From: Thomas Hockey et al. (eds.). The Biographical Encyclopedia of Astronomers, Springer Reference. New York: Springer, 2007, pp. 560-561
Ibn Labbān, Kūshyār: Kiyā Abū al‐Ḥasan Kūshyār ibn Labbān Bāshahrī al‐Jīlī (Gīlānī)
Born Gīlān, (Iran)
Flourished second half 10th/early 11th century
Kūshyār ibn Labbān was an eminent Iranian astronomer known for his work on astronomical handbooks (zījes) in addition to his work in mathematics and astrology. All of his scientific legacy is in Arabic. The title Kiyā (literally, “king/ruler”) was used in his time for the names of authorities and scholars. His given name, “Kūshyār,” is the arabicized form of the ancient Persian name Gūshyār, which literally means “a gift of Gūsh” or “aided by Gūsh,” Gūsh being the name of an angel in the Zoroastrianism religion that had prevailed in Iran before Islam. There remains very little information about his life. He was from Gīlān province and later moved to Rayy (near present‐day Tehran) where he met Abū Rayḥān al‐Bīrūnī. He then moved to Jurjān in Ṭabaristān, a province adjacent to Gīlān, where he worked as the astronomer at the court of the Ziyārid dynasty. We know from al‐Bīrūnī that Kūshyār learned of the Sine Theorem from the work of his contemporary Abū Maḥmūd al‐Khujandī and referred to it as al‐shakl al‐mughnī (literally, “The theorem that makes the [Menelaus Theorem] expendable”).
Kūshyār's major work in astronomy, the Jāmiʿ Zīj (Universal/Comprehensive astronomical handbook with tables) was influenced by Ptolemy's Almagest and al‐Battānī's zīj. It contains many tables concerning trigonometry, astronomical functions, star catalogs, and geographical coordinates of cities. It comprises four books (maqāla's): calculations, tables, cosmology, (containing a chapter on “Distances and sizes” of the celestial bodies and the Earth), and proofs. Al‐Nasawī (10th/11th centuries), who was supposed to have been Kūshyār's disciple, wrote a commentary on Book I. Book I was translated into Persian about one century after Kūshyār. The entire Zīj was transliterated into Hebrew characters, which may be pieced together from fragments dispersed in several Hebrew manuscripts.
Kūshyār's Bāligh Zīj (The extensive astronomical handbook with tables), to which he refers in the introduction to his astrological treatise, is not extant. Only a short chapter entitled “On the use of planets' cycles according to the Indian method” remains in a Bombay manuscript.
Kūshyār's Risāla fī al‐asṭurlāb (Treatise on the astrolabe) is extant in several manuscripts. It consists of four sections: necessary elements, other materials rarely needed, checking the astrolabe, its circles and lines, and making astrolabes. An edition of the Arabic text, prepared by Taro Mimura in Kyoto, has not yet been published, but an edition of an old Persian translation, prepared by M. Bagheri, was published in 2004.
Al‐mudkhal fī ṣināʿat aḥkām al‐nujūm (Introduction to astrology), also named Mujmal al‐uṣūl fī aḥkām al‐nujūm (Compendium of principles in astrology), is Kūshyār's famous treatise on astrology, composed around 990. Extant in numerous manuscripts, it comprises four books: an introduction and principles, prediction of world affairs, judgments on nativities and their year transfers, and choices (of suitable times). There are old Persian and Chinese translations of this work, the latter having been printed three times. There is also a Turkish commentary extant in Istanbul (Hamidiye MS 835).
As for his mathematical work, Kūshyār is noted for his Uṣūl ḥisāb al‐hind (Principles of Hindu reckoning), which is extant and deals with algorithms for arithmetic operations in decimal and sexagesimal bases. It was translated into Hebrew by Shalom ben Joseph ʿAnābī in the 15th century (Oxford, Bodleian library, MS Oppenheim 211); in modern times it has been translated into English, French, Persian, and Russian.
Al‐Bīrūnī, Abū al‐Rayḥān (1985). Kitāb Maqālīd ʿilm al‐hayʾa: La trigonométrie sphérique chez les Arabes de l'Est à la fin du Xesiècle, edited and translated by Marie‐Thérèse Debarnot. Damascus: Institut français de Damas.
Bagheri, Mohammad (1998). “The Persian Version of ‘Zīj‐i jāmiʿ’ by Kūšyār Gīlānī.” In La science dans le monde iranien à l'époque islamique, edited by Ž. Vesel, H. Beikbaghban, and B. Thierry de Crussol des Epesse, pp. 25–31. Tehran: Institut français de recherche en Iran. (M. Bagheri is preparing an edition of the original text of the jāmiʿ Zīj with English translation and commentary.)
——— (ed.) (2004). “Tarjome‐ye fārsī‐e kohan az resāle‐ye ostorlāb‐e Kūshyār‐e Gīlānī” (The Persian translation of Kūshyār Gīlānī's treatise on the astrolabe). In Sciences, techniques et instruments dans le monde iranien (Xe– XIXesiècle), edited by N. Pourjavady and Ž. Vesel, pp. 1–34 (Persian part). Actes du colloque tenu à l'Université de Téhéran (7–9 juin 1998). Tehran.
Berggren, J. L. (1987). “Spherical Trigonometry in Kūshyār ibn Labbān's Jāmiʿ Zīj.” In From Deferent to Equant: A Volume of Studies in the History of Science in the Ancient and Medieval Near East in Honor of E. S. Kennedy, edited by David A. King and George Saliba, pp. 15–33. Annals of the New York Academy of Sciences, vol. 500. New York: New York Academy of Sciences. (Berggren has translated and discussed the materials on spherical trigonometry included in Chapter 3 of Book IV of Kūshyār's jāmiʿ Zīj.)
Cecotti, Claudio (2004). “Hebrew Commentary Written by Šālom ben Joseph ʿAnābī on Kūšyār's Book ‘The Principles of Hindu Reckoning'.” In Sciences, techniques et instruments dans le monde iranien (Xe– XIXesiècle), edited by N. Pourjavady and Ž. Vesel, pp. 183–187. Actes du colloque tenu à l'Université de Téhéran (7–9 juin 1998). Tehran.
Dalen, Benno van (1994). “A Table for the True Solar Longitude in the Jāmiʿ Zīj.” In Ad Radices: Festband zum fünfzigjährigen Bestehen des Instituts für Geschichte der Naturwissenschaften der Johann Wolfgang Goethe‐Universität Frankfurt am Main, edited by Anton von Gotstedter, pp. 171–190. Stuttgart: Franz Steiner. (An analysis of two tables of this Zīj on true solar longitudes and on the equation of time.)
Ideler, Ludwig (1826). Handbuch der mathematischen und technischen Chronologie. Vol. 2. Berlin: A. Rücker. (Ideler has presented some fragments of Book I of Kūshyār's jāmiʿ Zīj with a German translation, pp. 623–633.)
Kashino, T. (1998). Planetary theory of Kūšyāribn Labbān Master's thesis, Kyoto Sangyo University, Kyoto.
Kennedy, E. S. (1956). “A Survey of Islamic Astronomical Tables.” Transactions of the American Philosophical Society, n.s., 46, pt. 2: 121–177. (Reprint, Philadelphia: American Philosophical Society, 1989.)
——— (1988). “Two Medieval Approaches to the Equation of Time.” Centaurus 31: 1–8. (Kūshyār's and al‐Kāshī's methods.)
Kūshyār ibn Labbān (1948). “Al‐abʿād wa‐ʾl‐ajrām” (Distances and sizes). In Rasāʾil mutafarriqa fī al‐hayʾa li‐ʾl‐mutaqaddimīn wa‐muʿāsirī al‐Bīrūnī. Hyderabad.
——— (1965). Uṣūl ḥisāb al‐hind (Principles of Hindu reckoning), translated into English with introduction and notes by Martin Levey and Marvin Petruck. Madison: University of Wisconsin Press.
——— (1988). “Risāla‐yi abʿād wa‐ajrām” (The treatise on distances and sizes). Persian translation by M. Bagheri. In Hezareh Gooshiar Gili, edited by M.R. Nasiri, pp. 107–126. Rasht: Gilan University.
——— (1997). Kitāb al‐Mudkhal fī ṣināʿat aḥkām al‐nujūm (Introduction to astrology), edited and translated into English by Michio Yano. Tokyo: Tokyo University of Foreign Studies.
Langermann, Y. Tzvi (1996). “Arabic Writings in Hebrew Manuscripts: A Preliminary Relisting.” Arabic Sciences and Philosophy 6: 137–160.
Rosenfeld, B. A. and Ekmeleddin Ihsanoğlu (2003). Mathematicians, Astronomers, and Other Scholars of Islamic Civilization and Their Works (7th–19th c.). Istanbul: IRCICA, pp. 118–119.
Saidan, A. S. (1973). “Kūshyar ibn Labbān ibn Bāshahrī, Abu‐ʾl‐Ḥasan, al‐Jīlī.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillipsie. Vol. 7, pp. 531–533. New York: Charles Scribner's Sons.
Van Brummelen, Glen (1988). “Mathematical Methods in the Tables of Planetary Motion in Kūshyār ibn Labbān's Jāmiʿ Zīj.” Historia Mathematica 25: 265–280. (Van Brummelen has studied Kūshyār's innovative interpolation scheme in the composition of planetary motion tables.)
Yano, Michio (1997). “Kūshyār ibn Labbān.” In Encyclopaedia of the History of Science, Technology, and Medicine in Non‐Western Cultures, edited by Helaine Selin, pp. 506–507. Dordrecht: Kluwer, Academic Publishers.
Yano, Michio and Mercè Viladrich (1990). “Tasyīr computation of Kūshyār ibn Labbān.” Historia Scientarium, no. 41: 1–16. (Includes a discussion of the concept of tasyīr [prorogation] presented in Chapter 21 of Book III.)