The Ploërmel Astronomical Clock is a 19th-century

astronomical clock An astronomical clock, horologium, or orloj is a clock with special mechanisms and dials to display astronomical information, such as the relative positions of the Sun, Moon, zodiacal constellations, and sometimes major planets. Definition ...

Ploërmel Church Saint-Armel Ploërmel (; ; Gallo language: ''Pieurmè'') is a commune in the Morbihan department in Brittany, in north-western France. On 1 January 2019, the former commune Monterrein was merged into Ploërmel. Character of the town T ...

Brittany Brittany ( ) is a peninsula, historical country and cultural area in the north-west of modern France, covering the western part of what was known as Armorica in Roman Gaul. It became an Kingdom of Brittany, independent kingdom and then a Duch ...

, in north-west France.

History and description

The clock was built and operational by 1855. It was constructed by Brother Bernardin (1812−1876) of the Community of Brothers of The Mother House of the Brothers of Ploërmel. The clock was originally inside the monastic building, it is now displayed in a glazed kiosk in the interior court of the cloisters. It comprises an astronomical clock and an

orrery An orrery is a mechanical Solar System model, model of the Solar System that illustrates or predicts the relative positions and motions of the planets and natural satellite, moons, usually according to the heliocentric model. It may also represent ...

displaying all the planets known at that time. The Earth is especially well represented with its correct inclination and the moon encircling it

Astronomical clock

The clock has ten dials which show: *Dial 1. Solar time *Dial 2. Calendar *Dial 3. Position of the Moon, the months of the year, seasons and signs of the

zodiac The zodiac is a belt-shaped region of the sky that extends approximately 8° north and south celestial latitude of the ecliptic – the apparent path of the Sun across the celestial sphere over the course of the year. Within this zodiac ...

*Dial 4. The

equation of time The equation of time describes the discrepancy between two kinds of solar time. The two times that differ are the apparent solar time, which directly tracks the diurnal motion of the Sun, and mean solar time, which tracks a theoretical mean Sun ...

(the difference between mean time and real time) *Dials 5 and 6. The standard time to the nearest minute for the whole world. *Dial 7. The position of the Moon, Earth and Sun. *Dials 8 and 9. The view of the heavens over Ploërmel. *Dial 10. The position of the Sun on the

ecliptic The ecliptic or ecliptic plane is the orbital plane of Earth's orbit, Earth around the Sun. It was a central concept in a number of ancient sciences, providing the framework for key measurements in astronomy, astrology and calendar-making. Fr ...

, and the centuries. The small black hand rotates once every 1000 years.Brother Bernardin’s Astronomical Clock. The Community of the Brothers of Ploërmel.

Orrery

The

Orrery An orrery is a mechanical Solar System model, model of the Solar System that illustrates or predicts the relative positions and motions of the planets and natural satellite, moons, usually according to the heliocentric model. It may also represent ...

displays the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

, Mercury,

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

Jupiter Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a Jupiter mass, mass more than 2.5 times that of all the other planets in the Solar System combined a ...

Saturn Saturn is the sixth planet from the Sun and the second largest in the Solar System, after Jupiter. It is a gas giant, with an average radius of about 9 times that of Earth. It has an eighth the average density of Earth, but is over 95 tim ...

and

Uranus Uranus is the seventh planet from the Sun. It is a gaseous cyan-coloured ice giant. Most of the planet is made of water, ammonia, and methane in a Supercritical fluid, supercritical phase of matter, which astronomy calls "ice" or Volatile ( ...

, together with the

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

, the four satellites of Jupiter and the six satellites of Saturn. It was constructed around the time of the discovery of Neptune, and before Pluto, and these two planets are not shown.

References

Astronomical clocks in France 1855 in France French inventions {{Astronomical clocks