In the late 16th century, Prague was home to a flourishing Jewish community and was an important center of the Renaissance and scientific revolution. One of its denizens, David Gans, was a product of both trends. A disciple of the famed Prague rabbi Judah Loew ben Betzalel (better known as the Maharal), he also studied humanistic and scientific texts, and authored a groundbreaking work on Jewish history. Naturally, when he found out that the astronomer Tycho Brahe was a scholar in residence at an imperial castle outside of Prague, he seized on the opportunity to meet him. Dor Ben-Ari tells the story:
Gans received a warm welcome, and he remained at the castle for three weeks (likely excluding Fridays and Saturdays), learning from the best minds of the time. He described impressive and complex measuring tools beyond his imagination, as Brahe was known to have made his many discoveries without the aid of the telescope, which was still in its infancy as a scientific tool. While at the observatory, Gans also met and studied with Brahe’s assistant, Johannes Kepler. . . . Gans also made his own humble contribution by translating Hebrew astronomical texts that were otherwise unavailable to Brahe and Kepler.
In that time, the distinctions dividing science and mysticism, as well as astronomy and astrology, were fairly blurry. In fact, many scientists and scholars, Brahe and Kepler included, dabbled in occultism. Gans devoted some of his sketches to an explanation of the zodiac, but these were clearly separate from the main content of his book. Apparently, this distinction was intended to alert readers to the value of scientific observation over mystical divination. Furthermore, Gans makes a number of statements in the book that deny the use of astronomy as a means of foreknowledge.
Kepler [later] moved to Prague for a few years where he served as a scientist in service to the court. He resided just a few minutes’ walk from the Jewish Quarter, where Gans had returned to live. We know that Kepler and Gans maintained a correspondence, apparently communicating in German peppered with Hebrew, which Kepler remembered from his studies at the University of Tübingen. According to [Gans’s memoir of these encounters], Kepler even claimed that the solar system moved elliptically, similar to the Hebrew letter khaf (כ).
Read more on The Librarians: https://blog.nli.org.il/en/gans/