Time/clocks
Greenwich is where the world's time is measured from (base time zone for the world). The Royal Observatory has a device, the time ball, that could be seen from the Thames so the ships could set their clocks.
Greenwich Mean Time is what the time differences for all around the world are worked out from.
The Royal Observatory is the home of Greenwich Mean Time, the Prime Meridian of the World, London's only planetarium, the Harrison timekeepers and the UK's largest refracting telescope.
Greenwich Mean Time is what the time differences for all around the world are worked out from.
The Royal Observatory is the home of Greenwich Mean Time, the Prime Meridian of the World, London's only planetarium, the Harrison timekeepers and the UK's largest refracting telescope.
THE royal observatory
The Observatory was set up in Greenwich by Charles II in 1675 and built by Christopher Wren. He was short of money at the time, so he chose land in his Royal Park in Greenwich and used recycled bricks and timber.
In the 17th century, sailors at sea could work out their latitude (how far north or south they were), but couldn't work out their longitude (how far east or west they were). As a result, many ships got lost. Some of these then sank or ran out of supplies. Scientists believed that sailors would be able to work out their longitude by observing the position of the stars and the moon. To do this, they needed to know where the stars and moon were going to be at different times. King Charles had the Observatory built to provide this information.
In 1852, the Observatory had its own special clock installed, the Shepherd master clock. This was connected to a slave clock installed at the gates to the Observatory and was the first clock ever to show Greenwich Mean Time (GMT) directly to the public. People would bring their clocks or watches to Greenwich and check them, and in turn used their clock or watch to check those of other people. The Observatory gate clock is still there for us to use today.
Before the gate clock, the only way the public could check the time at Greenwich was by using the time ball.
In the 17th century, sailors at sea could work out their latitude (how far north or south they were), but couldn't work out their longitude (how far east or west they were). As a result, many ships got lost. Some of these then sank or ran out of supplies. Scientists believed that sailors would be able to work out their longitude by observing the position of the stars and the moon. To do this, they needed to know where the stars and moon were going to be at different times. King Charles had the Observatory built to provide this information.
In 1852, the Observatory had its own special clock installed, the Shepherd master clock. This was connected to a slave clock installed at the gates to the Observatory and was the first clock ever to show Greenwich Mean Time (GMT) directly to the public. People would bring their clocks or watches to Greenwich and check them, and in turn used their clock or watch to check those of other people. The Observatory gate clock is still there for us to use today.
Before the gate clock, the only way the public could check the time at Greenwich was by using the time ball.
the time ball
The bright red Time Ball on top of Flamsteed House is one of the world's earliest public time signals, distributing time to ships on the Thames and many Londoners. It was first used in 1833 and still operates today.
Each day, at 12.55, the time ball rises half way up its mast. At 12.58 it rises all the way to the top. At 13.00 exactly, the ball falls, and so provides a signal to anyone who happens to be looking. Of course, if you were looking the wrong way, you had to wait until the next day before it happened again.
The Time Ball drops at 13.00 GMT during the winter months and 13.00 BST during the summer.
Each day, at 12.55, the time ball rises half way up its mast. At 12.58 it rises all the way to the top. At 13.00 exactly, the ball falls, and so provides a signal to anyone who happens to be looking. Of course, if you were looking the wrong way, you had to wait until the next day before it happened again.
The Time Ball drops at 13.00 GMT during the winter months and 13.00 BST during the summer.