Question

what is an arc second?​

Answer 1

Answer:

The minute of arc is a unit of angle equal to 1/60th of one degree, or 1/21,600 of a circle. The minute of arc is also equal to π/10,800 radians. A minute of arc is sometimes also referred to as an arc minute, arcminute, or minute arc.

Answer 2

Answer:

An arcsecond (denoted by the symbol “) is an anglular measurement equal to 1/3600 of a degree or 1/60 of an arcminute. There are also 206,264.5” in a radian, so that 1” = 4.848 ×10-6 radians. A milliarcsecond is 10-3 arcseconds. A microarcsecond (μas) is 10-6 arcseconds.