NASA image collected 2012-07 from an orbiting telescope showing the entire planetoid system. The two central objects are Pluto and Charon, the smaller objects are 2 of 4 small planetoids.
The 4 planetoids orbiting Pluto and Charon are Hydra, Nix, Kerberos, and Styx:
"New Horizons probe sees Charon orbiting Pluto", 2014-08-07 by Clark Lindsey with "Space-for-All at HobbySpace" [http://hobbyspace.com/Blog/?p=8506]:
The New Horizons spacecraft is steadily closing in on Pluto as it heads for a fly-by next July. The spacecraft can now distinguish Pluto from its moon Charon with its long range camera.
Visit New Horizons online at [http://pluto.jhuapl.edu/index.php].
(Pluto and Charon dance in this sequence of images taken over 6 days)
Like explorers of old peering through a shipboard telescope for a faint glimpse of their destination, NASA’s New Horizons spacecraft is taking a distant look at the Pluto system – in preparation for its historic encounter with the planet and its moons next summer.
“Filmed” with New Horizons’ best onboard telescope – the Long Range Reconnaissance Imager (LORRI) – this movie covers Pluto and almost one full rotation of its largest moon, Charon. The 12 images that make up the movie were taken July 19-24, from a distance ranging from about 267 million to 262 million miles (429 million to 422 million kilometers). Charon is orbiting approximately 11,200 miles (about 18,000 kilometers) above Pluto’s surface.
New Horizons snapped this image sequence as part of the mission’s first optical navigation campaign. The mission team uses these “op nav” images – which focus on Pluto’s position against a backdrop of stars – to fine-tune the distance that New Horizons will fly past Pluto and its moons. New Horizons is aiming for a precise close-approach point near Pluto in July 2015, so these and images to come – which help navigators and mission designers to get a better fix on Pluto’s position – are critical to planning the encounter operations.
Pluto’s four smaller satellites (Nix, Hydra, Styx and Kerberos) are too faint to be seen in these distant images, but will begin to appear in images taken next year as the spacecraft speeds closer to its target.
“The image sequence showing Charon revolving around Pluto set a record for close range imaging of Pluto—they were taken from 10 times closer to the planet than the Earth is,” says New Horizons mission Principal Investigator Alan Stern, of the Southwest Research Institute, Boulder, Colo. “But we’ll smash that record again and again, starting in January, as approach operations begin.
“We are really excited to see our target and its biggest satellite in motion from our own perch,” he adds, “less than a year from the historic encounter ahead!”
As August begins, New Horizons is near the end of its final pre-Pluto annual systems checkout and instrument calibration before Pluto arrival. The New Horizons mission operations team at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, will put the spacecraft back into hibernation on August 29 – just four days after New Horizons crosses the orbit of Neptune on August 25.
That final “rest” lasts only until December 6, when New Horizons will stay wake for two years of Pluto encounter preparations, flyby operations, and data downlinks. Distant-encounter operations begin January 4, 2015.
"Pluto's moons not named Vulcan", 2013-07-03 by David Perlman from "San Francisco Chronicle" [www.sfchronicle.com/science/article/Pluto-s-moons-not-named-Vulcan-4643968.php]:
Two characters from Greek mythology now have their names on two moons of the dwarf planet Pluto following a global election set up by the man who discovered the moons, a senior research scientist at the SETI Institute in Mountain View.
The names - Kerberos and Styx, after a dog and a river - were announced Tuesday by the International Astronomical Union, arbiter of all astronomical names.
It was the first crowdsourced election in the history of astronomy, and ballots came in from 30,000 voters around the world, said Mark Showalter, the researcher who discovered the tiny moons on a search through Hubble Space Telescope images.
An additional 450,000 ballots that voters e-mailed in were rejected because they ignored the rules and proposed random names like Mickey and Minnie, Showalter said.
Actor William Shatner, who played Capt. Kirk on "Star Trek," submitted the name Vulcan, but it, too, was rejected even though Showalter favored it, he said.
The astronomy governing body's rules require that the new names of the two moons, known until now as P4 and P5, had to come from classical mythology, "particularly with reference to the underworld." Pluto was the god of that much-feared realm.
Thus Kerberos - better known to most amateurs as Cerberus" - was the three-headed dog that guarded the gates of Hades, and Styx was the river that all doomed passengers had to cross to get there.
Rather than proposing names to the International Astronomical Union, Showalter and his colleagues set up a website open to the public and proposed 21 Greek underworld names. Voting ended in February, and the voters chose Vulcan first, with Cerberus and Styx next.
Vulcan, the astronomical union announcement said, had already been used for a hypothetical planet between Mercury and the sun, although that planet was ultimately found not to exist.
Showalter is on the science team of NASA's New Horizons spacecraft now headed for Pluto and its five known moons.
It was launched in 2006 and is scheduled to fly past the dwarf planet in 2015 after a 3-billion-mile flight. Showalter is using the Hubble telescope's findings to hunt for icy particles in Pluto's region that might threaten the New Horizons spacecraft. And he is looking for new discoveries.
"And there may be six or seven or even eight more new planets around there, still to be found," he said Tuesday.
