🔍 Key Concepts

• True heading vs. magnetic heading vs. compass heading • The definitions of variation and deviation • How compass error is related to variation and deviation

💭 Think About

• Start from true and think about what natural, charted influence changes it before you even touch the ship’s compass. • Ask yourself: which term is printed on the compass rose of a nautical chart and shows the relationship between true north and magnetic north? • Consider which term depends on the ship’s own magnetic fields and which term exists everywhere on earth, even without a vessel.

✅ Before You Answer

• Be clear which norths you are comparing: true north vs. magnetic north, not compass north. • Verify which quantity is shown as degrees East or West on the outer/inner scale of the compass rose on charts. • Confirm that deviation is specific to each vessel and heading, while the other quantity is a property of the earth’s magnetic field in that area.