F 10
The Ball is hoisted half mast at the 55th minute and full mast at the 57th minute. If the ball fails to drop at the correct time it is lowered at 5 minutes past the hour and the ordinary routine repeated at the following hour, if possible.
When the Time Ball is out of order the above routine is carried out with flag "z", on the storm signal mast.
Time Signals are also given at night by means of three white lamps mounted vertically on the Observatory radio mast. From 5h. 56m. Os. to 9h. 0m. Os. p.m. the lamps are extinguished momentarily at the even seconds, except at the 2nd, 28th, 50th, 52nd, and 54th of each minute. The hours refer to Hongkong Standard Time (8 hours East of Greenwich).
The Time Ball was dropped successfully 653 times. There were 4 failures attributable to electrical defects, or negligence on the part of the computer on duty in the tower, who was dismissed. On 4 occasions the ball was not raised owing to the prevalence of high winds. The days on which the ball failed were April 1st and 25th, September 4th and 30th. These failures occurred at 10 a.m. and in each case the fault was remedied and the ball dropped at 11 a.m.
In the following table is given the number of times different errors occurred in the years 1921 and 1922:-
Error 1921 1922 0.3 sec. or less 573 0.4 0.5 73 0.6 7 34 0.7 6 2 0.8 0.9 + 1.0 1 1.1 29 1 1.2 2 1.3 2 1.5 15 2 1.6 2 99 1.8 29 2 2.0 1 2.7 1The mean probable error of the time ball in each month for the past five years is given in the following table :-
F 10
The Ball is hoisted half mast at the 55th minute and full mast at the 57th minute. If the ball fails to drop at the correct time it is lowered at 5 minutes past the hour and the ordinary routine repeated at the following hour, if possible.
When the Time Ball is out of order the above routine is carried out with flag "z", on the storm signal mast.
Time Signals are also given at night by means of three white lamps mounted vertically on the Observatory radio mast. From Sh. 56m. Os. to 94. Om. Os. p.m. the lamps are extinguished momentarily at the even seconds, except at the 2nd, 28th, 50th, 52nd, and 54th of each minute. The hours refer to Hongkong Standard Time (8 hours East of Greenwich).
The Time Ball was dropped successfully 653 times. There were 4 failures attributable to electrical defects, or negligence on the part of the computer on duty in the tower, who was dismissed. On 4 occasions the ball was not raised owing to the prevalence of high winds. The days on which the ball failed were April 1st and 25th, September 4th and 30th. These failures occurred at 10 a.m. and in each case the fault was remedied and the ball dropped at 11 a.m.
In the following table is given the number of times different errors occurred in the years 1921 and 1922:-
Number of Times.
Error.
1921
1922
03 sec. or less
573
0'4
"7
34
0'5
73
0.6
"2
ΧΙ
I 2
633
10
6
2
0'7
6
0*8
0.9
+ ~
I
}
I'O
>>
+
I'I
29
1.3
2
"
15
2
99
1.6
2
29
1.8
2
"7
2'0
I
"
The mean probable error of the time ball in each month for the past five years is given in the following table :-
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