February 4, 2013 - 3:40am

Slowly, the old rules of navigation are changing, and one of the oldest, which dates back before the days of sailing ships, is the rule about magnetic variation and compasses: “Variation East, Magnetic Least; Variation West, Magnetic Best.” That means, for example, that if you’re flying out of Presque Isle, Maine, and want to fly due west, you need to turn onto a compass heading of 290 degrees, because up there, the local variation is 20 degrees West and the variation rule says “West is best.” That is, adding magnetic to true makes it a bigger number, or “best.” But to fly due west o