Which term describes the angular difference between true north and magnetic north?

Which term describes the angular difference between true north and magnetic north?

• A. The angular difference between magnetic north and east
• B. The angle between the ship's heading and magnetic north
• C. The tilt of the compass housing
• D. The angular difference between true and magnetic north

Answer: (D)

Magnetic declination is the angle between true north and magnetic north. This measurement tells you how far a compass (which points to magnetic north) is off from geographic north, and it varies by location and over time. In practice, navigation charts show the current declination for a given area, so you can convert a true course to a magnetic course by applying it: if the declination is east, subtract it from the true course; if it’s west, add it. For example, a declination of 8° east means a true heading of 60° would be read as 52° on a magnetic compass. The other options describe related concepts that aren’t the term for this angular difference.

Magnetic declination is the angle between true north and magnetic north. This measurement tells you how far a compass (which points to magnetic north) is off from geographic north, and it varies by location and over time. In practice, navigation charts show the current declination for a given area, so you can convert a true course to a magnetic course by applying it: if the declination is east, subtract it from the true course; if it’s west, add it. For example, a declination of 8° east means a true heading of 60° would be read as 52° on a magnetic compass. The other options describe related concepts that aren’t the term for this angular difference.