F 12
The ball was not raised on January 18 (10h), February 18 (10h), March 12 (10h), May 19 (10h), July 30 (16h), 31 (10h & 16h), and September 27 (10h), owing to repairs, or the prevalence of high winds.
The ball fell with an error of 0.3 sec. or less on 562 occasions, and with an error of 0.4 sec. or 0.5 sec on 76 occasions. Errors of 0.6 sec. occurred 10 times, of 0.9, 1.0 and 1.5 sec, once each. The mean probable error of the Time Ball was ± 0.18 sec. The monthly values for the past 5 years are given below:-
Probable Error of the Time Ball.
Month 1916 1917 1918 1919 1920 January ±0.15 ±0.17 ±0.11 ±0.24 ±0.17 February ±0.10 ±0.13 ±0.20 ±0.30 ±0.17 March ±0.13 ±0.17 ±0.21 ±0.12 April ±0.18 ±0.18 ±0.10 ±0.19 ±0.15 May ±0.10 ±0.17 ±0.12 ±0.14 ±0.17 June ±0.17 ±0.10 ±0.14 ±0.14 ±0.13 July ±0.10 ±0.21 ±0.11 ±0.13 ±0.22 August ±0.10 ±0.11 ±0.26 ±0.15 ±0.11 September ±0.11 ±0.10 ±0.16 ±0.10 ±0.24 October ±0.13 ±0.10 ±0.12 ±0.15 ±0.15 November ±0.13 ±0.10 ±0.12 ±0.14 ±0.19 December ±0.11 ±0.10 ±0.14 ±0.12 ±0.13 Means ±0.14 ±0.13 ±0.14 ±0.15 ±0.18Time Signals by Wireless Telegraphy.—In addition to the time signals given by the Time Ball, signals are sent at noon and at 21h. by wireless telegraphy via Cape d'Aguilar. Particulars of the programme are given in the 1918 Report. The service has been interrupted rather frequently by circumstances over which the Observatory has no control. It is to be transferred to Stonecutters when the necessary cable between this Station and the Observatory is laid.
Wireless Receiving Set.—A receiving set was installed at the Observatory by the Naval Authorities in November, and wireless Time Signals have since been regularly observed from Manila and Funabashi (Tokio), though the observations have frequently been spoilt by other stations working, in contravention of paragraph 3 of Article 45 of the Service Regulations appended to the International Radiotelegraph Convention of 1912. The Shanghai signals are still not heard.
It is hoped that the Director may soon have an opportunity of discussing details of a uniform scheme of Wireless Time Signals with the Directors of other Observatories in the Far East.
F 12
The ball was not raised on January 18 (10h), February 18 (10h), March 12 (10h), May 19 (10h), July 30 (16h), 31 (10h & 16h), and September 27 (10h), owing to repairs, or the prevalence of high winds.
The ball fell with an error of 0.3 sec. or less on 562 occasions, and with an error of 04 sec. or 0'5 sec on 76 occasions. Errors of 06 sec. occurred 10 times, of 0·9, 10 and 15 sec, once each. The mean probable error of the Time Ball was± 0·18 sec. The monthly values for the past 5 years are given below:-
Probable Error of the Time Ball.
Month,
1916
1917
1918
1919
1920
January, February,
March..
--
±0.15
±0.17
±0.11
±0.24
±0.17
*28
*10
13
'20
*30
'17
*I I
115
*12
'21
April..
*18
18
10
19
*15
May,
"10
'17
12
*14
*17
June,
*17
10
14
'14
13
July,
•10
'21
*II
13
*22
August..
*IO
"I I
*26
*15
'II
September,
11
*10
16
*10
"24
October,
*13
"10
'12
*15
15
November,
*13
'10
*12
*14
*19
December,
'II
*10
*14
*12
*13
Means,
±0.14
±0.13 ±0.14 ±0.15
+0.18
Time Signals by Wireless Telegraphy.—In addition to the time signals given by the Time Ball, signals are sent at noon and at 21h. by wireless telegraphy viâ Cape d'Aguilar. Particulars of the programme are given in the 1918 Report. The service has been interrupted rather frequently by circumstances over which the Observatory has no control. It is to be transferred to Stonecutters when the necessary cable between this Station and the Observatory is laid.
Wireless Receiving Set.-A receiving set was installed at the Observatory by the Naval Authorities in November, and wireless Time Signals have since been regularly observed from Mauila and Funabashi (Tokio), though the observations have frequently been spoilt by other stations working, in contravention of paragraph 3 of Article 45 of the Service Regulations appended to the International Radiotelegraph Convention of 1912. The Shanghai signals are still not heard.
It is hoped that the Director may soon have an opportunity of discussing details of a uniform scheme of Wireless Time Signals with the Directors of other Observatories in the Far East.
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Private notes are available after approval.