Horloge Astronomique

Built between 1850 and 1855 by Brother Bernardin, whose real name was Gabriel Morin, this remarkable astronomical clock, still in excellent working order, comprises 200 pinions that control 10 dials and the solar system. Brother Bernardin, a true self-taught mathematics teacher, devoted several years to its construction. After long and learned calculations, he made each piece one by one.
It shows the time, the date, the phases of the Moon, the seasons, the equation of time, the positions of the Moon, the Earth and the Sun, and the aspect of the celestial vault for Ploërmel. The planetary system includes the Earth, the Moon, Venus, Mars, Jupiter, Saturn, Uranus and the Sun (the solar system known at the time). Fortunately, in 1904, after the expulsion of the brothers, the clock was auctioned off by weight. It was listed as a Historic Monument in 1982. This astronomical clock is renowned for its great precision.
It is located in the inner courtyard of the La Mennais brothers' house, under a kiosk, and can be reached by passing through a porch. A multilingual 3D video presentation explains how it was designed and how it works (8 minutes long).
Open to the public from 9am to 6pm every day of the year. Guided tours are available on request (€2.50/person).

In the same area, you'll find the Museum of Natural Sciences, the Jean-Marie de la Mennais Museum, the new exhibition ‘The Secrets of the Mother House’ created for the bicentenary of the arrival of the Brothers in Ploërmel (on view until September 2025) and access to the beautiful chapel.