This image, assembled by composites taken by the Cassini orbiter, shows Saturn and the sun in a moment of eclipse. The Cassini orbiter, part of the Cassini-Huygens mission, is a joint NASA/ESA/ASI robotic spacecraft mission sent to study Saturn and its satellites. It is made up of the orbiter and the European Space Agency-developed Huygens probe. This is named for famed Dutch astronomer Christiaan Huygens, who in 1655 became the first person to describe Saturn's rings as disks encircling the planet.