.. _abs_mes_instspec:

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.