Abu l-Hasan Kūshyār ibn Labbān ibn Bashahrī al-Jīlī (Arabic:أبو الحسن كوشياربن لبّان بن باشهري الجيلي) (971–1029), also known asKushyar ibn Labban, was anIranian^[1][2]mathematician,geographer, andastronomer fromGilan, south of theCaspian Sea, Iran. Author ofPrinciples of Hindu Reckoning.

Kūshyār ibn Labban's main work was probably done about the beginning of the 11th century, and seems to have taken an important part in the elaboration oftrigonometry. He continued the investigations of the 10th century mathematician and astronomerAbul Wáfa, and devoted much space to this in hiszīj (book of astronomical tables)az-Zīj al-Jamī wal-Baligh ("The Comprehensive and Mature Tables"), which incorporated the improved values of the planetaryapogees observed byal-Battani.^[3] The tables were translated into thePersian language before the end of the century. He wrote also anastrological introduction and an arithmetic treatisePrinciples of Hindu Reckoning (Kitab fi usul hisab al-hind), that is extant in bothArabic andHebrew), and was translated to English in 1963.^[4]

Kūshyār Daylami's pupils included the Persian mathematicianAli ibn Ahmad al-Nasawi. Kūshyār ibn Labban is thought to have died inBaghdad.

All of Kushyar’s surviving works were composed in Arabic. The popularity of his astrological handbook is evident from its transmission in Persian, Turkish, and Chinese manuscripts.^[5]

• Kitāb fī Uṣūl ḥisāb al-Hind (Book on the Principles of Hindu Reckoning).
• Kitāb al-Asṭurlāb (Book on the Astrolabe).
• al-Madkhal fī ṣināʿat aḥkām al-nujūm, also:Mujmal al-uṣūl fī aḥkām al-nujūm (Introduction to the Art of Astrology / Summary of the Principles of Astrology).
• al-Zīj al-Jāmiʿ (The Comprehensive Astronomical Tables/Zīj).
• al-Zīj al-Bāligh (The Extensive/Mature Astronomical Tables) of which only one chapter survives.

• O'Connor, J.J.; Robertson, E.F. (2003)."Kushyar ibn Labban".MacTutor.University of St Andrews. Retrieved7 March 2023.
• Suter, Heinrich (1900).Die Mathematiker und Astronomen der Araber und ihre Werke (in German). Leipzig: Teubner.OCLC 230703086.
• Bagheri, Mohammad (2007)."Ibn Labbān, Kūshyār: Kiyā Abū al‐Ḥasan Kūshyār ibn Labbān Bāshahrī al‐Jīlī (Gīlānī)". In Thomas Hockey; et al. (eds.).The Biographical Encyclopedia of Astronomers. New York: Springer. pp. 560–1.ISBN 978-0-387-31022-0. (PDF version)

This article about an Iranian scientist is astub. You can help Wikipedia byexpanding it.

• v
• t
• e

This article about an Asian mathematician is astub. You can help Wikipedia byexpanding it.

• v
• t
• e

• 971 births
• 1029 deaths
• 10th-century Iranian mathematicians
• 10th-century Iranian astronomers
• 11th-century Iranian astronomers
• Astronomers of the medieval Islamic world
• People from Gilan province
• Iranian scientist stubs
• Asian mathematician stubs

• Articles with short description
• Short description matches Wikidata
• Articles with hCards
• Articles containing Arabic-language text
• CS1 German-language sources (de)
• All stub articles