This is Cassini's best look yet at the Trojan moon Telesto (24 kilometers, or 15 miles across), which orbits Saturn about 60 degrees ahead of the much larger Tethys (1,071 kilometers, or 665 miles across). Calypso (22 kilometers, or 14 miles across, and not seen here) is the other Tethys Trojan, and trails the larger moon by 60 degrees. Trojan moons are found near gravitationally stable points ahead or behind a larger moon.
Cassini is able to partly resolve Telesto's shape in this view, but surface features are too small to be visible from this distance.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2005, at a distance of approximately 533,000 kilometers (331,000 miles) from Telesto. The image scale is 3 kilometers (2 miles) per pixel. This view of Telesto has been magnified by a factor of three and sharpened to aid visibility.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.
Credit: NASA/JPL/Space Science Institute