User menu
Main menu

Foundations of the Royal Observatory were laid

60 second histories
by: Squaducation date: 10 Aug

The foundations of Flamsteed House, The Royal Observatory, were laid


  -  August 10th 1675  -  


In the Seventeenth Century countries and their navies were increasingly sailing the seas in search of new lands, trade, exploration and mapping.  No country wanted to be left behind.  The problem lay in the safety of the sailors and ships as navigators struggled to know exactly where they were. Although they knew how to work out latitude, once they were out of sight of land they had no idea how far east or west they were. Working out longitude was proving very troublesome.


Each 15° of longitude equated to about one hour. Determining local time from the observations of the stars and comparing it with time back home could give a sailor an idea of how far east or west he was. The trouble was that the maps of the stars, moon and planets were nowhere near accurate enough and although the pendulum clock had been invented to keep better time this timepiece was never going to work at sea.


Thus Charles II appointed a Royal Commission to look into matters astronomical. This cause was championed by Sir Jonas Moore, Surveyor-General to the King. On March 4th 1675 they reported back and recommended the building of a state-funded observatory and the appointment of an Astronomical Observator, later to be known as the Astronomer General. With extraordinary speed John Flamsteed was appointed the same day. At the time he was carrying out observations of the stars from a turret in the White Tower of the Tower of London.


Christopher Wren, who was the architect behind the re-building of St. Paul’s Cathedral after the Great Fire of 1666, suggested using the old Greenwich Castle, which was up on top of a hill, connected to a Tudor royal palace. It had solid foundations, was on high ground and was in a royal park. It was Wren who designed the new building that would house Flamsteed, his equipment and family as well as providing space for entertaining guests. The building was designed around a central octagon room that Flamsteed would use for all his kit whilst his family would live downstairs. In fact, much of what he did was done in two outbuildings in the garden called Sexton House and Quadrant House.


After building began on August 10th 1675 the building was ready by 10 July 1676 at a cost of just £520.45. The costs were kept down by recycling materials. Over time the buildings were extended to make way for new and bigger instruments. In 1818 the Royal Observatory was transferred to the control of the Admiralty and housed over 60 people working on the site. The decision to move the Observatory was taken before World War 2 due to air and light pollution and the new train lines causing vibrations and interference with magnetic observations. With the outbreak of World War 2 it stayed where it was until 1948 when it moved to Herstmonceaux Castle in Sussex. Flamsteed House was opened to the public in 1960 and, after a closure, re-opened in 2007 with state-of-the-art galleries and a new education centre.


John Flamsteed was the Royal Astronomer was 42 years. The second was Edmond Halley. Between the two of them they plotted all the stars in both the north and southern hemispheres. There have only been nine others in the 300+ years the post has existed.


Flamsteed was so wary of publishing any of his findings until he was 100% sure of his work that he refused to publish anything until he was ready. A court ordered him to publish what he had so far so he burnt many to keep them away from prying eyes.


The first public time signal was broadcast from the roof of Flamsteed House in 1833. This was done by the raising of a large ball half way up a mast at exactly 12:55. At 12:58 the ball was moved to the top of its mast and precisely at 13:00 the ball would drop alerting sea captains and ships in the various docks along the Thames to check their marine chronometers.


The problem of time keeping at sea was still a major issue and thus the ability to plot longitude was proving troublesome. At the time every town kept its own local time and standard international time was becoming essential if trade and travel was to become easier, safer and more effective. An event In 1707 brought this into even sharper focus when a fleet, commanded by Sir Cloudesley Shovel, went aground off the Scilly Isles with the loss of life of over 2000 men.  In 1714 Parliament offered the huge sum of £20,000 reward to anyone who could solve the longitude problem – and thus international time.


It was still 60 years later that John Harrison developed his H4 precision timepiece that would revolutionise time at sea. This watch was later to be immortalised in the sitcom Only Fools and Horses when Del Boy and Rodney found a Harrison ‘lesser’ watch in their lock up by accident.


In 1884 an International Meridian Conference was held in Washington DC to decide on 0° 0’ 0” so that all other world times could be taken from that point. Greenwich was chosen as the Meridian Line that marked the edge of the eastern and western hemispheres. That line is now a familiar and popular tourist attraction at the Royal Observatory.


The work of the Royal Observatory, and Flamsteed and Halley in particular, preparing their accurate charts gave British sailors an ability to navigate the seas that was far superior to any other nation on earth. It is often said that Britain rules the waves but sometimes it is forgotten that this is not only for the work of the great sailors Britain has had on the seas but also for the great work done by many off the water – much of it at the Royal Observatory, Greenwich. 

Watch our animated film to learn how you can trial our resources and over 270 films, for two whole weeks!
Watch 50+ video for free
Look for this symbol. Clock here to see all our free video NOW


Recent tweets