It is used to get directional degree measurements (azimuth) through use of the Earth's magnetic field.
Description of Parts
A. Round Level
For accurate azimuth measurement, dip direction and trend measurements, center the bubble in the round level.
The needle is attached to a rare earth magnet which is induction damped, which allows the needle to seek magnetic north and come to a complete rest in a minimum amount of time, without accuracy degradation.
C. Graduated Circle
In combination with the needle, the 1° graduated circle allows for azimuth readings that are accurate to 1/2 degree.
D. Long Level
The long level for inclination measurement. For accurate inclination measurement, center the bubble in the long level using the vernier adjustment.
E. Rare Earth Magnet
Brunton has incorporated a cast NdFeB, rare-earth magnet which seeks magnetic north very quickly and allows for faster needle settling.
F. Zero Pin
The zero pin is the pointer used for magnetic declination adjustment. If no adjustment is necessary, the pin should point at 0° on the azimuth ring.
Unlocked: When needle locking adjustment is unlocked the needle swings freely, even when the needle release mechanism is pressed.
Locked: When needle locking adjustment is in the locked position the needle is locked in place until the needle release mechanism is pressed.
The vernier is used for inclination measurements with an accuracy to 30 minutes.