Ball, Robert S. (Robert Stawell), Sir, 1840-1913 · Cambridge, University press · leaf 95
80 THE CELESTIAL SPHERE [CH. IV In the mariner's compass the indications are shown on a card by the division of the circumference into 32 equal points of 11 J° … each. The four chief points on the card are marked N. (at the magnetic north), E., S., W. at intervals of 90°. Each of these intervals is bisected by points marked NE., SE., SW., NW. respectively. Thus the circumference is divided into eight equal parts of four points each. Each of these parts is…
Spherical astronomy
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