Freezing time

25 Mar 2013

The Greenwich Time Ball has been a popular attraction for visitors to Greenwich Park and the Royal Observatory since its construction in 1833. It was built to broadcast a daily one o’clock time signal to mariners on the river and in the docks so that they could check the rate of their chronometers before heading out to sea.

Since its installation there have only been a few brief periods during which the ball has not operated. Perhaps the most dramatic of all was in late 1855 when the ball and mast were blown down from the roof after ingress of rainwater had rotted the base of the mast.

Unfortunately, due to recent bad weather the mast has iced up and this prevents us from operating the ball. The build-up of snow and ice in the channel that guides the ball can be seen in the photograph below.

Snow and ice prevent the Greenwich time ball from being raised, March 2013

Writing in The Observatory in 1958, P.S. Laurie recalled that when the ball became iced up ‘the expectant public was on rare occasions treated to the sight of the unfortunate Assistant in Charge (or, probably, more expendable material, such as a supernumerary computer) attempting to scale the mast.’

Fortunately for staff at the Royal Observatory today, lives at sea are protected by modern technology and so we will not have to send anyone up to shift the ice.