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A unit of angular measurement that's equal to 1/60 of a degree. Astronomers measure separations in the sky using degrees with 180 degrees equal to the angular separation between the Northern and Southern Celestial poles.

The apparent diameter of the Sun and Moon are both approx. 0.5 degrees, which is equal to 30 arc minutes or 1800 arc seconds.

The Moon spans 0.5 degrees of apparent sky (credit:- freestarcharts)

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