arcminutes

Arcminutes, abbreviated arcmin or arcmin, are a unit of angular measure equal to one sixtieth of a degree. They are commonly written with a prime symbol (′) in notation. One arcminute equals 60 arcseconds and is about 0.000290888 radians (pi/10800). In practice, 1 degree comprises 60 arcminutes, and 1 radian equals about 3437.75 arcminutes.

In astronomy, arcminutes are used to express angular sizes and separations on the sky. The Moon and the Sun have apparent diameters of about 31 arcminutes. Many celestial objects, planets, and telescope fields of view are described in arcminutes, and angular resolutions of instruments are often quoted in this unit.

In geography and navigation, degrees are subdivided into arcminutes and arcseconds for latitude and longitude. One arcminute of latitude corresponds to one nautical mile along a meridian; for longitude, the ground distance of one arcminute depends on latitude and is proportional to cos(latitude), so it varies with location.

Conversions are straightforward: 1 degree = 60 arcminutes; 1 arcminute = 60 arcseconds; 1 radian = 180/pi degrees = 3437.75 arcminutes. Arcminutes are widely used in astronomy, cartography, surveying, and navigation to represent moderate angular scales and to express coordinates with finer precision than whole degrees.