A nice view of the tiny Saturn moon Prometheus and the wave in the F ring created by it’s gravitational wake that its gravity creates.
Have a look at our page about Prometheus.
The original caption:
The thin sliver of Saturn’s moon Prometheus lurks near ghostly structures in Saturn’s narrow F ring in this view from NASA’s Cassini spacecraft. Many of the narrow ring’s faint and wispy features result from its gravitational interactions with Prometheus (86 kilometers, or 53 miles across).
Most of the small moon’s surface is in darkness due to the viewing geometry here. Cassini was positioned behind Saturn and Prometheus with respect to the sun, looking toward the moon’s dark side and just a bit of the moon’s sunlit northern hemisphere.
Also visible here is a distinct difference in brightness between the outermost section of Saturn’s A ring (left of center) and rest of the ring, interior to the Keeler Gap (lower left).
This view looks toward the sunlit side of the rings from about 13 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 13, 2017.
The view was acquired at a distance of approximately 680,000 miles (1.1 million kilometers) from Saturn. Image scale is 4 miles (6 kilometers) per pixel.
Credit: NASA/JPL-Caltech/Space Science Institute