Pluto

Discoverer: Clyde Tombaugh (18 Feb. 1930)

MAJOR MOON (Diameter)

Charon (1,207 km) discovered by J. Christy 1978.

Minor Moons:

Nix & Hydra & newly discovered P4

Details of rise and set as well as relevant monthly information can be found on the Sky This Month page.

Pluto never grows beyond a faint star like point in the telescope and can be identified by its slow movement amongst the background stars over a period of a week or so.

Videos:

Pluto the Un-Planet. Since its discovery in 1930, Pluto has always occupied a special place in our hearts as the ninth planet in the Solar System. But recent discoveries of new objects in the Sun's neighbourhood have called into question the definition of a planet. In 2006, the International Astronomical Union established new criteria to define planets and, sadly, Pluto no longer ranked with the big boys. Instead, it was reclassified a dwarf planet, which sparked heated debates and protests among those striving to restore Pluto's "planet-hood."

NEWS:

NASA's Hubble Discovers Another Moon Around Pluto - 20 July, 2011

Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy dwarf planet Pluto. The tiny, new satellite – temporarily designated P4 -- was uncovered in a Hubble survey searching for rings around the dwarf planet. The new moon is the smallest discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter (32 to 113 km). Image credit: NASA, ESA, and A. Feild (STScI)

SPACECRAFT MISSION:

New Horizons - New Horizons launched at 19:00 UT (2:00 p.m. EST) on 19 January 2006 on an Atlas V 551 booster with a Star 48B third stage directly into an interplanetary trajectory. It passed within 101,867 km of main belt asteroid JF56 on 13 June 2006. It used the encounter as a test of its instruments and tracking and navigation sensors, and returned images of the 2.5 km diameter asteroid, which only shows as a faint dot at that distance. It reached Jupiter for a gravity assist on 28 February 2007. The flyby came within about 32 Jovian radii of Jupiter at 21 km/s and was the center of a 4 month intensive Jupiter system observation campaign.

The flyby put the spacecraft on a trajectory towards Pluto, about 2.5 degrees out of the plane of the solar system. On 8 June 2008 New Horizons crossed the orbit of Saturn. During cruise to Pluto New Horizons may be targeted to fly by a Centaur object (an escaped Kuiper Belt Body) if a suitable target can be identified. Flyby of Pluto will occur nominally on 14 July 2015. The encounter period begins 6 months prior to closest approach.

(NASA)