Clocks & timekeeping

Royal Observatory Greenwich holds a treasure trove of some of history's most iconic timepieces. Discover the stories behind John Harrison's groundbreaking marine chronometer H1, Charles Shepherd's 'master clock', and the famous Greenwich Time Ball. Plus, find out about the history of timekeeping and its importance to society.


How can a dolphin tell the time to the nearest minute?

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In 1967, the world changed and time became a matter of atoms rather than stars.

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Who was John Harrison, and how did his clocks help to solve the problem of finding longitude at sea?

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On the centenary of Daylight Saving in Britain, Curator of Horology, Rory McEvoy looks back at its history.


Because the Earth takes a little over 365 days to orbit the Sun, we need to make adjustments to keep the seasons from drifting: leap years and even leap seconds.

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Marking the end of British Summer Time, the clocks go back in October, giving us an extra hour in bed. But why do the clocks change?

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Marking the start of British Summer Time, the clocks 'spring forward' in March, meaning we'll lose an hour's sleep.

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To avoid confusion, the correct way to express 12 o'clock is 12 noon or 12 midnight.


Our collection focuses on three key areas: precision marine timekeeping for navigators, precision timekeeping for astronomers and the broader area of domestic timekeeping and time distribution.

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Why change the clocks, which way should they go, and whose idea was it in the first place? British Summer Time (BST) explained.