First edition of the major work by a 14th-century Spanish Jewish astronomer of Toledo. The book deals with the elements of geometry and trigonometry; the Ptolemaic model of the solar system, and the motions of the sun and moon; and the Jewish calendar and chronology. It concludes with tables and diagrams illustrating the author's theories. EJ IX, 1065; Sarton III, 691-92 ("the climax of mediaeval Jewish astronomy"); Vinograd, Berlin 289.
