4.2. Instrumentation/Specifications

INTERMAGNET recommends the use of a

• Proton Precession Magnetometer or Overhauser Magnetometer(both will be abbreviated as PPM in the following), and a

• Declination/Inclination Magnetometer (DIM, also called DI-flux, i.e. a fluxgate mounted on a theodolite).

Other combinations of instrumentation are in use for absolute determinations at some IMOs, but a new observatory should use the above pair of instruments.

Absolute instruments should be periodically compared, within an organization and internationally, for consistent operation. Bi-annual IAGA workshops offer an opportunity to make such comparisons.