Accession No

6058


Brief Description

mechanical crank-work (projecting) planetarium (orrery) in wooden box, in style of astronomical magic lantern slide, English [attributed], 1825 (c)


Origin

England [attributed]


Maker


Class

astronomy; demonstration


Earliest Date

Jan. 1, 1797


Latest Date

Dec. 31, 1846


Inscription Date


Material

metal (brass); wood; cloth (velvet); glass; ivory


Dimensions

box dimensions: 208mm by 151mm; height 37mm


Special Collection


Provenance

Purchased from Tesseract, Box 151, Hastings-on-Hudson, New York 10706, U.S.A., on or before 26/4/2005. Catalogue 79. Purchased with aid from the PRISM fund.


Inscription


Description Notes

Brass mechanical crank-work (projecting) planetarium (orrery) in wooden box; in style of magic lantern slide; English (?); c. 1825.

crank-work mechanism is set on a rectangular brass plate, turned by a brass crank with a detachable ivory handle on the obverse.

The obverse is fitted with a raised brass ring that carries the twelve signs of the Zodiac, in cut brass silhouettes, the sign for Scorpio has some loss to the tail. The hole cut for the Sun is covered with a plate of glass. Around the Sun are two rings with holes cut in them for Mercury and Venus, which pass under raised eccentric rings to demonstrate their phases. The ring for the Earth has an inclined three dimensional hemisphere, the moon rotates around the earth with an eccentric ring on the reverse side. Three outer planets are present but fixed on the plate, Jupiter, Saturn and Uranus. Each has an raised band above rotating rings that carry. Jupiter surrounded with 4 rings, Saturn 7 and Uranus 6 [see notes for dating the planetarium].
The reverse shows some of the gearing mechanism, part of the inner gears are covered.

The box is part fitted, the planetarium sits on a ledge and the crank fits behind a wooden block and has a hole crudely cut into the box for the ivory handle. The lid shuts with two brass hooks.

Condition: good (loss to one Zodiac silhouette); complete; box good/fair (loss to beading at base)


References

James Hyslop; 'A projecting planetarium'; Explore Whipple Collections online article; Whipple Museum of the History of Science; University of Cambridge; 2015: https://www.whipplemuseum.cam.ac.uk/explore-whipple-collections/astronomy/projecting-planetarium


Events

Description
A Planetarium is a device used to demonstrate the relative motions and positions of the Sun, planets and their moons. Physical models of the Solar System’s celestial bodies that use geared mechanisms are commonly known of as orreries, named after Charles Boyle, the 4th Earl of Orrery, for whom such an instrument was made in around 1712.

This projecting planetarium demonstrates another way in which a geared mechanism can be designed to model the Solar System. This instrument projects images of the planets and their moons, along with the signs of the Zodiac, onto a surface when a light is shined upon its reverse. By winding the handle, the instrument’s complex mechanism of cogs moves around plates containing holes through which the light can shine. Each plate turns such that the relative rotation of the planets around the sun, and the moons around the planets, is modelled by dots of light moving upon the projection surface.

The Roman philosopher Cicero credited the 3rd-century BCE Greek mathematician and astronomer Archimedes as the founder of the branch of mechanics devoted to the construction of planetaria. More recent scholars have argued that Plato’s dialogue, the Timaeus, suggests that Plato’s Academy may have had some form of planetary model in the 4th century BCE. While models by neither of these great thinkers survive, the Antikythera mechanism, as the earliest known surviving instrument to model planetary motions, demonstrates that by the 1st Century BCE extremely complex mechanical geared planetaria were being constructed.

01/08/2008
Created by: Joshua Nall on 01/08/2008


FM:46527

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