Astronomy: Biographies

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al-Ṭūsī, Nasīr al-Dīn

The Concise Oxford Dictionary of World Religions | 1997 | | Copyright

al-Ṭūsī, Nasīr al-Dīn (1201–74 (AH 598–673)). Shiʿite scholar and theologian. Born in Ṭūs (hence the name), he worked under an Ismāʿīlī ruler in Alamūt (the centre for the Assassins), and wrote Ismāʿīlī works of accepted and great authority, but his own personal allegianace is uncertain. He compiled the astronomical tables known as Zīj al-Khānī, and introduced into astronomy ‘the Ṭūsī couple’. Writing on virtually all subjects, his most enduring works were al-Akhlāq al-Nāsiriyya (1235, The Nasiriyyan Ethics) and Tajrīd al-Iʿtiqādāt (The Definition of the Articles of Faith).

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JOHN BOWKER. "al-Ṭūsī, Nasīr al-Dīn." The Concise Oxford Dictionary of World Religions. 1997. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>.

JOHN BOWKER. "al-Ṭūsī, Nasīr al-Dīn." The Concise Oxford Dictionary of World Religions. 1997. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O101-alsNasralDn.html

JOHN BOWKER. "al-Ṭūsī, Nasīr al-Dīn." The Concise Oxford Dictionary of World Religions. 1997. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O101-alsNasralDn.html

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al-Ṭūsī, Naṣīr al-Dīn

A Dictionary of Astronomy | 1997 | Copyright

al-Ṭūsī, Naṣīr al-Dīn(in older texts Nasir or Nasser Eddin) (1201–74)Arabscholar, born in modern Iran. In 1259 he persuaded the Mongol ruler Hūlāgū to build an observatory at Marāgha in Persia equipped with large quadrants. From observations with these instruments, al‐Ṭūsī compiled accurate tables of planetary motion and the positions of stars. He refined the Ptolemaic system by replacing the epicycle with a small circle rolling around inside the circumference of another circle of twice the radius. Any point on the smaller circle then describes a straight line. The Tusi couple, as this device is called, was later used by N.Copernicus.

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"al-Ṭūsī, Naṣīr al-Dīn." A Dictionary of Astronomy. 1997. Encyclopedia.com. 1 Jun. 2012 <http://www.encyclopedia.com>.

"al-Ṭūsī, Naṣīr al-Dīn." A Dictionary of Astronomy. 1997. Encyclopedia.com. (June 1, 2012). http://www.encyclopedia.com/doc/1O80-alsNaralDn.html

"al-Ṭūsī, Naṣīr al-Dīn." A Dictionary of Astronomy. 1997. Retrieved June 01, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O80-alsNaralDn.html

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Free newspaper and magazine articles

	International conference on Nasir al-Din al-Tusi kicks off in Baku. News Wire article from: AZR - State Telegraph Agency of the Republic of Azerbaijan; 6/16/2011
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	Writing the history of Arabic astronomy: problems and differing perspectives. Magazine article from: The Journal of the American Oriental Society; 10/1/1996