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Abu Mahmud Hamid ibn al-Khidr al-Khojandi[1] (known as Abu Mahmood Khojandi, Alkhujandi or al-Khujandi, Persian: ابومحمود خجندی, c. 940 - 1000) was a Muslim Transoxanian astronomer and mathematician born in Khujand (now part of Tajikistan) who lived in the late 10th century and helped build an observatory, near the city of Ray (near today's Tehran), in Iran.

Astronomy

Khojandi worked under the patronage of the Buwayhid Amirs at the observatory near Ray, Iran, where he is known to have constructed the first huge mural sextant in 994 AD, intended to determine the Earth's axial tilt ("obliquity of the ecliptic") to high precision.

He determined the axial tilt to be 23°32'19" for the year 994 AD. He noted that measurements by earlier astronomers had found higher values (Indians: 24°; Ptolemy 23° 51') and thus discovered that the axial tilt is not constant but is in fact (currently) decreasing. His measurement of the axial tilt was however about 2 minutes too small, probably due to his heavy instrument settling over the course of the observations.[2][3]

Mathematics

Khojandi stated a special case of Fermat's Last Theorem for n = 3, but his attempted proof of the theorem was incorrect. The spherical law of sines may have also been discovered by Khujandi, but it is uncertain whether he discovered it first, or whether Abu Nasr Mansur, Abul Wafa or Nasir al-Din al-Tusi discovered it first.[4][5]

Notes

References

• O'Connor, John J.; Robertson, Edmund F., "Abu Mahmud Hamid ibn al-Khidr Al-Khujandi", MacTutor History of Mathematics archive, University of St Andrews

External links

• Brummelen, Glen Van (2007). "Khujandī: Abū Maḥmūd Ḥāmid ibn al‐Khiḍr al‐Khujandī". In Thomas Hockey; et al. (eds.). The Biographical Encyclopedia of Astronomers. New York: Springer. pp. 630–1. ISBN 978-0-387-31022-0. (PDF version)
• Tekeli, Sevim (2008) [1970-80]. "Al-Khujandī, Abū Maḥmūd Ḥāmid Ibn Al-Khiḍr". Complete Dictionary of Scientific Biography. Encyclopedia.
• History of Islamic Science

На других языках

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[de] Abu Mahmud al-Chudschandi

Abu Mahmud Hamid ibn al-Chidr al-Chudschandi (arabisch أبو محمود حميد بن الخضر الخجندي, DMG Abū Maḥmūd Ḥamīd bin al-Ḫiḍr al-Ḫuǧandī, auch Abu-Mahmud al-Khujandi; * um 940 in Chudschand (heute Tadschikistan); † um 1000), auch Chodschandi, war ein persischer Astronom und Mathematiker.

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- [en] Abu-Mahmud Khojandi

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[es] Abu Mahmud Joyandí

Abu Mahmud Hamid ibn Jidr Joyandí[1] (Juyand, 940-1000) fue un astrónomo y matemático persa que vivió a finales del siglo X. Colaboró en la construcción de un observatorio en la ciudad de Ray (cerca de la actual Teherán), en Irán. Nació en Juyand (Tayikistán, por entonces parte del emirato samaní y a continuación del qarajaní). En un parque de esa localidad se puede ver un busto de bronce de este científico.

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[fr] Al-Khujandi

Abu Mahmud Hamid ibn al-Khidr Al-Khujandi est un astronome perse du Xe siècle né aux alentours de 940 et mort en 1000. Il aida à construire un observatoire à Ray, près de Téhéran, en Iran.

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[ru] Абу Махмуд аль-Худжанди

Абу́ Махму́д Хами́д ибн аль-Хизр аль-Худжанди́ (перс. ابو محمود حميد بن الخضر خجندي‎‎; ок. 940 — ок. 1000) — среднеазиатский[1][2] (персидский[3]) математик и астроном, уроженец Худжанда (совр. Таджикистан), работал в Рее. Как и многие другие известные средневековые персоны (Ибн Сина, Омар Хайям, Фирдоуси), в советское время аль-Худжанди был признан таджикским учёным[4][5].

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