A second of arc is a unit of angular measurement equal to 1/60 of a minute of arc.
Oct 09 2016, 7:30 PM
looney_tunes
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looney_tunes Moderator 19 year member
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The use of 60ths as the division of both angular measures and time measures is based on the Babylonian sexagesimal (base-60) number system. Some applications choose to use decimal fractions of a degree (60.5 degrees, rather than 60 degrees 30 seconds).