Kepler in Ulm

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 Central Library and the City Hall

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.

Entrance to the Central Library (with reflections)

My photos in this post are from 2005. I revised the text in 2021.

See more posts on Ulm, Germany.
See also: The Kepler Museum in Prague, Czechia (Czech Republic).

13 thoughts on “Kepler in Ulm”

  1. I love the look of that library which surprises me, but what I really love is that the Frankfurt Book Fair has been around for so long (even before printing was common).

    1. Yes, I was surprised to learn that there was a book fair here in Frankfurt as early as 1370 — then for hand-copied books, of course. The annual book fair for printed books began around 1450 and lasted for over two hundred years before losing out to the competing book fair in Leipzig.

  2. “having successfully defended his mother in court, when she was on trial for witchcraft”
    That is impresssive: I had the impression that nearly no one survived such an accussation, and that anyone trying to actually defend an accused witch usually burned alongside her. Thank you for enlightening me!
    stay safe,

    1. Yes, it was highly unusual for there to be any defense at all. I’m sure Kepler’s prestige was helpful — he was a famous astronomer (and astrologer) and held the title of Imperial Mathematician. For some fascinating details of the trial, click on the link in the first comment above.

  3. Considering we’ve heard so much about Kepler and his contributions to mathematics and astronomy, it’s neat to see it in a city that he set foot in. Stepping into a place with fame for its historic legends is a lot different than merely reading about the famous individuals in a textbook…to be where they had once been present in is kind of extraordinary to imagine!

    1. No, I don’t know of any connection between Kepler and the Astronomical Clock, even though Kepler lived and worked in Prague from 1600 to 1612. For most of this time he was the Imperial Mathematician, after the death of his predecessor Tycho Brahe.

  4. I used to work closely with publishers who attended the Frankfurt book fair every year (as well as Bologna) – I wonder if they realised it went back so far?! I do like the look of that library and the cafeteria sounds worth a visit for sure 🙂

    1. I went to the Frankfurt Book Fair every year for well over thirty years, and I was never aware of its early beginnings. One of the reasons I finally stopped going was that I realized I no longer knew anyone who would be there. In earlier decades there were people I only saw once a year, at the Frankfurt Book Fair.

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