in their travels through the desert. Near the end of the eighth century and during the ninth century, most important Greek texts in the sciences had been successfully translated into Arabic. Those who wrote in Arabic at the time seemed to hold Greek heritage in awe and made very few changes in the writings (Saliba, 1994).
Some concepts from Greek astronomy reached Islam in the eight-century through translations of Sanskrit and Phalavi texts. Largely non-Ptolemaic ideas were represented as well as ideas and methods altered according to the traditions of India and Iran. When more Ptolemaic ideas were added in the eighth and ninth centuries, Islamic astronomers turned their attention to the areas where these Greco-Syrian, Greco-Iranian, Greco-Indian, and Ptolemaic Byzantine traditions conflicted. The result was the development in Islam of a mathematical astronomy that was largely Ptolemaic, but in which new parameters and ideas were introduced (Pingree, 1973).
The importance of Ptolemy's Almagest was realized by astronomers writing in Arabic as soon as the text was translated into Arabic, sometime during the latter part of the eighth century or the early part of the ninth (Saliba, 1973). The Almagest, whose name in English reveals the Arabic origin of its Latin translation, was thoroughly studied and criticized by astronomers of both the eastern and western lands of the Islamic empire (ISL). Recent research has revealed that of all the Arabic astronomical writings, the theoretical analysis of Ptolemy's Almagest and the Planetary Hypothesis was probably the most original research in medieval Arabic astronomy (Saliba, 1973).
The Ptolemaic model for the planets assumes that the epicycle centers of those planets move on a circle, called the deferent, whose center does not coincide with the earth, and that they describe equal angles around yet another center, called the equant. This concept violates the principle that a...