History of Geomagnetic Observation

At SGO the first instrument to measure the magnetic field was the "Eschenhagen" type variometer, made by O. Töpfer and modified by Ad. Schmidt, both in Potsdam. This instrument, also called "Töpfer", was in use until the end of 1935. The main instrument from 1936 to 1986 was the well-known Danish variometer "La Cour". From 1986 to 2003 the main instrument of SGO was a Polish photoelectric torsion magnetometer (PSM). Today our main instrument is the Danish fluxgate magnetometer (FG). As backup magnetometer we currently use PSM and a Russian photoelecric torsion magnetometer (RM). For testing and calibration the "La Cour" was in use already since 1931, PSM since 1983, FG since 1996 and RM since 1996. For absolute measurements SGO used a "Wild-Edelmann" theodolite in 1914 and since 1915 a "Schulze" theodolite to measure the magnetic declination and the horizontal intensity. SGO had the Earth inductor "Schulze" no. 104 and the galvanometer "Schulze" no. 111 to measure the magnetic vertical intensity.

In 1952 SGO got three well-known Quartz Horizontal Magnetometers (QHM) nos 116, 117 and 118. In order to measure the vertical intensity, SGO got a new instrument BMZ (Balance

Magnetomêtrique Zero) no. 31 in 1952 and no. 227 in 1959. For total intensity measurements we got the proton precession magnetometer "Elsec" type 592 no. 226 in 1965 and the proton precession magnetometer "Elsec" type 770 and "Helmholz" coil system in 1984. To measure the magnetic declination SGO got an Askania declinometer and Askania theodolite in 1965. Since 1965 the Askania theodolite was used also instead of the "Schulze" theodolite.
In 1984 the observatory took a completely new instrument into use, namely the fluxgate magnetometer "DI-flux", "Elsec 810" to measure the magnetic declination and inclination. From 1992 all absolute measurements were done using only the DI-flux and proton precession magnetometer, which, in 2001, was replaced by a Canadian Overhauser magnetometer GSM-90. For field compaigns we got a "Hungarian" theodolite with Danish electronics in 2001. In our observatory there have been several magnetometers in operation at different times, e.g. the "quick-run magnetometer La Cour" 1931-1983.
Analog measurements ended at the end of 1995.

The Helmholz coil and the proton precession

magnetometer in the Absolute room, where the magnetic

field is measured once per week.

Last updated: 26.10.2016