Saturn's rings. False colour satellite image of two density waves in Saturn's A ring. A technique called stellar occultation was used to observe the structure and dynamics of the particles that make up the ring. The brighter the region, the denser it is. The bright bands on the left have been caused by the gravitational influence of the moon Janus, while the bands on the right have been caused by the moon Pandora. This image was taken as part of the Cassini-Huygens mission, which launched in 1997 with the purpose of studying Saturn and its moons. Image taken at a distance of 6.3 million kilometres by the Ultraviolet Imaging Spectrograph (UVIS) aboard the Cassini orbiter.