Islamic Astronomy Research Articles

Tdotu]ūsī and Copernicus: The Earth's Motion in Context

A passage in Copernicus's De Revolutionibus regarding the rotation of the Earth provides evidence that he was aware, whether directly or indirectly, of an Islamic tradition dealing with this problem that goes back to Na[sdotu]īr al-Dīn al-[Tdotu]ūsī (1201–1274). The most striking similarity is the use of comets by both astronomers to discredit Ptolemy's “proofs” in the Almagest that depended upon observational evidence. The manner in which this question was dealt with by Copernicus, as an astronomical rather than natural philosophical matter, also argues for his being within the tradition of late medieval Islamic astronomy, more so than that of medieval Latin scholasticism. This of course is bolstered by his use of non-Ptolemaic models, such as the [Tdotu]ūsī couple, that have a long history in Islam but virtually none in medieval Europe. Finally, al-Qūshjī, who was in Istanbul just before Copernicus was born, entertained the possibility of the Earth's rotation; this also opens up the possibility of non-textual transmission.

Book Review: A Rare Form of Astrolabe Construction: The Melon-Shaped Astrolabe in Arabic Astronomy

Book Review: A Rare Form of Astrolabe Construction: The Melon-Shaped Astrolabe in Arabic Astronomy

Reply to Saliba

Professor Saliba takes exception to views expressed in my Review Essay (“Conaguring the Universe: Aporetic, Problem Solving, and Kinematic Modeling as Themes of Arabic Astronomy,” Perspectives on Science 1998, vol. 6, no. 3, pp. 288–330). His criticisms and reservations mainly relate to questions about the character and the value of what I have called the hay’a project in Islamic astronomy, how and when this project was launched, and about contrasts with other projects and approaches in the same discipline, especially concerning the important question of the relations between physics and mathematics as viewed by the practitioners of the discipline. The following brief comments, kindly solicited by the editors of Perspectives on Science, are meant to sharpen some of our more serious differences, and, hopefully, to remove some misunderstandings. First, with regard to the term hay’a, Saliba makes too much of the term itself as an indication of when a new, and speciacally Islamic, project came into existence. Hay’a is a common Arabic word which means shape, agure or form; and, whether or not it originally rendered a Greek term, it could equally apply to the Aristotelian form (we now say “conaguration”) of the universe as a structure of homocentric spheres, and to the Ptolemaic system of eccentric spheres and epicycles. As Saliba knows, the term appears in the title of one manuscript of the Arabic version of Ptolemy’s Planetary Hypotheses, and could be applied to something as simple as the agure (hay’a) of the earth. That the term came to refer to the science of astronomy in general is therefore not surprising: it emphasized a tendency, prevalent among a large number of Islamic astronomers, to view astronomical theory as primarily concerned to represent the heavens in terms of nested solid spheres obeying some physically accepted principles of motion. Thus an early use of the word hay’a does not by itself imply the motivations and

Arabic versus Greek Astronomy: A Debate over the Foundations of Science

This short note is occasioned by the publication of a review essay by A. I. Sabra in this journal, under the title “Conaguring the Universe: Aporetic, Problem Solving, and Kinematic Modeling as Themes of Arabic Astronomy.” Sabra’s review itself was in turn occasioned by the recent publication of four books (all in the 1990s), two of which were written as dissertations by Sabra’s own students and under his own supervision, and the last two were written by the present author. As a review essay, Sabra’s assessment of the books under consideration is rather fair, and as far as his assessment of the present writer’s books is decidedly oattering, and, for all practical purposes, engaging enough to invite the reader to examine those books. Had Sabra’s essay review been only a review, however, it would not have been necessary to bring it once more to the attention of the readers of Perspectives on Science, except maybe to make a corrective statement or two whenever the essay strayed into error. But it proclaims to do more than that. In 52 densely printed pages, it attempts to determine the purpose and character of a whole tradition of astronomical writings that occupied a major place in Islamic civilization for slightly more than a millennium, from the ninth to the twentieth century, a Herculean task in itself. The tradition in question was the one commonly known as the hay’a tradition, whose very name is still problematic since no one has ever been able to demonstrate that the term hay’a had any Greek antecedents. Its beginnings though can be incontestably dated back to the middle of the ninth century if not before, as is evident from the work Kitab al-hay’a (Book on Astronomy) by Qusta. b. Luqa (o. 860), who was not mentioned in Sabra’s essay. Its purpose, as I shall argue below, seems to have been an attempt to set new foundations for the science of astronomy, thus giving

Configuring the Universe: Aporetic, Problem Solving, and Kinematic Modeling as Themes of Arabic Astronomy

The undoubted truth is that there exist for the planetary motions true and constant configurations from which no impossibilities or contradictions follow; they are not the same as the configurations asserted by Ptolemy; and Ptolemy neither grasped them nor did his understanding get to imagine what they truly are.

Islamic Astronomy in China: Two New Sources for the Huihui Li (“Islamic Calendar”)

In this talk we will discuss some aspects of the exchange of astronomical knowledge that took place between the Muslim world and China in the thirteenth and fourteenth century. In that period both the eastern part of the Muslim world, consisting of Persia and surrounding countries, and China, ruled by the Yuan Dynasty, were part of the Mongol world empire. In particular in the period between 1260 and 1280, astronomers as well as astronomical books and instruments were exchanged between Persia and China. As a result, extensive descriptions of a Chinese luni-solar calendar can be found in Arabic and Persian astronomical works from the Mongol period, whereas a Chinese text entitled Huihui Li (“Islamic Calendar”) can be seen to be a translation of a typical Islamic astronomical handbook with tables and explanatory text, in Arabic and Persian called zīj. Islamic astronomy had a good name in China because of its accurate prediction of eclipses, and the Huihui li was used parallel with the official Chinese calendar for almost 300 years.

Book Review: Islamic Astronomers and the Equant: A History of Arabic Astronomy: Planetary Theories during the Golden Age of Islam

Book Review: Islamic Astronomers and the Equant: A History of Arabic Astronomy: Planetary Theories during the Golden Age of Islam

Determining the Interdependence of Historical Astronomical Tables

The authorship of portions of some ancient and medieval astronomical manuscripts is a current historical issue. This article develops a statistical method for determining whether or not a link exists between a pair of mathematically defined historical astronomical tables. The existence or nonexistence of such links aids the analysis of the origins of these documents. Nonparametric methods are used to determine whether traces of the errors in one table may be found in the other, or whether the “dependent” table is too accurate to have been derived from the entries in the other table. Several applications reveal new historical information about certain tables in Claudius Ptolemy's Almagest (c. A.D. 140) and about the tables of the 14th-century Islamic astronomer Shams al-Dɨn al-Khalɨlɨ.

Solar and Lunar Eclipse Measurements by Medieval Muslim Astronomers, II: Observations

Les eclipses solaires et lunaires ont ete observees et mesurees par des astronomes arabes du Moyen Age. Leurs documents et leurs calculs ont ete traduits

Writing the History of Arabic Astronomy: Problems and Differing Perspectives

This review article of two editions of a medieval Arabic astronomical text raises a series of methodological questions relating to the writing of the general history of Arabic astronomy. These include, among others, the purpose of modern textual editions, their translations and the commentaries accompanying them, and the audience intended, as one addresses varying cultural requirements. Discussion of one of these works in particular also provides the opportunity to raise questions relative to the nature of manuscript evidence and the manner in which such evidence is deployed in modern studies, and the role of medieval commentaries in elucidating edited texts as well as the credence one should accord to the statements of medieval commentators on subjects beyond the immediate text with which they were concerned. Moreover, this essay focuses on the need to investigate the provenance of Arabic and Persian manuscripts now held in major European libraries (especially those in Italy and France), as it highlights the utility of such research in settling recently raised questions regarding the transmission of Arabic science to Europe during the Renaissance. Finally, evidence of such transmission raises the further question of its relevance for the ongoing debate regarding the influence of medieval Islamic astronomy on the works of Copernicus.

Book Review: Studies in Islamic Astronomy: Astronomy in the Service of Islam, Islamic Astronomy and Medieval Spain

Book Review: Studies in Islamic Astronomy: Astronomy in the Service of Islam, Islamic Astronomy and Medieval Spain

Solar and Lunar Eclipse Measurements by Medieval Muslim Astronomers, I: Background

Les donnees, les techniques d'observation et les remarques de 3 astronomes musulmans du Moyen Age ayant determiner les calculs d'eclipses solaire et lunaire sont discutees

A History of Arabic Astronomy: Planetary Theories during the Golden Age of Islam. George Saliba

Previous articleNext article No AccessBook ReviewsA History of Arabic Astronomy: Planetary Theories during the Golden Age of Islam. George Saliba F. Jamil RagepF. Jamil Ragep Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Isis Volume 87, Number 1Mar., 1996 Publication of the History of Science Society Article DOIhttps://doi.org/10.1086/357421 Views: 7Total views on this site Copyright 1996 History of Science Society, Inc.PDF download Crossref reports no articles citing this article.

Islamic Astronomy and Medieval Spain. Julio Samso

Islamic Astronomy and Medieval Spain. Julio Samso

New Moon's Visibility and International Islamic Calendar for the American Region 1407H - 1421H

The International Islamic Calendar Programme relies on calculationsof the new moon's expected visibility. The term "new moon's visibility"gives a wrong connotation, because the astronomical term "new moon"refers to a moon that is completely dark and invisible. Therefore, fromhere on the term "crescent moon" or simply "crescent" will be used for amoon that could be visible after the new moon phase.The problem of predicting the crescent moon's visibility has been ofinterest to astronomers in general for a friendly competition of sightinga young crescent moon and to Muslims for their needs associated withthe Islamic calendar. The earliest astronomical criterion for visibilityappeared in the Babylonian era: the moon's age after conjunction mustbe more than 24 hours, an arc of separation as must be more than 12° orthe moon sets 48 minutes after sunset. Hindus (500-700 C.E.) developeda more elaborate system of calculations with the same as >= 12° criterion.In the eighth to tenth centuries C.E., Muslim astronomers, notablyYa'qub ibn Tariq, Habash, al Khwarizmi, al Farghani, and al Battaniexcelled in mathematical astronomy and developed rules for predictingthe crescent's visibility based on the importance of the crescent's width.A century later, al Biruni recommended al Battani's procedures. In thefifth century, al Sufi and al Kashani still quoted the early Babylonian criterionof as >=12° .In the late part of the nineteenth century, Schmidt recorded observationsin Athens, Greece, throughout a period of twenty years. Fotheringham(1910) and Maunder (1911), who used Schmidt's data and thenadded some more observational data, made the first significant developmentsin criterion for visibility since the time of al Battani. Bruin (1977)developed an independent physics-based criterion involving such variablesas the sky's brightness, contrast, the crescent's intensity, and so on.However, his criterion was only theoretical and its validity needed to beproven by actual observations. Ilyas (1981) modified Bruin's criterion inorder to remove the discrepancy in his method and the actual observationalcriterion of Maunder. All of these suggested criteria for calculatingexpected visibility have been summarized in a tabular form on page15 ...

Applications of Folk Astronomy and Mathematical Astronomy to Aspects of Muslim Ritual

Modern accounts of Islamic astronomy, with their emphasis upon technical achievements, tend to ignore the simple, popular astronomy which flourished alongside mathematical astronomy in the Islamic world throughout the medieval period. This popular tradition was far more widely practised than mathematical astronomy but has not yet received the attention it deserves. This paper will discuss the two main trends in Islamic astronomy and then point to the areas of interaction and overlap of interest between them.

Aspekte angewandter Wissenschaften in Moscheen und Klöstern (Teil I)

AbstractOnly recently have the abundant sources relating to the application of astronomy to the needs of religious ritual in medieval Islam been studied, and it is now possible to write a new chapter in the history of Islamic astronomy. Simple techniques were advocated by the scholars of the religious law, highly sophisticated and complicated solutions were proposed by the Muslim scientists. It is not without interest to compare and contrast this activity, which lasted over a millennium, with that of the monks of the Christian Middle Ages. The history of the latter has not yet been written, and cannot be written from textual sources alone, as is clearly shown by some of the astronomical instruments presented here. The present essay, in which both the Islamic and Christian traditions are discussed side by side for the first time, is very much a preliminary venture, primarily intended to point to the inherent interest of the available materials for the history of science as well as for several other disciplines.

A history of Arabic astronomy: planetary theories during the golden age of Islam

A History of Arabic Astronomy is a comprehensive survey of Arabic planetary theories from the eleventh century to the fifteenth century based on recent manuscript discoveries. George Saliba argues that the medieval period, often called a period of in Islamic intellectual history, was scientifically speaking, a very productive period in which astronomical theories of the highest order were produced. Based on the most recent manuscript discoveries, this book broadly surveys developments in Arabic planetary theories from the eleventh century to the fifteenth. Taken together, the primary texts and essays assembled in this book reverse traditional beliefs about the rise and fall of Arabic science, demonstrating how the traditional age of decline in Arabic science was indeed a Golden Age as far as astronomy was concerned. Some of the techniques and mathematical theorems developed during this period were identical to those which were employed by Copernicus in developing his own non-Ptolemaic astronomy. Significantly, this volume will shed much-needed light on the conditions under which such theories were developed in medieval Islam. It clearly demonstrates the distinction that was drawn between astronomical activities and astrological ones, and reveals, contrary to common perceptions about medieval Islam, the accommodation that was obviously reached between religion and astronomy, and the degree to which astronomical planetary theories were supported, and at times even financed, by the religious community itself. This in stark contrast to the systematic attacks leveled by the same religious community against astrology. To students of European intellectual history, the book reveals the technical relationship between the astronomy of the Arabs and that of Copernicus. Saliba's definitive work will be of particular interest to historians of Arabic science as well as to historians of medieval and Renaissance European science.

A Non-Ptolemaic Lunar Model From Fourteenth-Century Central Asia

As early as the ninth century, Muslim astronomers started refining the Ptolemaic astronomy which, by this time, had been fully adopted as the framework of their research. Already, in the early part of this century, refinements were based on improved observational techniques, and included a variety of phenomena such as the length of the seasons, the solar equation, mean motion parameters, and many others.

The Astronomical Tradition Of Maragha: A Historical Survey And Prospects for Future Research

This paper surveys the results established so far by the on-going research on the planetary theories in Arabic astronomy. The most important results of the Maragha astronomers are gathered here for the first time, and new areas for future research are delineated. The conclusions reached demonstrate that the Arabic astronomical works mentioned here not only elaborate the connection between Arabic astronomy and Copernicus, but also that such activities, namely the continuous reformulation of Greek astronomy, were not limited to a specific group of astronomers or to a specific geographical area. It is shown that such activities were spread over a period of more than seven hundred years, from the early eleventh till the sixteenth century, and over an area stretching from the Andalusian peninsula in the west to the farthest reaches of Central Asia in the east.