Explore the Time and Greenwich gallery

Coronavirus reopening

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Essential information

Opening times: 
10am–5.30pm daily
Royal Observatory, Meridian Line and Historic Royal Observatory, Time & Greenwich gallery, Flamsteed House

The Time and Greenwich gallery at the Royal Observatory explores why and when did we start measuring time, and how Greenwich became so connected to the science of timekeeping.

How did we know what time it was before watches became widely affordable? 

About the gallery

This gallery looks at the historical need to develop increasingly accurate time keeping. See:

  • the machines that measured the time
  • the means by which the time was shared and distributed
  • the people who used the time

Find out about Maria Belville, who from 1856–92 made a weekly call on London’s principal chronometer makers, taking with her a pocket watch set to Greenwich time. See famous timepieces including the Shepherd master clock, which drove slave dials around the Royal observatory, including the large dial outside the gates - the first clock to show Greenwich Time directly to the public; and the Lund synchronised clock, an example of a timepiece leased out to subscribers of the Standard Time & Telephone Company. The time was automatically corrected by an hourly electrical signal.

Also on display is the Knox-Johnston GPS receiver used by Sir Robin Knox-Johnston on his record-breaking round-the-world voyage of 1994. GPS relies on extremely accurate atomic timekeeping to calculate positions, and an error of just 1/100 second could put the calculation 3000km out.