Islamic Astronomical Instruments

This volume of 12 studies, mainly published during the past 15 years, begins with an overview of the Islamic astronomy covering not only sophisticated mathematical astronomy and instrumentation but also simple folk astronomy, and the ways in which astronomy was used in the service of religion. It continues with discussions of the importance of Islamic instruments and scientific manuscript illustrations. Three studies deal with the regional schools that developed in Islamic astronomy, in this case, Egypt and the Maghrib. Another focuses on a curious astrological table for calculating the length of life of any individual. The notion of the world centred on the sacred Kaaba in Mecca inspired both astronomers and proponents of folk astronomy to propose methods for finding the qibla, or sacred direction towards the Kaaba; their activities are surveyed here. The interaction between the mathematical and folk traditions in astronomy is then illustrated by an 11th-century text on the qibla in Transoxania. The last three studies deal with an account of the geodetic measurements sponsored by the Caliph al-Ma'mûn in the 9th century; a world-map in the tradition of the 11th-century polymath al-Bîrûnî, alas corrupted by careless copying; and a table of geographical coordinates from 15th-century Egypt.

This is the first investigation of one of the main interests of astronomy in Islamic civilization, namely, timekeeping by the sun and stars and the regulation of the astronomically-defined times of Muslim prayer. The study is based on over 500 medieval astronomical manuscripts first identified by the author, now preserved in libraries all over the world and originally from the entire Islamic world from the Maghrib to Central Asia and the Yemen. The materials presented provide new insights into the early development of the prayer ritual in Islam. They also call into question the popular notion that religion could not inspire serious scientific activity. Only one of the hundreds of astronomical tables discussed here was known in medieval Europe, which is one reason why the entire corpus has remained unknown until the present. A second volume, also to be published by Brill, deals with astronomical instruments for timekeeping and other computing devices.

In the Middle Ages the astrolabe was the best known and most widely used astronomical instrument both in the Islamic world and in the West. The oldest extant description of the construction of this instrument was written by the well-known Arabic astronomer al-Farghani (Baghdad, ca. 856). His treatise is especially valuable because of the tables it contains to enable an artificer to draw the various circles and arcs on the instrument. The Arabic text of this work, including the tables, is presented here for the first time in a critical edition, accompanied by an English translation and a commentary reproducing al-Farghani's reasoning in modern mathematical notation.

In On Both Sides of the Strait of Gibraltar Julio Samsó shows that astronomical sources, written in al-Andalus, the Maghrib and the Iberian Peninsula, belong to the same tradition and emphasizes the role of al-Andalus and the Iberian Peninsula in the transmission of Islamic astronomy to medieval Europe.

This is the fourth set of studies in the Variorum series by David King, a leading authority on the history of Islamic astronomy and on medieval astronomical instruments. The first of the studies collected here deals with medieval instruments as historical sources. The following papers focus on individual astrolabes from the European Middle Ages and early Renaissance that are of singular historical importance and look at the origins of the simple universal horary quadrant and the complicated universal horary dial (navicula). The collection concludes with a list of all known medieval European astrolabes.

This study of mathematical instrumentation in the Mamluk world contains the edition and translation of a unique, richly-illustrated treatise, and provides a fascinating historical account of several instrument models that were thus far unknown or inadequately documented.

It was the astronomers and mathematicians of the Islamic world who provided the theories and concepts that paved the way from the geocentric theories of Claudius Ptolemy in the second century AD to the heliocentric breakthroughs of Nicholas Copernicus and Johannes Kepler in the sixteenth and seventeenth centuries. Algebra, the Arabic numeral system, and trigonometry: all these and more originated in the Muslim East and undergirded an increasingly accurate and sophisticated understanding of the movements of the Sun, Moon, and planets. This nontechnical overview of the Islamic advances in the heavenly sciences allows the general reader to appreciate (for the first time) the absolutely crucial role that Muslim scientists played in the overall development of astronomy and astrology in the Eurasian world.