H.—34.

DOMINION OBSERVATORY. REPORT OF THE DOMINION ASTRONOMER AND SEISMOLOGIST FOR YEAR ENDED 31st DECEMBER, 1930. Buildings and Equipment. The buildings and equipment have been kept in good order and condition. The Observatory ground has been kept in good order by the Wellington City Corporation. Astronomy. Astronomical Observations. Observations of the meridian transits of stars and the sun have been made for the purpose o f controlling the time service. The meridian transits of the sun are made on every fine day, except on Saturdays, Sundays, and Government holidays, and the stars are observed whenever necessary. Reception of Radio Time Signals at the Observatory. The following radio mean time signals were received at the Observatory:—

Scientific time signals were also received at the Observatory from Nauen on eighty-five occasions. The radio time signals received at the Observatory generally agreed with the Observatory clock within one second of time. Differences from 1 to 2 seconds, however, have been observed in the following cases : Honolulu, NPM, three times ; Nauen, DFY (mean time), once. It has not been possible to make much use of the British time signals from the Greenwich Observatory, transmitted by Rugby Radio, owing to the very unsuitable times of transmission, at 9 30 p m and 5.30 a.m., N.Z.M.T. ■ • Time Service. The time service has been maintained and the regular signals have been transmitted daily. The total number of time signals sent from the Observatory was 1,931. Of these, 461 were sent by wireless telegraph, 506 were sent by special circuit to the Telegraph-office, 362 by the signal lights at the Observatory, 100 by switching off lights at the Harbour Board building at Auckland, 95 by dropping the time-ball at Lyttelton, 20 by telephone, and 387 by wireless transmission through the Radio Broadcasting Co., Station 2YA. No radio time signals were sent on 1930, March 30, owing to no officer being on duty. On 1930, August 4, three of the signals failed owing to linesmen working between the Observatory and ZLW wireless-telegraph station. On 1930, November 11, two of the signals failed owing to an interruption in the city power-supply. The present programme at the Observatory provides for the following time signals, most of which are sent by the Observatory standard clock. The error of the standard clock is usually less than one-half second of time :— Automatic Time Signals — (1) To the General Post Office and to the Railway Department, Wellington, by telegraph, daily, except on Government holidays and on Sundays. (2) To ships and to the general public at Wellington, by electric lights at the Observatory daily. ' (3) To the Auckland Harbour Board, by electric lights at Auckland, on Tuesdays and Fridays, except Government holidays. (4) To the South Island telegraph-offices, by telegraph, on Tuesdays and Fridays, except Government holidays. (5) To the Lyttelton Harbour Board, by dropping the time-ball at Lyttelton, on Tuesdays and Fridays, except on Government holidays. (6) Radio time signals through the Radio Broadcasting Co. of New Zealand, Ltd Station 2YA, daily, at 4 h. and 8 h. G.M.T. (7) Radio time signals through the Wellington Radio Station ZLW, on Tuesday and Friday evenings at 8.30 p.m., except on Government holidays. (8) Radio time signals through the Wellington Radio Station ZLW, every day at 10 30 a m

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Station. Call Sign. Hour (G.M.T.). Number. Honolulu .. NPM (long wave) 00 264 Nauen DFY 00 283 Malabar PKX 01 53 Annapolis NSS (short wave) 03 11 Annapolis NSS (long wave) 08 8 Bordeaux .. «,. FYL 08 56 Rugby .. .. GrBR ,, 10 1 Bordeaux FYL 20 19 Total 695