[tz] Hong Kong time 1941

Steve Allen sla at ucolick.org
Sun Nov 18 03:24:28 UTC 2018

On Sun 2018-11-18T02:58:04+0000 Joseph Myers hath writ:
> > So the scenario of the ball being dropped at 17:00 GMT daily appears to be
> > wrong - most likely the astronomer in London got a.m. and p.m. mixed up, and
> An astronomer before 1925 referring to GMT would have been using the old
> astronomical convention where the day started at noon, not midnight.


On Sat 2018-11-17T21:50:11+0000 Michael H Deckers via tz hath writ:
> The source quoted gives just an ante quem datetime for the switch. It
> suggests that the time ball regularly was dropped at 01 h local time,
> and that local time had been advanced by 00:23:18.14 h at some time
> on or before the ball was dropped on 1904-10-30. The source also
> treats the switch to UT + 08 h as a different event, the "final step"
> in the adoption of UT + 08 h in Hong Kong. On would not expect
> such a wording if the switch had happened at the same time.

According to the observations made at Hong Kong Observatory
by the folks whose clocks controlled the drop of the time ball

Meteorological Observations
made at
the HongKong Observatory
in the year 1904
page 4

the time ball is not dropped on Sundays or Government holidays, but
the log of drop times in Table 2 shows that on Sunday 1904-10-30 the
ball was dropped.  So that looks like a special case drop for the sake
of broadcasting the new local time.

Michael Deckers is probably right that the change was effective in the
middle of the night between Saturday and Sunday (but a lot of clocks
would not have been reset until observation of the usual and expected
time ball drop on Monday).

Steve Allen                    <sla at ucolick.org>              WGS-84 (GPS)
UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat  +36.99855
1156 High Street               Voice: +1 831 459 3046         Lng -122.06015
Santa Cruz, CA 95064           http://www.ucolick.org/~sla/   Hgt +250 m

More information about the tz mailing list