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Astrolabe Longcase Clock

Thomas Tompion, England’s greatest clockmaker, was the son of a Bedfordshire blacksmith. He was living in London by 1671, when he was admitted to the Clockmakers’ Company as  Free Brother – a man who had served his apprenticeship under another Company – and was described as a maker of ‘Great Clocks’, indicating iron turret or church clocks, a craft often combined with blacksmithing. How he acquired his outstanding scientific and technical skills is not known. In 1674 he became a Freeman of the Company, and was its Master by 1703. He was buried in Westminster Abbey, an extraordinary honour for a craftsman. 
This astrolabe clock is one of only two known to be by him. The movement has an early form of anchor escapement, to control the pendulum and improve accuracy. The ‘face’ has a 24-hour dial, three hands telling the hour, minutes and lunar time, and apertures showing the age and phase of the moon, the time of high tide at London Bridge, and the day of the month. The astrolabe disc, added shortly after the clock was made, makes it possible to track the sun’s position in the ecliptic (its apparent path through the heavens) for each day of the year.