3.3.7 Naming Pluto's other moons
In 2005, two more moons were discovered orbiting Pluto from Hubble Space Telescope images. Originally referred to as S/2005 P1 and S/2005 P2, the moons were then named in 2006 as Hydra after the nine-headed beast, to reflect Pluto’s then-status as the ‘ninth planet’ (Pluto officially lost is status as a planet in 2006), and Nix after the Greek goddess of night and mother of Charon ‘Nyx’. The spelling change from Nyx to Nix was to avoid confusion with the asteroid 3908 Nyx.In July 2011 and July 2012 two more moons were discovered, and temporarily designated S/2011 P1 and S/2012 P1 respectively. Astronomers used sets of long exposure images to prepare for the upcoming New Horizons mission by looking for any rings that Pluto might have, and discovered the two new moons.