Mathematisch-Physikalischer Salon: The Wondrous Course of the Planets

unter anderem ein gezeichneter Löwe, Krebs und Zwillinge

Please note that due to construction work from 19 August to 13 December 2024, the Mathematisch-Physikalische Salon is only accessible via the Wall Pavilion and the passageway of the Semper Building and unfortunately has no barrier-free access.

The Wondrous Course of the Planets

Understanding the heavens has been a dream of mankind since time immemorial. Already in Antiquity, astronomers measured the skies and mathematicians developed geometric models to predict the movements of the heavenly bodies. Nearly as old are attempts to represent these theories of the cosmos graphically. The astronomical clock, which has been in Dresden since its completion 450 years ago, represents the culmination of this centuries-old tradition. By means of subtle and sophisticated gearing, its dials depict the motion of all the visible planets in real time. Both technically and artistically, the clock is an undisputed masterpiece, and can also be seen as the most elaborate didactic device of its era.

Exhibition Site

Admission Fees normal 6 €, reduced 4,50 €, under 17 free, groups (10 persons and more) 5,50 €

Only very few of today’s museum visitors, however, have a mastery of the mathematical and astronomical concepts on which the clock is based; moreover, the cultural context underlying the clock is also largely unfamiliar. That is why the project aims to convey the function and history of the Dresden astronomical clock in a readily comprehensible manner. To bring the heavens down to Earth, animated films and hands-on models have been developed. These will enable curious visitors without prior knowledge of the subject to familiarize themselves with the clock in five stages. In the process, they will get to know some of the challenges the clock’s engineers had to meet and be shown why knowledge about the planets was of such eminent importance to rulers like August of Saxony. In addition, selected objects spread throughout the four galleries of the museum have been set in relation to the astronomical clock. Altogether, the exhibition underscores how the Dresden astronomical clock is a truly exceptional artifact, but one which is rooted in multiple ways within the contemporaneous context of material culture.

reich verzierte, goldene Uhr mit mehreren Ziffernblättern — **Planetenlaufuhr, 1563-1568** Eberhard Baldewein et al., Mathematisch-Physikalischer Salon

The Astronomical Clock
Function

This monumental clock is one of the most mechanically sophisticated and artistically refined clocks of the Early Modern period. It was commissioned by Elector August of Saxony (ruled 1553 – 1586) and created at the court of his brother-in-law, Landgrave Wilhelm IV of Hessen, following a prototype built for Wilhelm himself, which is still to be seen in Kassel today. The complex mechanism of these two clocks was calculated with the direct involvement of the Landgrave and executed under the supervision of Eberhard Baldewein.

Even before the latter clock for Dresden was completed, it was already being talked about abroad and was held to be “more beautiful, larger, and more artful” than its famous predecessor in Kassel. Neither an outbreak of the plague in Hessen nor repeated technical difficulties and cost increases diminished August’s desire to possess this technical marvel. When the clock was presented at Dresden after five long years of waiting, the Elector of Saxony was “much delighted and amused” by its many features, according to an eyewitness report. Mechanical wonders such as this astronomical clock were conspicuous symbols of power. They were intended to demonstrate to visitors to the court that with the aid of a machine the Elector could control even the complicated movements of the heavenly bodies.

On the basis of the geocentric view of the universe prevailing since late antiquity, the astronomical clock shows the orbits of the seven classical “planets” visible to the naked eye – Mercury, Venus, Mars, Jupiter, and Saturn, as well as the Sun and Moon. The position of these heavenly bodies in relation to the stars of the Zodiac, as seen from the Earth, is shown on the four sides of the clock’s tower-like structure. On top of is a silver celestial globe onto which the positions of the stars have been engraved according to the extremely precise measurements made by Wilhelm and his astronomers in his palace at Kassel. The clockwork mechanism concealed inside the tower turns the celestial globe around its own axis once a day and drives the hands of the dials on the four sides in accordance with the different speeds of the planets on their orbits in the sky (ranging from one revolution per month for the Moon to one revolution about every 30 years in the case of Saturn), also capturing the occasional periods of “retrograde” or backward motion of the planets as viewed from the Earth.