a good value for the *Obliquity of the Ecliptic*. He made the first use of a table of sines for astronomical calculations, which was an essential element in the perfecting of *Spherical Trigonometry*, the great contribution of Arabic astronomy. He is credited with the development of the Albategnian System of House Division.

See also:

♦ Almagest

**Albategnius House System**[Astro*Index]

A method of house division attributed to Albategnius based on the division of the *prime vertical* into diurnal and nocturnal arcs, each in turn divided respectively into three equal parts by two *declination circles*.

See also:

♦ House Systems ♦ House: Diurnal, Nocturnal ♦ Prime Vertical ♦ Declination Circle

**Albategnius House System**[Prima]

One of several house systems, this system is attributed to the Arabian astrologer-prince Muhammed ben Gebir al Batani from the 10th century. It is a quadrant system: The prime vertical is divided into diurnal and nocturnal arcs, each of which is divided into three equal parts by two declination circles. The Albategnius system is thought by some to have given rise to the Placidian house system.

See also:

♦ House Systems ♦ House: Diurnal, Nocturnal ♦ Prime Vertical ♦ Declination Circle

Astro*Index Copyright © 1997 Michael Erlewine

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