There are 60 minutes (denoted as 60') of arc in 1 degree. In the sky, with an unobstructed horizon (as on the ocean), one can see about 180 degrees of sky at once, and there are 90 degrees from the true horizon to the zenith. The full moon is about 30' (30 arc minutes) across, or half a degree. There are 60 seconds (denoted 60") of arc in one minute of arc.