Why This Matters
This is important to consider, when using a compass, because your estimation can be off by the amount of degrees that should be accounted for in magnetic declination.
In America, the declination never reaches beyond 15 degrees. Check out the graphic to the left, and it will give you a better idea of some of the declination factors around the world.
Affects: Panel Orientation
Question: What's your area's degree of magnetic declination? How much does it affect system production by accounting for it?