Position angle a hypothetical binary star with a PA of 135 degrees, that means an imaginary line in the eyepiece drawn from the north celestial pole to the primary (P) would be offset from the secondary (S) such that the NCP-P-S angle would be 135 degrees. When graphing visual binary orbits, the NCP line is traditionally drawn downward—that is, with north at bottom—and PA is measured counterclockwise. Also the direction of the proper motion can for example be given by its position angle. The definition of position angle is also applied to extended objects like galaxies, where it refers to the angle
Trigonometric constants expressed in real radicals number of sides). This is because the sum of the angles of any "n"-gon is 180° × ("n" – 2) and so the measure of each angle of any regular "n"-gon is 180° × ("n" – 2) ÷ "n". Thus for example the entry "45°: square" means that, with "n" = 4, 180° ÷ "n" = 45°, and the number of degrees in each angle of a square is ("n" – 2) × 45° = 90°. For cube roots of non-real numbers that appear in this table, one has to take the principal value, that is the cube root with