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Saturday, December 29, 1973
ON-SECOND TIME ADJUSTMENT IN HONG KONG TIME
The usual six-pip time signals from the Royal Observatory will
not be broadcast at 9 a.m. on Tuesday (January 1) but will be resumed
at 9.15 a.a. that day, a Royal Observatory spokesman said today.
This is to enable a correction to be applied which will result
in an apparent delay of one second to the resumed time service signals,
he explained.
The need to set the clocks back by one second arises because
world-wide time standards are now based on the atomic time scale.
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"This provides a more precise and uniform second than that derived
from the rate of rotation of the earth measured by astronomical means,
the spokesman said.
Hong Kong's time service has been maintained by reference to the
atomic time scale since January 1, 1972.
The spokesman said that one day on the astronomical time scale
is, on the average, three-thousandths of a second longer than the day
on the atomic time scale.
"However, it has been internationally agreed that the two times
should never differ significantly and that periodic adjustments of the
whole second would be made to the time shown by those clocks using or being
maintained by reference to the atomic time scale. By the end of December,
the difference will be almost four-tenths of a second."
The correction of one second, called a leap-second, is analogous
to February 29 in a leap year with which everyone is
familiar,
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