Nur Ed-Din Al Betrugi
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Nur ad-Din al-Betrugi (also spelled Nur al-Din Ibn Ishaq Al-Bitruji and Abu Ishâk ibn al-Bitrogi; another spelling is al Bidrudschi) (known in the West by the Latinized name of Alpetragius) (died ca. 1204 AD) was an Arab astronomer and philosopher of the Islamic Golden Age (Middle Ages). Born in present-day Morocco, he settled in Seville, in Andalusia. He became a disciple of Ibn Tufail (Abubacer) and was a contemporary of Averroës.

The Alpetragius crater on the Moon is named after him.

Works

Al Betrugi wrote the Kitab-al-Hay’ah (Arabic,كتاب الحياة), translated from the Arabic into Hebrew, and then into Latin (printed in Vienna in 1531).

He advanced a theory on planetary motion in which he wished to avoid both epicycles and eccentrics,¹ and to account for the phenomena peculiar to the wandering stars, by compounding rotations of homocentric spheres. This was a modification of the system of planetary motion proposed by his predecessors, Ibn Bajjah (Avempace) and Ibn Tufail (Abubacer). His efforts were unsuccessful in replacing Ptolemy's planetary model, due to the numerical predictions of the planetary positions in his configuration being less accurate than that of the Ptolemaic model,² mainly because he followed Aristotle's notion of perfect circular motion.

See also

• List of Arab scientists and scholars

References

External links

• A. Zahoor, "Alpetragius"

This article incorporates text from the public-domain Catholic Encyclopedia of 1913.

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