Friday, August 17, 2012

Arc Minute - Definition

Arc Minute

An angular measurement equal to 1/60th of a degree.

A minute of arc, arcminute, or minute arc (MOA), is a unit of angular measurement equal to one sixtieth (160) of one degree(circle21,600), or (π10,800) radians. In turn, a second of arc or arcsecond is one sixtieth (160) of one minute of arc. Since one degree is defined as one three hundred and sixtieth (1360) of a rotation, one minute of arc is 121,600 of a rotation. It is used in those fields which require a unit for the expression of small angles, such as astronomy, navigation and marksmanship.
The number of square arcminutes in a complete sphere is

or approximately 148,510,660.498 square arcminutes.

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