On the 75th anniversary of the first broadcast of the six-pip Greenwich Time Signal by the BBC, the Royal Observatory displayed for the first time in public, the time pieces which produced the six pips for their first broadcast in 1924. The 1874 Dent regulators have recently returned to Greenwich following the closure of the Royal Greenwich Observatory at Cambridge.
The six-pip Time Signal was introduced following the successful broadcast of the chimes of Big Ben to usher in the New Year of 1924. Late in 1923, Frank Dyson, ninth Astronomer Royal, visited John Reith, Director General of the BBC, to discuss the idea of public time signals being broadcast. The six-pip Time Signal (pips for seconds 55,56,57,58,59,00) was Dyson's brainchild, devised in discussion with Frank Hope-Jones, inventor of the free pendulum clock, who had originally advocated a five-pip signal. The sixth pip signals the start of the next minute.
In 1939, the six pip signal and the Time Service moved from Greenwich to the magnetic observatory at Abinger in Surrey. They then moved to Herstmonceux, Sussex in 1957. In 1990, the Greenwich Time Service transmitted its last pips. Since then the BBC has originated its own pips based on signals from the GPS satellite network and from the 60kHz radio transmitter at Rugby, operated by BT Aeronautical and Maritime under contract to the National Physical Laboratory.
Jonathan Betts, Curator of Horology at the Royal Observatory, said "It is entirely fitting that we display the timepieces which spread GMT and the famous 'pips' across the world at a point in history when time is on everyone's minds. We are pleased to give recognition to the work of Sir Frank Dyson and to commemorate the historic link between the Observatory and the BBC."