Sepher Ibronoth [astronomy and calculations of intercalation and the Jewish calender]

BEILIN, ELIEZER BEN JACOB

Israel ben Moses

Offenbach

1722

Title within architectural arch featuring Moses and Aaron, with cherubs flanking a zodiac sphere. Woodcut illustrations of hand palms on ff.23v. and 24. Spherical charts on ff. 25 and 28, mathematical tables and illustrations. Folding sheet between ff.24 and 25 with five volvelles in pristine condition, uncut ready for assembly onto the spheres on f.25. Another such folding sheet, with six volvelles for assembly onto the spheres on f. 28, is lacking. A complete copy with all volvelles is rare

Vinograd, Offenbach 63

The Jewish calendar is lunisolar; the months are reckoned by the moon and the year by the sun. The astronomical expertise required to make the necessary adjustments, mandated an interest in astronomy for religious Jews. Maimonides devotes an entire section of his Mishneh Torah to what he lists as a positive commandment “to know how to determine which is the first day of each month of the year.” Sepher Ibronoth was prepared by R. Beilin as a manual “to help an individual fulfil the commandments.” This edition is particularly beautiful with fine illustrations and volvelles for calculations. See A. J. Karp, From the Ends of the Earth-Judaic Treasures of the Library of Congress, (1991) pp.197-8