1 degree = 60 arcminutes, 1 arcminute = 60 arcseconds One arcminute is about the resolution of the human eye. That is, if two points are less than 1 arcminute

1 degree = 60 arcminutes, 1 arcminute = 60 arcseconds One arcminute is about the resolution of the human eye. That is, if two points are less than 1 arcminute apart on the your field of view, they appear as one point. The moon is 30 arc minutes (1/2 degree) on your field of view, that's why one can see the details of the surface with the naked eye. 18 arcseconds is about the size of Saturn (without the rings) as seen from the earth. It means it is just precise enough to shoot through the rings of Saturn. You can't see this without magnification, like with a small telescope or a good pair of binoculars.