Minute of arc
The minute of arc or arcminute or minute (from the Latin pars minuta, scaled- part ') is one sixtieth of a degree angle. It represents a subdivision of the unit level to specify the size of plane angle dar.
The full angle has 360 degrees. A degree consists of 60 minutes of angle: 1 ° = 60 '. A minute of angle corresponds thus
A minute of angle turn, consists of 60 seconds of arc: 1 ' = 60 "; which means: 1 ° = 3600 ". As Dezimalminute refers to an indication of the minutes with decimals instead of angular seconds.
It should be noted that ( according to this definition ) indication of size in minutes of arc despite having the same prefix " arch " has nothing to do with an indication in radians. Do not confuse the units of angle minute and second are, moreover, with the indication of right ascension in hours, minutes and seconds in the time scale of astronomy.
The minute of angle does not belong to the International System of Units ( SI), but is approved for use with the SI. This is a legal unit.
In analogy to the usual specification of times, angles in a notation that the degrees, minutes, and seconds are used together, indicated. To the imaging angle is represented as a sum of three positions, wherein the numerical values are in front of the minutes and seconds is less than 60. This notation is used for example in geographical coordinates for specifying longitude and latitude. 51 ° 14 ' 4.2 " is the notation for 51 degree angle 14 minutes 4.2 seconds of arc.
The unit symbol for the minute of angle consists of a straight, inclined, superscript bar: 1 ' = 1 minute. The typographically correct character in Unicode is PRIME, U 2032 code. Alternatively, a vertical bar ( ') is used. On a typewriter or PC one often uses the apostrophe. The unit symbol is immediately after the last digit of the numerical value written without gap as with the symbols of the units of angle degrees and seconds. See also degree sign.
The latter notation is used in the following example: 51 ° 14 ' 4.2 " (read: 51 degrees, 14 minutes, 4.2 seconds) are as follows convert to decimal notation:
The conversion from decimal degrees to degrees - minutes-seconds is done by the decimal is first multiplied by 60.
The resulting integer are the angular minutes. The remaining decimal is again multiplied by 60.
The resulting number is the seconds.
- A minute angle corresponds roughly to the angle at which appears the diameter of a circle of one meter at a distance of 3440 m.
- As a size comparison for a minute of angle and the moon can be used. For an observer on Earth, the entire diameter of the moon in the middle extends over an angular range of about 31 arcmin.
- On the surface one minute of arc of a great circle earth is approximately 1852 m. From the nautical mile is derived.
- At 100 meters a minute of arc corresponds to about 2.91 cm. The unit angular minute ( engl. MOA ) is used in ballistics, among others for precision details of cluster circles.