Q. & A. 711 to 1707 with solved Papers css 1971 to date

Hitti, P 573 Hitti, P 570

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Political and Cultural History of Islam

900, was rendered into Latin by Plato of Tivoli and long afterwards done directly from Arabic into Spanish under the auspices of Alfonso X, surnamed the Wise and the Astronomer. Among alMajriti’s honorific titles was al-Hasib, the mathematician, for he was considered a leader (imam) in mathematical knowledge, including menstruation. It was either he or his Cordovan disciple Abu-alHakam Amr al-Karmani’ who introduced into Spain the writings of the Ikhwan al-Safa.
The so-called Toledan tables were based upon observations made by a number of Muslim and Jewish astronomers notable among whom was al-Zarqali, abu-Ishaq Ibrahim ibn-Yahya. These tables comprised geographical information derived from Ptolemy and al-Khwarzmi and were rendered into Latin in the twelfth century by Gerard of Cremona. The works of Raymond of Marseilles were likewise largely drawn (1140) from the astronomical canons of alZarqali. Ptolemy’s exaggerated estimate of the length of the Mediterranean Sea as 62 (degree), cut by al-Khwarizmi to about 52 degree, was reduced probably by al-Zarqali to the approximately correct figure of 42 degree. Al-Zarqali was evidently the foremost astronomical observer of his age. He devised an improved type of astrolabe, called the safihah, and was the first to prove the motion of the solar apogee with reference to the stars. According to his measurements it amounted to 12.04, whereas its real value is 11.8. Compernicus quotes al-Zarqali along with al-Battani in his book De revolutionibus orbium coelestium.
In his kitab al-Hay’ah (book of astronomy), which was also translated by Gerard of Cremona, Jabir ibn-Aflah (Geber filius Affiae) sharply criticizes Ptolemy and rightly asserts that the lower planets, Mercury and Venus, have no visible parallaxes. This book of ibn-Aflah is otherwise noteworthy for a chapter on spherical and plane trigonometry. About two and half centuries before ibn-Aflah, al-Battani had popularized, if not discovered, the first notions of trigonometerical ratios as we use them today. The science of trigonometry, like algebra and analytical geometry, was largely founded by Arabs.14
According to Julio ”Andalusi astronomers were extremely interested in the development of astronomical instruments, most of which were, like the equatorium, analog computers. Only in two
Hitti. P 572
Literary & Scientific Development in Muslim Spam 665
exceptional instances do we see them designing instruments meant for use in observations. One of these is Ibn al-Zarqali armillary sphere, on whose construction he wrote a treatise which is extant in a

7th/13th century Spanish translation. This instrument seems to be a development of the astrolabon described by Ptolemy in the Almagest, V,l: Ibn al-Zarqali adds six rings to those of Ptolemy and states that the armillary sphere can be used to determine the longitudes and latitudes of the sun, moon, planets and stars.” The second observational instrument described in Andalusi sources was designed by Jabir b. Aflah, and consists of a large graduated rings (Jabir mentions a diameter of about six spans) with an axis in its centra on which rotates a graduated quadrant with an alidade and two sights. The instrument can be mounted on the plane of the meridian, oy that of the equator or on that of the ecliptic, and it has been /egarded as a predecessor of the torquetum, first described towards the end of the 13th century by Bernard of Verdun and Franco of Poland, although the similarities between the two instruments are not very clear.15

Ibn al-Zarqali seems to have been the first to design a universal instrument of this kind: 440/1048-9 saw his treatise, divided into 100 chapters, on the instrument called al-safiha alabbadiyya, for it was dedicated to the future al-Mu’tanmid b. ’Abbad, King of Seville, who was then only eight or nine years old. This instrument had on its face, a double grid of equatorial and elliptical coordinates and a ruler-horizon, while in its back, it had a zodiacal scale, an orthographic projection of the celestial sphere, a sine quadrant and a diagram which, combined with a most elaborate alidade, allowed the computation of the geocentric distance of the moon for a given time 31. At a later date he seems to have dedicated a new version of his instrument to the same al-Mu’tamid. This second species of safiha is usually called al-shakkaziyya, and appears described in treatises divided into 60 chapters. It is a simplified version of the ’abbadiyya type, with only one complete grid of equatorial coordinate (the elliptical grid is limited to the projection of the great circles of longitude which correspond to the beginning of the zodiacal sings) in its face, while back resembles that of standard astrolabe because the ortho graphic projection, the sine quardant, the lunar diagram and the sophisticated alidade have disappeared.
’ Jayyusi, P 958.

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