Determination of the Coordinated Universal Time

Hong Kong Observatory Contributes to the Determination of the Coordinated Universal Time

The Coordinated Universal Time (UTC) is the common time standard for civilian use derived from the weighted-average of the time kept by some 300 atomic clocks in over 50 national time institutes and laboratories around the world. The Bureau International des Poids et Mesures (BIPM) collects data from the participating atomic clocks, including those from the Hong Kong Observatory, and determines UTC based on an average weighted for each clock's stability. This guarantees the continuity and reliability of the world time standard that would not be affected by the breakdown or failure of one or a few highly accurate clocks.

In the first quarter of 2009, weighting of the Hong Kong Observatory's caesium beam atomic clock in the determination of UTC was up to 0.8%, a high value amongst the three hundred plus contributing atomic clocks worldwide.

Hong Kong Standard Time is UTC plus 8 hours and kept by the Observatory. Members of the public may obtain the Hong Kong Standard Time through the Observatory's network time service, Dial-a-weather System, or 6-pip time signals broadcast via Radio Television Hong Kong.

Caesium Beam Atomic Clock of the Hong Kong Observatory