1. What is Magnetic Declination?

Magnetic declination is the angle between magnetic north (the direction the compass needle points) and true north. This angle varies depending on your location on Earth and changes over time.

2. How Does the Calculator Work?

The calculator uses the NOAA declination equation:

Where:

• \( Y \) — Magnetic field Y component (nT)
• \( X \) — Magnetic field X component (nT)
• \( decl \) — Declination angle in degrees

Explanation: The equation calculates the angle whose tangent is the ratio of the Y component to the X component of the Earth's magnetic field.

3. Importance of Magnetic Declination

Details: Accurate declination values are crucial for navigation, surveying, and any application requiring precise orientation. Without accounting for declination, compass readings can be significantly off from true north.

4. Using the Calculator

Tips: Enter the X and Y components of the magnetic field in nanoteslas (nT). The X component cannot be zero as this would result in division by zero.

5. Frequently Asked Questions (FAQ)

Q1: Why does magnetic declination vary by location?
A: The Earth's magnetic field is not uniform and varies due to differences in the core's structure and local geological features.

Q2: How often does magnetic declination change?
A: Declination changes gradually over time as the Earth's magnetic field evolves. NOAA updates declination values every 5 years.

Q3: What's the difference between declination and inclination?
A: Declination is the horizontal angle between magnetic and true north, while inclination is the vertical angle the field makes with the surface.

Q4: Are there limitations to this calculation?
A: This is a simplified calculation. For precise navigation, you should use location-specific declination values from NOAA's models.

Q5: How does this relate to compass navigation?
A: To find true north with a compass, you must add or subtract the declination angle depending on whether it's east or west declination.