Information AboutOrrery |
| CATEGORIES ABOUT ORRERY | |
| clocks | |
| astronomical instruments | |
| solar system | |
| scale modeling | |
| SHOPPER'S DELIGHT | |
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A normal mechanical clock could be used to produce an extremely simple orrery with the Sun in the centre, Earth on the minute hand and Jupiter on the hour hand; Earth would make 12 revolutions around the Sun for every 1 revolution of Jupiter. Note however that Jupiter's actual year is 11.86 Earth years long, so this particular example would lose accuracy rapidly. A real orrery would be more accurate and include more planets, and would perhaps make the planets rotate as well. Orreries are sometimes referred to as Planetarium s, although generally, planetariums are hemispherical theatres in which images of the night sky are projected onto an overhead surface. Orreries can range widely in size from hand-held to room-sized. According to Cicero the Greek Stoic Philosopher Poseidonius constructed an orrery, possibly similar to the Antikythera Mechanism , which exhibited the diurnal motions of the sun, moon, and the five known planets. Cicero's account was written in the First Century BC . The first modern orrery was built circa 1704 by George Graham . Graham gave the first model (or its design) to the celebrated instrument maker John Rowley of London to make a copy for Prince Eugene Of Savoy . Rowley was commissioned to make another copy for his patron Charles Boyle, 4th Earl Of Orrery , thus the name. It was presented to Charles' son John, later the 5th Earl. Art Gallery, features a group (three men, three children, and a lone woman) listening to a lecture by a ' Natural Philosopher '—the only light in the otherwise darkened room is apparently from the centre of the brass orrery. Orreries are usually not built to Scale . Some fixed Solar System Scale Models have been built and are often many kilometres in size. An innovative concept is to have people play the role of the moving planets and other Solar system objects. Such a model, called a Human Orrery, has been laid out with precision at the Armagh Observatory . SEE ALSO
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