Royal Observatory, Greenwich

Royal Observatory, Greenwich. Notice the time ball atop the Octagon Room.

The Royal Observatory, Greenwich (Royal Greenwich Observatory or 'RGO') was commissioned in 1675 by King Charles II.

At this time the king also created the position of Astronomer Royal, for John Flamsteed, to serve as the director of the observatory.

He was to "apply himself with the most exact care and diligence to the rectifying of the tables of the motions of the heavens, and the places of the fixed stars, so as to find out the so much desired longitude of places for the perfecting of the art of navigation".

The Observatory is situated on a hill in Greenwich Park in Greenwich, London, overlooking the River Thames.

The Greenwich Meridian runs through the site of the Observatory. It is the line at which the longitude is defined as 0°.

Other websites

• HM Nautical Almanac Office
• The Royal Observatory, Greenwich
• Aerial View of The Royal Observatory, Greenwich at Google Maps
• The National Maritime Museum
• The RGO at Herstmonceux
• The Observatory Science Centre
• Isaac Newton Group of Telescopes