From now on, 4 PTB primary atomic clocks will contribute to UTC
The world's best caesium atomic clocks control Coordinated Universal Time (UTC), an atomic time scale on which the time zones used in everyday life are based. But also in navigation (GPS), astronomy, telecommunications, geodesy and physical fundamental research, accurate timing is of essential importance. Until recently, three of PTB's clocks belonged to the exclusive club of primary caesium atomic clocks. Now a fourth one, the caesium fountain clock CSF2, has joined in. This month, its data will be taken into account for the first time for the determination of UTC. PTB and the French time-keeping institute are thus the only institutes worldwide which operate four primary atomic clocks. The traditionally large contribution of PTB's clocks to UTC has thus increased considerably...