Moons are classed into two separate classes according to their orbits: frequent moons, which have prograde orbits (they orbit inside the direction of their planets' rotation) and lie near the airplane of their equators, and irregular moons, whose orbits might be pro- or retrograde (from the direction in their planets' https://bestmoons16048.blogpixi.com/34971878/bestmoons-no-further-a-mystery