Orrery by James Ferguson
From Object Wiki
| Orrery | |
|---|---|
 | |
| Manufacturer | James Ferguson |
| Production years | 1533-35 |
| Production location | Nuremberg, Germany |
This simple orrery, by the self-taught Scottish astronomer, instrument-maker and lecturer James Ferguson, is made almost entirely of wood. It is driven by string belts passing around pulleys, as described by Ferguson in 1747.
The orrery demonstrates the annual revolution of the earth around the sun, the rotation of the moon’s orbit, the approximate phase of the moon (shown by a pointer on the spindle which carrries the sun) and the motion of the Moon’s apogee.
[edit] How it works
The circles around the Earth are calibrated to show the signs of the Zodiac and the position of the Moon’s ascending and descending nodes. The main calendar scale on the base shows the Sun’s position in the sky as seen from the Earth. The lunar scale shows the Moon’s angular orbital position and inclination with respect to the ecliptic. A table shows ‘the time of the mean new moon in January, and of the conjunction of the sun with the Moon’s ascending node’ for the years 1760-1800.
[edit] In the Science Museum
Inv. No: 1934-134. This object will be on loan to a special exhibition in Florence in 2009.
[edit] Further Information
- Ferguson, J. The description and use of a new four wheel’d orrery, London, 1747.
- Milburn, J.R. and King, H.C., Wheelwright of the Heavens: the life and works of James Ferguson FRS, Vademecum Press, 1988.
- Rothman, P. By the light of his own mind: the story of James Ferguson, astronomer, Notes and Records of the Royal Society, 54, 1 January 2000.