Outermost of the four large moons (Galilean satellites) discovered around Jupiter by the Italian astronomer Galileo in 1610. It was probably also discovered independently that same year by the German astronomer Simon Marius, who named it after Callisto of Greek mythology. Callisto is a dark, heavily cratered body of rock and ice that appears to have remained substantially unaltered inside and out for the past four billion years.
Full Moon
Spring
Hunter 
Hunter