Johann Jacob Zimmermann

In the early 1680s, he wrote treatises on two comets that caused widespread fears among the population; he charted their course astronomically and interpreted their meanings astrologically.

Published under the pseudonym Ambrosius Sehmann von Caminiez (an anagram of his real name), his Muthmassliche Zeit-Bestimmung set out Zimmermann's belief that the dramatic upheavals ushering in Christ's kingdom on earth would occur in or around 1693.

After spending time in Nuremberg, Frankfurt on Main, Amsterdam, and Heidelberg, the Zimmermanns settled in Hamburg, where Johann Jacob made a living as a writer and teacher.

Here they established a religious community which, while still famed in local legend, dissolved shortly after Kelpius' death in the early eighteenth century.

Zimmermann is mentioned (as "Mr. Zimmerman") in Book 3 of Isaac Newton's Philosophiæ Naturalis Principia Mathematica in 1687 (on p. 505) as having observed the Great Comet of 1680.