Oberon (moon) the spacecraft "Voyager 2" took several images of Oberon in January 1986, allowing 40% of the moon's surface to be mapped. Oberon was discovered by William Herschel on January 11, 1787; on the same day he discovered Uranus's largest moon, Titania. He later reported the discoveries of four more satellites, although they were subsequently revealed as spurious. For nearly fifty years following their discovery, Titania and Oberon would not be observed by any instrument other than William Herschel's, although the moon can be seen from Earth with a present-day high-end amateur telescope. All of the moons of Uranus are named
IAU definition of planet moon) might be in hydrostatic equilibrium, but would still not have been defined as a component of a double planet, since the barycenter of the system lies within the more massive celestial body (the Earth). The term "minor planet" would have been abandoned, replaced by the categories "small Solar System body" (SSSB) and a new classification of "pluton". The former would have described those objects underneath the "spherical" threshold. The latter would have been applied to those planets with highly inclined orbits, large eccentricities and an orbital period of more than 200 earth years (that is, those orbiting beyond Neptune).