A Brief History of the Apia Observatory

Excerpts from “History of the Samoan Observatory from 1902 to 1921”, by G.H. Angenheister and "Apia Observatory 1902-1977", by Jack Hoffman.

In the year 1898 the Institute for Geophysics was founded at the Georg-August University at Göttingen. Shortly afterwards the Royal Prussian Society for Sciences of Göttingen* formed a Geophysical Commission, to which were attached: geophysicist, Emil Wierchert; mathematician, Felix Klein; physicist, E Reike, Waldemar Voight, and Walter Nernst; geologist, A. von Könen; geographer, Hermann Wagner; astronomer, W. Schur. In May 1900 at the joint meeting of the four German academies in Vienna, the delegates of the KPGW put forward the proposal to operate temporary seismic stations outside Europe. Sites discussed were Palestine, Kiaochow, South America, and Samoa for the Pacific.

At the same time the German South-Polar Expedition was being prepared. At a meeting in November1899 of the Council entrusted with the preparation, the geomagnetician Adolf Schmidt had proposed that a station for recording the time variations of the Earth's magnetic field should be set up in Samoa. This station would record data over a year at the same time as the other stations set up by the South-Polar Expedition in Antarctica. On the initiative of the above-mentioned Geophysical Commission, and especially of the geographer Hermann Wagner, the KPGW produced in April 24th 1901 a memorandum entitled: "Memorandum concerning the establishment of a temporary station for the geophysical observations in Samoa."

German installation

On the 11th of June 1902, Dr Otto Tetens began construction of a number of buildings for the geophysical observatory at Mulinu'u on the island of Upolu in Western Samoa. In August 1901, Kaiser Wilhelm II of Germany had granted a sum of 30,000 marks to the University of Göttingen to establish the observatory and in December of that year Dr. Tetens was selected as Director. As usual, costs of the establishment of the observatory were greater than expected and were relieved only in June 1905 when the German Treasury granted a sum of 25,000 marks annually for five years.

Meteorological instruments and Wierchert seismographs were installed in 1902 and the magnetic instruments added in 1905. The Gauss Haus and absolute house were built in 1912 and the main office buildings in 1913. Some of these buildings function for their original purpose today. German scientists who held the position as Director during the first decade included Drs. O. Tetens, F. Linke, G. Angenheister and K. Wegener. Angenheister remained for a second term from 1912 - 1920 and despite the First World War retained the directorship of the observatory known at that time as the Samoan Observatory. Angenheister then returned to Germany where he wrote the results of his observations during his latter term.

The fields of study at this period were geomagnetism, seismology, meteorology and atmospheric electricity. A requirement of such programmes is an accurate time service. The original master clock was a Strass and Rorde which is still in operation with an accuracy of about a fifth of a second a day. Time control was carried out by transit of the sun on a Heyde transit telescope.

In July 1976 the electronic time service (Time Signal Generator) with an accuracy of about a tenth of a second a day was installed to replace the clock system. The time control is derived from signals transmitted by the stations WWNH, Honolulu.

The magnetic variometers were Eschenhagen. For measuring D and H various magnetometers were used including a Tesdorf (1921 - 1936) and CIW instruments No. 5 (before 1921) and No. 9 (1936 - 66); a Schultze (No. 2) earth inductor has been used throughout and to the present day for measuring magnetic dip. Wiechert seismographs with masses of 100 kgm in the horizontal plane and 80 kgm in the vertical plane provided the first good seismograph station in the Southern Hemisphere. The meteorological instruments were mainly of German origin except for a Robinson cup anemometer and a Campbell Stokes sunshine recorder. A Banndorf self-recording electrometer recorded the atmosphere potential gradient