Approximate dimensions - Diameter: 9.5" (24cm) x Height: 12" (30cm);
Larger ImageAn Orrery Movement after James Ferguson (1710 - 1776)
James Ferguson was a well respected self-taught scientist, astronomer and lecturer. Born in Keith, Scotland, he moved to London in 1743 and established himself as a successful lecturer and author. He designed several astronomical clocks and orreries, mainly for use in his lectures, and published many pamphlets and books on scientific subjects. The present orrery was created by Paul Kellar by combining two of Ferguson's designs to include both a representation of the Earth/Moon system and all six planets known at that time. The Earth/Moon mechanism is derived from Ferguson's 1755 orrery and the remaining five planets are taken from his 1762 planetarium. Ferguson's remarkable design demonstrates many of the important aspects of the monthly and annual movements of the Earth and Moon. In the production of this orrery, we are indebted to Paul Kellar, Engineer, of Peasemore, England, who is Research Director of Quantel, Ltd.
Price: £1495
(Deposit: £149.50. Remaining payment on completion.)
Ferguson used many variations of the Orrery type-models in his extensive lecture tours in the period 1761-74 and we reproduce two of his mechanisms, plus a third modern version.
The first is a simple, miniature Orrery showing the movements of the 6 planets then known, but without the complicated Moon orbit mechanism. This is hand driven via a large gear at the base of the instrument and is a very useful means of demonstrating the principle of an Orrery instrument with minimum complications.
Price £475
(Deposit: £47.50. Remaining payment on completion.)
The second reproduction demonstrates the Moon's orbit of the Earth, as the Earth itself is orbiting the Sun. This device incorporates the various phases of the Moon together with its changing declination during the lunar month. Ferguson tells a lengthy story of using the gearing in this Orrery in his dealings with a watchmaker in an argument concerning the Trinity – and he called his device the "MECHANICAL PARADOX ORRERY". Simply, the one rotation of the arm bearing the Moon orbit mechanism results in three different orbital movements. A study of the gears quickly explains how this is effected – but we will send a copy of the full alleged original story with each 'Paradox' ordered.
Price £395
(Deposit: £39.50. Remaining payment on completion.)
The third variation of Ferguson's Orrery we offer is a skeletonised version of a full Orrery powered by an electric motor to give a 22 second Moon orbit of the Earth ( the other 5 planets still maintain their relative speeds, but at an increased rate). This is an excellent shop window display feature.
Price £1395
(Deposit: £139.50. Remaining payment on completion.)