Royal Observatory Greenwich, Where Time and Longitude Converge

Royal Observatory Greenwich, Blackheath Avenue, Greenwich, London, Greenwich, Greater London SE10 8XJ, UK

The place where the prime meridian is located

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Introduction

The Royal Observatory in Greenwich, London was built in 1675 by King Charles II. It is a comprehensive astronomical observatory located on a small hill in Greenwich Park overlooking the River Thames. Today, it is a museum that houses collections of astronomical and navigational tools. The most famous of these are the H4 marine chronometer and its first three prototypes, which provided accurate timekeeping for navigation in history. In addition, the museum also displays other artificial timers used for astronomical and navigational purposes, such as the Fedchenko clock made in the mid-20th century by the Soviet Union, and the 28-inch refracting telescope made by Grubb in 1893. Outside the observatory gate, visitors can also see the shepherd clock, an early electronic clock. In addition, the prime meridian, which divides the globe, is marked on the ground in the courtyard of the observatory, with the east and west hemispheres marked on either side of the line.