Maker, Devon Clocks, England. c.1980's. 7 1/2"h x 9"dia. Name comes from the original machine built by John Rowley for Charles Boyle, 4th Earl Cork and Orrery in 1712. (Maybe these should be called Rowleys instead of Orrerys!). This orrery is Heliocentric (Sun-centered) has 6 planets, Mercury, Venus, Earth (with non-functional moon), Mars, Jupiter, Saturn. Platform escapement 8 day duration. The time of day is read off two horizontal rings circling the center of the orrery.

The periods of the planets and thus the cycle of each planet represented in this orrery is as follows: Mercury 87.96 days, Venus 224.69 days, Earth 1 year, Mars 1.88 years. Jupiter 11.86 years, Saturn 29.46 years. There is, as evidenced by the photographs below, a rather complex interaction of wheelwork needed to mimic the cycles of the planets. Due to the number of wheels and their ratios a considerable amount of power is needed to drive the orrery. Two independent mainsprings are used.