Read our COVID-19 research and news.

Back to the future. A recently rediscovered horoscope, cast by none other than Johannes Kepler.

Moonlighting by Kepler

One day in the early 17th century, an Austrian nobleman named Hans Hannibal Huetter von Huetterhofen stopped by a local astrologer's office to get his horoscope cast. The event would have gone unnoticed by posterity, but for the soothsayer: Johannes Kepler, the astronomer-mathematician (and part-time astrologer) who discovered that planets move in ellipses and set the stage for Newton's theory of gravitation. Nearly 4 centuries later, the horoscope has turned up at the University of California, Santa Cruz (UCSC), where it had lain forgotten for a hundred years.

Kepler was no fan of horoscopes. "A mind accustomed to mathematical deduction, when confronted with the faulty foundations [of astrology], resists a long, long time, like an obstinate mule, until compelled by beating and curses to put its foot into that dirty puddle," he once wrote. Nevertheless, Kepler cast horoscopes for a living throughout his life--and, though he rejected most current astrological beliefs, he "did think there was something in it," says Bruce Stephenson, a historian of astronomy at the Adler Planetarium in Chicago.

Anthony Misch, an astronomer at UCSC's Lick Observatory and an amateur book collector, discovered the forgotten horoscope in a drawer of miscellanea at the library. The yellowed document had some jotted calculations on the back; the name, date, and hour of birth of von Huetterhofen on the front. At the bottom, in German, was an annotation that made Misch's hands tremble: "In the hand of Kepler, from the collection of Kepler Manuscripts in Pulkovo." The annotation was signed, "W. Struve," and dated 1864.

Wilhelm Struve was the director of the Pulkovo Observatory near St. Petersburg, Russia, where many of Kepler's papers had come to reside after Empress Catherine bought them in 1737. The Lick Observatory's first director, Edward Holden, bought one such souvenir in Germany in 1896. Thus the document finished its circuitous path to America.