**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 (

^{1}⁄_{60}) of one degree(^{circle}⁄_{21,600}), or (^{π}⁄_{10,800}) radians. In turn, a second of arc or arcsecond is one sixtieth (^{1}⁄_{60}) of one minute of arc. Since one degree is defined as one three hundred and sixtieth (^{1}⁄_{360}) of a rotation, one minute of arc is^{1}⁄_{21,600}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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