The universe on our bench

This post was written by Tabea Rude

My colleague Amélie Bezárd and I had the chance to take a very close look at a so-called ‘Chronoglobium’ invented and built by Mathias Zibermayr in the first half of the 19th century in Brno (today’s Czech Republic) and Graz (Austria).

Chronoglobium
The chronoglobium in situ in the Vienna clock museum

His invention, a terrestrial globe driven by a gear train including small models of the Sun and Moon within a static glass celestial globe, was intended as a teaching device to demonstrate the movements of the heavenly bodies.

Zibermayr built at least 18 of these machines, which enjoyed great popularity not just at the time, but also much later when this particular model entered the Vienna Clock Museum in 1951. Almost immediately, it appeared in the Vienna newspapers and on the museum catalogue cover page.

Chronoglobium without sphere
The chronoglobium without celestial globe, front view

The machine can either be operated using a hand crank to show the movements as a time-lapse, or by a spring-driven clock movement, which also shows the time of day and day of the week.

Within the glass sphere, the shadow-hoop with ecliptic stands vertically, screwed into the back of the supporting Atlas figure. The outer hoop is fixed and shows the day of the month indication. The inner ecliptic is a gear wheel that is firmly attached to the models of Sun and Moon.

These models are attached on long arms on the rear side of the Chronoglobium. The model Sun is firmly attached on the ecliptic with a fan-like grid indicating the direction of Sun rays onto Earth.

Chronoglobium with Moon and Sun
The chronoglobium, side view, with the models of Sun and Moon visible

The model Moon is moved by way of a mechanism including two wheels and two lever arms up and down to demonstrate the elliptical movement of the Moon in relation to the Earth. The models of Moon and Sun perform a whole rotation around the terrestrial globe once a ‘year’, indicated by the moving ecliptic.