This plaque on the Ulm City Hall reads: “Johanes Kepler, Astronomer, 1571-1630, published the Rudolphine Tables here in 1627. With the so-called Keppler boiler he created the basis for an orderly system of measurements and weights in the imperial city.”
Kepler at this time was 56 years old and was famous particularly for his three laws of planetary motion (and for having successfully defended his mother in court, when she was on trial for witchcraft). He came to Ulm, despite the turbulence of the Thirty Years War, to have the Rudolphine Tables printed at his own expense at the printing shop of Jonas Saur, reputedly one of the world’s best.
An article in the local newspaper Südwest Presse explained in 2017: “Kepler wanted to personally supervise the printing, because the correct reproduction of all digits and special astronomical characters, the arrangement of tables, texts and marginalia was extremely important to the ‘profound bibliophile’ who had worked on this major work for decades. Who should buy the tome? Calendar makers, astrologers, seafarers. . .”
The Rudolphine Tables were named after Rudolf II, who had financed the beginnings of the research when he was the Holy Roman Emperor in Prague in the early 1600s. They were based on years of careful observations by Kepler’s predecessor, Tycho Brahe, as well as Kepler’s own calculations based on his laws of planetary motion. The book also included “calculation examples, as well as a star catalog with around a thousand stars, a geographical directory with coordinates, information on world history and much more. Kepler calculated until 2100.”
A nice modern touch is that the first edition of a thousand copies was finished in time for the Frankfurt Book Fair of September 1627.
While he was in Ulm, Kepler was asked by the City Council to develop a uniform system of measurements for trade. He did this by defining the exact dimensions of a cylindrical container which was cast in bronze the following year, to be used as a standard for the calibration of containers used for everyday measurements. (This bronze container still exists, apparently, and is on display in a museum in Ulm.)
The new Central Library in Ulm was opened in May 2004. It is on the Marktplatz (Market Square) near the City Hall.
The façade is made almost entirely of double glass walls, and the upper floors are in the shape of a pyramid with a height of more than 36 meters. On the fifth floor there is a readers’ cafeteria with views of the city roofs and the Ulm Minster. The building is cooled in the summer and warmed in the winter by a modern fuel-saving ventilation system.
My photos in this post are from 2005. I revised the text in 2021.