This movie shows a bright arc of material flashing around the edge of Saturn's G ring, a tenuous ring outside the main ring system.
The arc is the same feature identified in images of the G ring taken in May 2005. Scientists have seen the arc a handful of times over the past year, and it always appears to be a few times brighter than the rest of the ring and very tightly confined to a narrow strip along the inside edge of the G ring.
Imaging team members believe that this feature is long-lived and may be held together by resonant interactions with the moon Mimas of the type that corral similar ring arcs around Neptune.
The movie consists of 15 frames acquired every half hour over a period of seven-and-a-half hours. The version in the lower panel is vertically stretched by a factor of five to make the arc easier to see.
The clear-filter images in this movie sequence were acquired by the Cassini spacecraft narrow-angle camera on 25 April 2006, at a distance of 2 million kilometres from Saturn. The image scale on the sky at the distance of Saturn is about 24 kilometres per pixel.