SUUNTO EON STEEL - Manual (Page 29)

Because of changes in the surrounding magnetic field, it is
recommended to re-calibrate the compass before each dive.
To manually start calibration:
1. Keep the middle button pressed to enter the menu.
2. Browse to General / Compass.
3. Press the middle button to enter Compass.
4. Scroll up or down to select Calibrate.
5. Start calibration by moving the device around in a 3D figure-8 as
the image suggests.
6. A sound indicates the calibration succeeded, and the screen goes
back to Compass menu.
NOTE: If the calibration fails several times in a row, you may be
in an area with strong sources of magnetism, such as large metal
objects. Move to another location and try to calibrate the compass
again.
3.8.2 Setting declination
You should always adjust your compass declination for the area
where you are diving to get accurate compass readings. Check the
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