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Historians
who track the development of astronomy from antiquity to the
Renaissance sometimes refer to the time from the eighth through
the 14th centuries as the Islamic period. During that interval
most astronomical activity took place in the Middle East, North
Africa and Moorish Spain. While Europe languished in the Dark
Ages, the torch of ancient scholarship had passed into Muslim
hands. Islamic scholars kept it alight, and from them it passed to
Renaissance Europe. The
Muslims looked upon astronomy as the noblest, the most exalted and
the most beautiful of sciences because the study of the stars
was an indispensable aid to religious observance. Arabic astronomy
was subdivided into 4 main parts: spherical astronomy,
chronometry, spherical trigonometry and mathematical geography. Two
circumstances fostered the growth of astronomy in Islamic lands.
One was geographic proximity to the world of ancient learning,
coupled with a tolerance for scholars of other creeds. In the
ninth century most of the Greek scientific texts were translated
into Arabic, including Ptolemy's Syntaxis, the apex of ancient
astronomy. It was through these translations that the Greek works
later became known in medieval Europe. (Indeed, the Syntaxis is
still known primarily by its Arabic name, Almagest, meaning
"the greatest.") The
second impetus came from Islamic religious observances, which
presented a host of problems in mathematical astronomy, mostly
related to timekeeping. In solving these problems the Islamic
scholars went far beyond the Greek mathematical methods. These
developments, notably in the field of trigonometry, provided the
essential tools for the creation of Western Renaissance astronomy. The
traces of medieval Islamic astronomy are conspicuous even today.
When an astronomer refers to the zenith, to azimuth or to algebra,
or when he mentions the stars in the Summer Triangle--Vega, Altair,
Deneb--he is using words of Arabic origin. Yet although the story
of how Greek astronomy passed to the Arabs is comparatively well
known, the history of its transformation by Islamic scholars and
subsequent retransmission to the Latin West is only now being
written. Thousands of manuscripts remain unexamined. Nevertheless,
it is possible to offer at least a fragmentary sketch of the
process. The
House of Wisdom The
foundations of Islamic science in general and of astronomy in
particular were laid two centuries after the emigration of the
prophet Muhammad, peace and blessings be upon him, from Mecca to
Medina in A.D. 622. This event, called the Hegira, marks the
beginning of the Islamic calendar. The early centuries of Islam
were characterized by a rapid expansion. Not until the late second
century and early third century of the Hegira era was there a
sufficiently stable and cosmopolitan atmosphere in which the
sciences could flourish. Then the new Abbasid dynasty, which had
taken over the caliphate (the leadership of Islam) in 750 and
founded Baghdad as the capital in 762, began to sponsor
translations of Greek texts. In just a few decades the major
scientific works of antiquity--including those of Galen,
Aristotle, Euclid, Ptolemy, Archimedes and Apollonius--were
translated into Arabic. The work was done by Christian and Pagan
scholars as well as by Muslims. The
most vigorous patron of this effort was Caliph al-Ma'mun, who
acceded to power in 813. Al-Ma'mun founded an academy called the
House of Wisdom and placed Hunayn ibn Ishaq al-'Ibadi, a Nestorian
Christian with an excellent command of Greek, in charge. Hunayn
became the most celebrated of all translators of Greek texts. He
produced Arabic versions of Plato, Aristotle and their
commentators, and he translated the works of the three founders of
Greek medicine, Hippocrates, Galen and Dioscorides. The
academy's principal translator of mathematical and astronomical
works was a pagan named Thabit ibn Qurra. Thabit was originally a
money changer in the marketplace of Harran, a town in northern
Mesopotamia that was the center of an astral cult, but he was
tolerated in the Islamic capital. There he wrote more than 100
scientific treatises, including a commentary on the Almagest. Under
the reign of al-Ma'mun (ninth century), astronomers of the Baghdad
and Damascus observatories busied themselves with verifying and
correcting Ptolemy's tables, and established the so-called
Verified Astronomical Tables of Yahya ibn Abi Mansur (A.D. 830).
Unlike Ptolemy's, these Tables took into account the precession of
the equinoxes. Observations of Venus and the sun led the same
astronomers to adopt a non-Ptolemaic model which led them to
believe that the orbit of Venus was an epicycle with a constant
center. Another
mathematical astronomer at the House of Wisdom was al-Khwarizmi,
whose Algebra, dedicated to al-Ma'mun, may well have been the
first book on the topic in Arabic. Although it was not
particularly impressive as a scientific achievement, it did help
to introduce Hindu as well as Greek methods into the Islamic
world. Sometime after 1100 it was translated into Latin by an
Englishman, Robert of Chester, who had gone to Spain to study
mathematics. The translation, beginning with the words "Dicit
Algoritmi" (hence the modern word algorithm), had a powerful
influence on medieval Western algebra. Yet
another astronomer in ninth-century Baghdad was Ahmad al-Farghani.
His most important astronomical work was his Jawami, or Elements,
which helped to spread the more elementary and nonmathematical
parts of Ptolemy's earth-centered astronomy. The Elements had a
considerable influence in the West. It was twice translated into
Latin in Toledo, once by John of Seville (Johannes Hispalensis) in
the first half of the 12th century, and more completely by Gerard
of Cremona a few decades later. Impact of these
advancements on the Renaissance The advancements made by the Muslims
in the field of Astronomy had much impact on the Renaissance.
Firstly, there ideas concerning the orbits of the planets were the
base for the many renaissance scientists who were to investigate
the heavens and eventually conclude a number of things that we now
take for granted, such as the fact that the Earth spins on its own
orbit and the sun, not the Earth, is in fact the center of our
universe. Secondly, their advancements in trigonometry had a huge
impact on many fields of Renaissance science. Using these concepts
of trigonometry, the European scientists expanded upon them and
came up with more complex formulae and equations. Additionally,
they also utilized trigonometry to construct increasingly complex
machines and devices that subsequently led to further discoveries. The Muslims' impact on navigation was also felt in the
Renaissance. European navigators relied on the Muslim concepts to
develop their own theories and methods of navigation, methods that
would eventually allow them to explore distant lands by sea.
Finally, Muslims’ astronomy was expanded upon throughout the
Renaissance, and we continue to see a form of it in everyday life,
in our newspapers and magazines. ------------------------------------------- Source: Islamic
astronomy by Owen Gingerich. Islamic-paths.org Britannica.com |