The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
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The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
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c. 1305-c. 1375
Arab astronomer who sought to restore uniform circular motion to planetary theory by replacing Ptolemy's eccentric deferent and equant with secondary epicycles. This eliminated a major defect of Ptolemaic lunar theory by reducing the variation of the Moon's distance. Though developed within a geocentric framework, Ibn al-Shatir's models are mathematically equivalent to those later developed by Nicolaus Copernicus; however, no direct influence has been established. Ibn al-Shatir also constructed various instruments, including sundials, astrolabes, and quadrants.