Observations in Dourbes

For many practical and scientific purposes, Belgium needs continuous knowledge of the changing geomagnetic field. This is the case, for example, for the magnetic declination which is used to find the North with a compass. Therefore, observations are carried out in the Magnetic Observatory at Dourbes (photo) and Manhay. Measurements of the complete geomagnetic vector are performed and stored every minute.

The magnetic observatory in Dourbes

The main activities are:

In addition to observations in observatories, observations are also regularly made on the entire Belgian territory. On request, it is also observed abroad. Only SI units are used and our best accuracy is 0.1 nT for the magnetic induction and 0.001 ° for angle measurements. The Observatory in Dourbes has a workshop for geomagnetic instruments. We design, manufacture, test and calibrate small series of geomagnetometers: optically pumped and proton magnetometers, fluxgate and DIDD variometers, (automatic) Difluxes and North Seekers.

Our magnetically uninfected environment in Dourbes allows the testing of amagnetism for components of industry and science.


The main products are:

Time series of the geomagnetic field is the most important output. These are published in yearbooks and are stored in the RMI and the international databases. Time series are also available online in near real-time via the INTERMAGNET network. Another product is the magnetic activity index.

Tijdreeksen van het geomagnetische veld is de belangrijkste output. Deze zijn uitgegeven in jaarboeken en zijn opgeslagen in de KMI en internationale databanken. Tijdreeksen zijn ook online beschikbaar in quasi real-time via het INTERMAGNET netwerk. Een ander produkt is het magnetisch activiteit index.

The following products are available:

  • Magnetic declination
  • value of the sekular change of the magnetic covering for given times and/or places
  • magnetic maps

The following services can be granted:

  • In-situ observations of the magnetic declination or other components
  • Calibration and testing from compasses and gyrotheodolits
  • setting up and certifying the compass rose at airports and measuring their magnetic azimuth


Observatoire Magnétique

2, Rue du Centre de Physique, Dourbes
B-5670 Viroinval, België

Dr. Simo Spassov (FR-DU-GE), Head of the Scientific Service
Tel.: 0032 (0)60 39 54 98
E-mail: Simo.Spassov[at]

Jean-Luc Marin (FR)
Tel : +32(0)60 395420
E-Mail : jean-luc.marin[at]

Magda Francotte (FR), Secretariat
Tel : +32 (0)60/395411
E-Mail : magda.francotte[at]


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