Saturn's rings. Ultraviolet Cassini spacecraft image of part of Saturn's rings. It shows the outer portion of Saturn's C ring (left) and the inner portion of the B ring (right). Saturn's rings are formed of smaller ringlets containing particles ranging in size from microns to metres in diameter. Turquoise and blue colours indicate the presence of ice, whereas red shows that dirtier particles are present. This image was taken by the Ultraviolet Imaging Spectrograph instrument on the Cassini spacecraft during its entry into Saturn orbit on 30 June 2004.