Mythical piece, the astrarium is exhibited at the Musée des Arts et Métiers

As part of its Work under the magnifying glass program, designed to highlight a remarkable piece of the history of science and technology, the Musée des Arts et Métiers is exhibiting, from September 16 to November 20, 2022, the only copy of Giovanni Dondi’s astrarium (1330-1388), which comes from the scientific and museum collections of the Observatoire de Paris - PSL.

A mythical object described as the "eighth wonder of the world", the astrarium is the very first mechanical planetary clock, designed in Italy at the end of the 14th century.

Based on Ptolemy’s geocentric system, the astrarium bears witness to the knowledge of the cosmos in the Middle Ages. Its author, Dondi, imagined this complex mechanism to reproduce what was assumed to be the movement of the planets at the time, and to free himself from the complex calculations necessary to produce horoscopes.

"I have imagined, with the divine help, to realize a work where can be seen by the eye all the movements in longitude that the astronomers assign to the planets with their circles and their periodicities. Where can be noticed its numerous peculiarities that the scholars teach and that the experience shows. Where one can even have at each moment, without any tedious calculation, the positions of all the planets".

 

Giovanni Dondi d’all Orologio

Tractatus Astrarii, second half of the XIV^th century

The reconstruction presented at the Musée des Arts et Métiers was realized, from 1987 to 1989, by a team of historians, engineers and researchers of the Observatoire de Paris - PSL, under the aegis of Alain Segonds and Jean-Pierre Verdet.

This copy, faithful to the original piece that disappeared at the beginning of the XVI^th century, was constructed thanks to an in-depth study conducted by Emmanuel Poulle, director of the École des Chartes, of all of Dondi’s manuscripts, detailing the object and its manufacture, now preserved at the Padua Chapter Library.

The presentation of this Work with a magnifying glass benefited from the scientific advice of Denis Savoie, historian of astronomy, Universcience / Observatoire de Paris - PSL.

Around the exhibition

Conference : The astrarium, a mechanization of medieval astronomy
by Denis Savoie (Universcience) and Matthieu Husson (CNRS), researchers in the history of astronomy at the Observatoire de Paris
Friday September 16, 2022
From 7pm to 8:30pm