F 12
Transits of the Sun were utilized occasionally.
The azimuth and collimation determinations were made by the Chief and First Assistants from observations of the old south mark. The error so obtained was checked occasionally by observations of polar stars.
Clocks. The performance of the Standard Sidereal clock conformed to no previous experience, and emphasises the necessity for a clock of more modern type, the rate of which may be depended upon during cloudy periods. During the past year cloudy periods (i.e. periods without transit observations) have, fortunately, not been prolonged.
In the following table is given the excess of the observed over the computed error after cloudy periods during 1922:-
Date 1922. Interval without observations. Excess of observed over computed error. February 13 2 days +0.09 January 4 2 +0.14 8 +0.40 15 7 +0.47 19 4 +0.06 24 5 +0.52 27 3 +0.09 March 3 +0.02 April 7 3 +0.45 12 +0.35 19 7 +0.32 21 +0.12 27 6 +0.12 31 4 +0.11 May 4 4 +0.14 7 +0.04 11 4 +0.50 19 8 +0.32 23 4 +0.00 June 3 +0.15 7 4 +0.46 21 14 +0.37 25 4 +0.36 July 4 +0.12 11 7 +0.10 14 +0.06 30 16 +0.14 August 5 +0.15 25 20 +0.25 September 6 +0.03 October November 7 26 19 December 6 21 15Page 180
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