their associated instruments (directors or aiming circles), their elevation sights (clinometers or quadrants), together with their manual plotting devices, firing tables and fire control computers. Artillery spotters typically use their calibrated binoculars to move fired projectiles' impact onto a target. Here they know the approximate range to the target and so can read off the angle (+ quick calculation) to give the left/right corrections in meters. A mil is a meter at a range of one thousand meters (for example, to move the impact of an artillery round 100 meters by a gun firing from 3 km away, it is necessary to shift the direction by 100/3 = 33.3 mils.) Other scientific and technological uses The milliradian (and other SI multiples) is also used in other fields of science and technology for describing small angles, i.e. measuring alignment, collimation, and beam divergence in optics, and accelerometers and gyroscopes in inertial navigation systems. See also Scandinavian mile, a unit of length common in Norway and Sweden, but not Denmark, today standardised as 10 kilometers. Thousandth of an inch, an inch-based unit often called a thou or a mil. Circular mil, a unit of area, equal to the area of a circle with a diameter of one thousandth of an inch. Square mil, a unit of area, equal to the area of a square with sides of length of one thousandth of an inch. Footnotes References External links Units of plane angle Decimalisation