Variation (magnetic)
Charts are drawn with North towards the earth’s geographical north pole, but the Magnetic pole is not in the same place. Thus over most of the world’s surface a compass needle will point to east or west of the true pole, and the angular difference between that heading and true north is called the variation. Furthermore, the magnetic poles (North and South) do not remain in the same spots, but move slowly at a predictable rate. Fortunately the variation, and the yearly rate of change, is shown on charts, and there is no more difficulty in allowing for the difference between ‘magnetic’ and ‘true’ than there is in allowing for a watch which reads fast or slow. So don’t allow the ‘experts’ to frighten you, nor to obliterate common sense with mumbo-jumbo. Just look and see what it says on the chart. (See also: Deviation.)