Saturn with Moons Tethys and Dione . ... Credit Copyright: Voyager 1, JPL , NASA Explanation: Saturn and two of its larger moons - Tethys and Dione - were photographed by the Voyager 1 spacecraft which flew by the planet in November of 1980. This picture gives an indication of Saturn's extensive ring system , which can be seen casting a shadow on the planet, as does Tethys. Saturn 's rings are composed of many chunks of ice ranging in size from a pebble to a car. ... NASA Official: Jay Norris. ...