Celestial navigation glossary

Compass error

True bearing minus compass bearing: variation plus deviation.

Where the course teaches it

Compass error and deviation, in the module Checking the compass by the Sun. Find the compass error and deviation from the Sun's bearing at sunrise or sunset.

Amplitude: The Sun’s bearing from east or west as it rises or sets: a check of the compass.
Deviation: Compass error caused by the boat’s own iron and electrics; it changes with heading.