Finding Longitude in Greenwich

Longitude and Mapping History

During the 1700's, John Harrison developed more accurate timekeepers that allowed for effectively determining longitude. Harrison's clocks are on display at the Royal Observatory in London. These clocks were able to keep accurate time while at sea and this allowed people to determine their longitude during voyages.

One of John Harrison's clocks from the 1700s
One of John Harrison's clocks from the Royal Observatory.