Quick Answer
Declination affects navigation skills by causing the magnetic needle of a compass to deviate from true north, leading to inaccurate readings and potentially hazardous decisions. This deviation can vary significantly depending on location and time of year. Failure to account for declination can result in up to 20 miles of error over a 24-hour period.
Understanding Declination
Declination is the difference between magnetic north and true north, which can vary from 0 to 20 degrees. The declination value is influenced by the Earth’s magnetic field and can change over time due to the movement of the Earth’s magnetic poles. In some areas, declination can be as high as 20 degrees, while in others it may be less than 1 degree.
Calculating Declination
To calculate declination, you can use an online declination calculator or a declination chart specific to your location. If you’re in an area with a significant declination, it’s essential to adjust your compass readings accordingly. For example, if the declination is 10 degrees east, you’ll need to add 10 degrees to your compass reading to get the correct bearing.
Adjusting Compass Readings
To adjust for declination, you’ll need to add or subtract the declination value from your compass reading. For example, if your compass indicates a bearing of 270 degrees and the declination is 10 degrees east, you’ll need to add 10 degrees to get the correct bearing. This would be 280 degrees. It’s essential to remember that declination can vary depending on your location and time of year, so it’s crucial to stay up-to-date with the latest declination values.
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