Shepherd Gate Clock At Royal Greenwich Observatory Editorial Photo

The Greenwich clock with standard measurements. The Shepherd Gate Clock is mounted on the wall outside the gate of the Royal Greenwich Observatory building in Greenwich, Greater London. The clock, an early example of an electric clock, was a slave mechanism controlled by electric pulses transmitted by a master clock inside the main building. The network of master and slave clocks was constructed and installed by Charles Shepherd in 1852. The clock by the gate was probably the first to display Greenwich Mean Time to the public, and is unusual in using the 24-hour analog dial. Also it originally showed astronomical time which started at 12 noon not midnight.