One of New Horizons' top science goals is to make maps of Pluto and Charon, revealing details that we simply can't see from Earth. In fact, even with the best telescopes and technologies on the ground and in space, Pluto and its moons look like tiny dots of light in the sky with hardly any visible details. Here is a sampling of current Pluto system images.
This picture was taken by the Keck Telescope, Mauna Kea, Hawaii.
Note that the colors do not indicate the colors of Pluto and Charon, but the brightness of light (in the same way that contours show height on a topographic map). And because the light from Pluto and Charon is scattered by the Earth's atmosphere above the telescope, the images of Pluto and Charon are also blurred - their actual sizes are much smaller than they appear in this image.
The quality of its 8.3-meter primary mirror and the stability of the atmosphere above Mauna Kea, Hawaii, allowed the Subaru Telescope to provide clearly separated images of Pluto and Charon using its Cooled Infrared Spectrograph/Camera. This image is produced from three 2-second exposures taken through infrared filters on June 9, 1999.
Click here for more information about this image. Credit: Dale P. Cruikshank, Catherine de Bergh, Sylvain Dout, Thomas R. Geballe, Tobias C. Owen, Eric Quirico, Ted L. Roush and Bernard Schmitt; published in Science (vol. 285, p.1355), 1999.
This is the first image-based surface map of Pluto. This map was assembled by image-processing software from separate blue-light images of Pluto's disk taken with the Hubble Space Telescope. Hubble imaged nearly the entire surface as Pluto rotated in late June and early July 1994. The map, which covers 85% of the planet's surface, confirms that Pluto has a dark equatorial belt and bright polar caps. Pluto is an unusually complex object, with more large-scale contrast than any planet except Earth. Pluto itself probably shows even more contrast and perhaps sharper boundaries between light and dark areas than is shown here, but Hubble's resolution (just like early telescopic views of Mars) tends to blur edges and blend small features sitting inside larger ones.
The two smaller inset pictures at the top are actual images from Hubble. North is up. Each square pixel (picture element) is more than 100 miles across. At this resolution, Hubble discerns roughly 12 major "regions" where the surface is either bright or dark. The larger images (bottom) are from a global map constructed through computer image processing performed on the Hubble data. Opposite hemispheres of Pluto are seen in these two views. Some of the variations across Pluto's surface may be caused by topographic features such as basins, or fresh impact craters.
The picture was taken when Pluto was at a distance of 3 billion miles (roughly 5 billion kilometers) from Earth. Credit: Alan Stern (Southwest Research Institute), Marc Buie (Lowell Observatory), Larry Trafton (McDonald Observatory), NASA and the European Space Agency.
This image was constructed by combining maps of Pluto viewed through filters that select blue and green light. The colors were then increased (saturation) to make them more visible (and less realistic). Only the center of the disk has color information, and hence the grayness of the circumference.
Visit http://www.boulder.swri.edu/recent/pluto_map.html for more information on this image. Credit: Eliot Young (Southwest Research Institute), Richard Binzel (Massachusetts Institute of Technology) and Keenan Crane (Boulder High School).
Charon, smaller than Pluto, is even harder to image. Marc Buie (then of Lowell Observatory) constructed this map of light and dark areas on Charon's Pluto-facing side from mutual events of Charon by Pluto.
In July 2012, astronomers using NASA's Hubble Space Telescope reported the discovery of another moon orbiting Pluto – bringing the number of moons around Pluto to five. Estimates on the moon were 6 to 15 miles across, and in a 58,000-mile-diameter circular orbit assumed to be co-planar with the other satellites in the Pluto system.
The observations were made to help scientists plan for the July 2015 flyby of Pluto by NASA's New Horizons spacecraft.
The fifth moon, marked "P5" in this images, was named Styx. The moon marked "P4" – discovered in 2011 – was later designated as Kerberos.
Released in 2010, this is the most detailed view to date of the entire surface of Pluto, as constructed from multiple NASA Hubble Space Telescope photographs taken from 2002 to 2003. Hubble's view isn't sharp enough to see craters or mountains, if they exist on the surface, but Hubble reveals a complex-looking and variegated world with white, dark-orange, and charcoal-black terrain. The overall color is believed to be a result of ultraviolet radiation from the distant Sun breaking up methane that is present on Pluto's surface, leaving behind a dark, molasses-colored, carbon-rich residue.
The center disk (180 degrees) has a mysterious bright spot that is unusually rich in carbon monoxide frost. This region will be photographed in the highest possible detail when NASA's New Horizons probe flies by Pluto in 2015.
The Hubble images are a few pixels wide. But through a technique called dithering, multiple, slightly offset pictures can be combined through computer-image processing to synthesize a higher-resolution view than could be seen in a single exposure. This series of pictures took four years and 20 computers operating continuously and simultaneously to accomplish.