Quick Answer
Yes, you can remember declination adjustments using a simple mental trick or by using a declination chart based on your location.
Understanding Declination
Declination is the difference between magnetic north and true north. It varies by location, and its value depends on your latitude. One degree of declination is equivalent to about 100 miles (160 km) of difference from magnetic north.
Declination Charts and Tables
Declination charts and tables are available for specific regions, making it easier to determine the declination value for your location. These charts provide declination values for the current year, and some tables include values for multiple years. For example, the US Geological Survey (USGS) provides declination tables for the United States.
The “North-South” Method
To remember declination adjustments, try using the “north-south” method. Imagine a line running from true north to your location. The declination value is the difference between magnetic north and this line. To estimate the declination value, you can use a simple mental trick: add 1 degree of declination for every 100 miles (160 km) of latitude south of 30°N, and subtract 1 degree of declination for every 100 miles (160 km) of latitude north of 60°N. This method is not precise but provides a rough estimate and can be helpful in emergency situations when a more accurate declination chart is not available.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.