1. What Is Magnetic Deviation?

Magnetic deviation is the angle between the compass bearing and the magnetic bearing caused by local magnetic fields in the vessel or aircraft. It differs from magnetic declination, which is the angle between magnetic north and true north.

2. How To Calculate Magnetic Deviation

The calculator uses the deviation formula:

Where:

• \( Compass\ Bearing \) — The direction shown by the compass (degrees)
• \( Magnetic\ Bearing \) — The actual magnetic direction (degrees)

Explanation: Positive deviation means the compass points east of magnetic north, while negative deviation means it points west.

3. Importance of Deviation Calculation

Details: Accurate deviation calculation is crucial for navigation, especially in aviation and marine applications where precise heading is essential for safety.

4. Using the Calculator

Tips: Enter both bearings in degrees (0-360). The calculator will compute the deviation and normalize it to the range of -180 to +180 degrees.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between deviation and declination?
A: Deviation is caused by local magnetic fields, while declination is the angle between magnetic and true north that varies by location.

Q2: How often should deviation be checked?
A: In aviation, compass deviation should be checked during annual inspections or whenever equipment is added/removed near the compass.

Q3: What causes magnetic deviation?
A: Local magnetic fields from electrical equipment, metal structures, or ferrous materials near the compass.

Q4: How is deviation typically corrected?
A: Through compass compensation (adjusting small magnets near the compass) and by creating a deviation card for residual errors.

Q5: What's considered a significant deviation?
A: Generally, deviations greater than 3-5 degrees may require compensation or correction in critical navigation applications.