Timekeeping
Since 1885, Hong Kong Time was determined by astronomical observations at the Hong Kong Observatory using a 6-inch equatorial mount and a 3-inch Transit Circle. The time was announced to the general public, particularly mariners, by dropping a 6-feet diameter time ball from a mast exactly at 13:00 daily in front the Marine Police Headquarters Compound, where it is visible from the Victoria Harbour. In January 1908, the time ball was relocated to the hill of Blackhead Point where it had even higher visibility. With the rise of radio broadcast and the launching of Radio Hong Kong in 1922, the importance of the time ball decreased. It was decommissioned on 30 June 1933.
During the Second World War, the equatorial mount and transit circle were lost. After the war, a pendulum clock was installed and regulated by radio time signals from other timekeeping centres. Timing accuracy gradually improved from the daily engineering tolerance of a few seconds to one-fifth of a second.
In 1966, the pendulum clock in the Royal Observatory Hong Kong was replaced by a crystal oscillator timing system. In the same year, the Royal Observatory started to broadcast the time directly with a 6-pip time signal on 95 MHz. This continued until 16 September 1989.
In 1980, the Royal Observatory adopted a timing system based on a Caesium beam atomic clock. This system narrowed the engineering tolerance down to less than 1 millisecond. The frequency standard of the clock is based on the primary standard used by Japan's Communications Research Laboratory. In 1994, the atomic clock was replaced with a newer model.
Current Hong Kong Time can be obtained from the Observatory's Network Time Server.
Read more about this topic: Hong Kong Time