Park Row, Greenwich, London SE10 9NF

Phone:

020-7222 1234

Website:

www.rmg.co.uk

Opening times:

Daily 10:00-17:00

How to get there:

Tube: Cutty Sark

Entry fee:

Admission charge

Standing high on Observatory Hill, with a spectacular panoramic view over the Hospital, the river and London stretching into the distance, is Flamsteed House, the earliest building of the Greenwich complex which comprises the Royal Observatory. Built in 1675–76 by Sir Christoper Wren, with the assistance of Robert Hooke, it was the first purpose-built scientific research facility in the country. The Observatory at Greenwich is no longer used to make positional observations (due to atmospheric pollution, the Royal Observatory began the move to Herstmonceaux, Sussex, in 1948), but its historic buildings remain a site of extraordinary significance for the history of astronomy, timekeeping and the search for the calculation of longitude. At the International Meridian Conference in Washington in 1884, Greenwich was recognised as marking the Prime Meridian, Longitude 0˚, and Greenwich Mean Time was internationally adopted. Outside the gates of the courtyard is the Shepherd 24-hour clock, erected in 1852, the year the Greenwich Time Service started sending signals. Greenwich is the official starting point of each new day. The large red Time Ball on the east turret of Flamsteed House is the world’s first visual time signal. Since 1833 it has been hoisted half-way up the mast at 12.55, to the top at 12.58, and dropped at precisely 1pm.

As visitors enter the courtyard, with Flamsteed House directly ahead and the Meridian Building on the left, a brass line in the ground marks the Prime Meridian. It runs straight through the Meridian Building, linking the North and South Poles and marking the division between the Eastern and Western Hemispheres. Visitors can thus stand astride the line, in two hemispheres at once. The Meridian is seen most dramatically at dusk when the green laser beam projected from the Observatory stretches into the evening sky, across Greenwich Hospital and the river towards the distant lights of the tall modern buildings of Canary Wharf.