astrarium
Illustration — The astrarium made by Giovanni Dondi dell'Orologio showed hour, year calendar, movement of the planets, Sun and Moon. Reconstruction, Museo Nazionale Scienza e Tecnologia Leonardo da Vinci, Milan. An astrarium, also called a planetarium, is a medieval astronomical clock made in the 14th century by Italian engineer and astronomer Giovanni Dondi dell'Orologio.
Also recorded as planetarium
astrarium

Pippa Luigi (costruttore) · Catalogo collezioni (Italian). Museoscienza.org. Museo nazionale della scienza e della tecnologia Leonardo da Vinci, Milano. · CC BY-SA 4.0
- Field
- orrery · astronomical clock
VALÉORINE Encyclopedia
VALÉORINE documentary reading
Documentary summary
Illustration — The astrarium made by Giovanni Dondi dell'Orologio showed hour, year calendar, movement of the planets, Sun and Moon. Reconstruction, Museo Nazionale Scienza e Tecnologia Leonardo da Vinci, Milan. An astrarium, also called a planetarium, is a medieval astronomical clock made in the 14th century by Italian engineer and astronomer Giovanni Dondi dell'Orologio.
Admitted source layer · organised and presented by VALÉORINE
Note VALÉORINE
No house-authored Note is published until its assertions and sources pass the VALÉORINE evidence contract. The documentary article remains available in full while that enrichment is being consolidated.
Documentary enrichment in progress · no unsupported statement published
Reference Check
Propose documentary evidence for astrarium. A contribution is never written directly as fact: identity, source, rights and evidence gates still decide.
Sign in to contribute
World of VALÉORINE
Documentary connections
Only confirmed graph relationships appear here. Images are shown only when their identity and reuse rights both pass the documentary gate.
Documentary evidence
Evidence Panel
not yet certified
- Identity
- resolved
- Independent source families
- 0
- Admitted assertions
- 0
- Open conflicts
- 0
Authority files
gnd · 4565679-4 · wikidata · Q2868533 · wikipedia · Astrarium
In this article
Greek and Roman World
Greek and Roman World
The Astrarium was modeled after the Solar System and, in addition to counting time and representing calendar dates and holidays, showed how the planets moved around the celestial sphere in one timepiece. This was its main task, in comparison with the astronomical clock, the main task of which is the actual reading of time. A complex mechanism, it combined the functions of a modern planetarium, clock, and calendar into a singular constructive device. Devices that perform this function were known to have been created prior to the design of Dondi, though relatively little is known about them. It is occasionally erroneously claimed by the details of some sources that the Astrarium was the first mechanical device showing the movements of the planets.
• Illustration — The Antikythera mechanism (main fragment), found in the Aegean Sea The first astraria were mechanical devices. Archimedes is said to have used a primitive version that could predict the positions of the Sun, the Moon, and the planets. On May 17, 1902, an archaeologist named Valerios Stais discovered that a lump of oxidated material, which had been recovered from a shipwreck near the Greek island of Antikythera, held within it a mechanism with cogwheels. This mechanism, known as the Antikythera mechanism, was recently redated to end of the 2nd century BCE. Extensive study of the fragments, using X-rays, has revealed enough details (gears, pinions, crank) to enable researchers to build partial replicas of the original device. Engraved on the major gears are the names of the planets, which leaves little doubt as to the intended use of the mechanism. By the collapse of the Roman Empire, the know-how and science behind this piece of clockwork was lost.
Middle Ages and Renaissance
Middle Ages and Renaissance
According to historians Bedini and Maddison, the earliest astrarium clock with an "almost complete description and incontestable documentation" to have survived is the astrarium completed in 1364 by Giovanni de' Dondi (1318–1388), a scholar and physician of the Middle Ages. The original clock, consisting of 107 wheels and pinions, has been lost, perhaps during the sacking of Mantua in 1630, but de' Dondi left detailed descriptions, which have survived, enabling a reconstruction of the clock. It displays the mean time, sidereal (or star) time and the motions of the Sun, Moon and the five then-known planets Mercury, Venus, Mars, Jupiter, and Saturn. It was conceived according to a Ptolemaic conception of the Solar System. De' Dondi was inspired by his father Jacopo who designed the astronomical clock in the Piazzi dei Signori, Padua, in 1344 – one of the first of its type. In later ages, more astraria were built. A famous example is the Eise Eisinga Planetarium, built in 1774 by Eise Eisinga from Dronrijp, Friesland, the Netherlands. It displayed all the planets and was fixed to the ceiling in a house in Franeker, where it can still be visited. In modern times, the astrarium has grown into a tourist attraction as a commercially exploited planetarium-showing in IMAX theaters, with such presentations as The History of the Universe, as well as other astronomical phenomena.
Primary material
Documents and archives
reference work
- Wikidata, structured authority record Q2868533: astrarium
Reputable secondary · Wikidata
- “Astrarium”, English Wikipedia, consulted as further reading
Reputable secondary · Wikipedia
authority file
- Gemeinsame Normdatei 4565679-4, Astrarium.
Unverified · Deutsche Nationalbibliothek
Literature
• Giovanni Dondi dell'Orologio – "Tractatus astarii"
Citations
References
Each reference names the institution holding it, so a reader may go to the document itself.
authority file
Gemeinsame Normdatei 4565679-4, Astrarium.Deutsche Nationalbibliothek
Partially resolvedreference work
Partially resolvedreference work
Partially resolved
A further 1 witness is held back from this article because the person or object named in it is not yet resolved to this record. They are kept, not discarded, and return once the identity is established.
The Encyclopedia exists whether or not anything is for sale. Corrections are recorded rather than overwritten, and every version of this record is kept. Published 14 August 2026.
Elsewhere in Clocks
110 published records in this field, each with its sources named.
- Act of Parliament clockTerminology
- alarm clockTerminology
- Antikythera mechanismTerminology
- Apple II system clocksTerminology
- Astrarium of Giovanni Dondi dell'OrologioTerminology
- astronomical clockTerminology
- Astronomical clock in MessinaTerminology
- astronomical clock of BesançonTerminology
Best supported in this field
For owners
Own an object connected with astrarium?
A specialist will read what you send and tell you what the house can establish, what it cannot, and whether the object is suited to sale. There is no charge and no obligation. The object stays with you throughout; nothing is shipped to us unless it is arranged in writing beforehand.