David Gans · c. 1613
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A Hebrew textbook of astronomy that presents the Ptolemaic model of the heavens for a Hebrew-reading audience, weaving the cutting-edge European science of its day together with the medieval Jewish cosmological tradition — its author having personally visited the Danish astronomer Tycho Brahe.
The work is organized into twelve sections (she’arim) and 305 numbered paragraphs (simanim), a structure that lets it be used as a reference as much as read straight through; the printed volume supplies its own index to the paragraphs.
The early sections build the sphere from the ground up. Gans fixes the celestial pole by way of the Great and Little Bear, argues that the heavens are spherical and that no other shape will serve, notes that the circle encloses more than any other figure, and divides the ecliptic into its 360 parts. He then turns to the globe as an instrument — its diameter and poles, and the circles drawn upon it: the equator, the tropics, the northern and southern circles, the meridian and the horizon, with the distances between them worked out and methods given for constructing them. What follows is the working apparatus of positional astronomy, presented in Hebrew for readers who had no access to it in Latin.
Gans is the point of contact between two worlds that are usually described as separate. He was a Prague scholar at home in rabbinic literature who also went to Benátky to visit Tycho Brahe, and Nechmad VeNa’im is what that contact produced: a serious astronomical textbook that assumes both the medieval Jewish cosmological tradition and the observational astronomy of its own moment, and treats neither as an intrusion on the other.
The book was not printed in the author’s lifetime. It first appeared at Jessnitz in 1743, more than a century after it was written, and never again — the volume opens with an apologia by the rabbi who brought it to press. That printing carries a Latin preface by the Leipzig Hebraist Johann Christian Hebenstreit, a sign of how far outside its own community the work was expected to travel. The base text here is that edition, from the National Library of Israel’s copy.
Set at the front of this edition is the author’s own front matter, which the 1743 volume does not contain. In 1612 Gans printed a prospectus at Prague to advertise the book, under the title he had chosen for it: Magen David. Those few leaves were the only part of the work he ever saw in print. He died the following year; the book was not set in type for another hundred and thirty, and by then it had acquired the name it now carries. The prospectus survives in a single damaged copy at the Bodleian Library, edited by Pavel Sládek in Aleph 22.1–2 (2022).
From it this edition restores the approbations — among them R. Yitzchak Katz, the Maharal’s son-in-law, who rests his endorsement on astronomy he had studied in his own youth, and a long commendation by R. Yom Tov Lipmann Heller, author of the Tosafos Yom Tov — and Gans’s own preface: the dedication to his two sons, his account of why he wrote the book, and his three reasons for calling it Magen David. The last of those leaves is the author’s own testimony about what he called his work, signed a year before his death.
This makes the edition a critical one in a limited sense: a single base text, with a second witness set beside it rather than merged into it. The inserted material is bracketed front and back by editorial notice, so that no reader can mistake the 1612 leaves for part of the 1743 printing; the modern edition’s section numbers are kept so passages can be cited; and nothing within the insertion is reordered or abridged, the gap at §§1–2 being the damage to the prospectus’s first leaf.
The work is accompanied here by a separate volume of editorial footnotes.
This work is citation grade: read complete against the source rather than sampled.