The Dawn spacecraft took this picture of the dwarf planet Ceres, the largest body in the main asteroid belt, on 1 December. It was about 1.2 million km away. Dawn will be captured into Ceres’ orbit in March. That will be the first visit to a dwarf planet by a spacecraft. Later in 2015, New Horizons will fly by the dwarf planet Pluto.
Dawn has already visited Vesta, a giant protoplanet currently located 168 million km from Ceres. That’s greater than the distance between the Earth and the sun. During its 14 months in orbit around Vesta, the spacecraft sent back images of its cratered surface and science data containing important clues about its geological history. Vesta and Ceres are the two most massive bodies in the main asteroid belt. Ceres has a mean diameter of about 950 km.
The nine-pixel-wide image of Ceres released today serves as a final calibration of the science camera that is necessary before Dawn arrives at Ceres. At the current range between the spacecraft and the dwarf planet, it appears approximately as bright as Venus sometimes appears from Earth.