Co-ordinate moons
Co-ordinate moons in the broader sense are all natural satellites that move in the same or a very similar orbit around a planet .
The two Saturn moons Janus and Epimetheus are called co-ordinate moons in the narrower sense .
A subgroup of the co-orbital moons are the small Trojan moons , which move in the libration or Lagrange points of larger moons.