The heavens often seem vast and unchanging as seen from Earth, but movement in the skies is the norm. The relative motions of both Cassini and Enceladus over a 15-minute period create the movement seen in this movie sequence.
Cassini has monitored Enceladus (313 miles or 504 kilometers across) with a particular interest in the plumes and the geology of the south polar region for many years. Different viewing geometries give scientists different information, and the resulting animation gives us a unique "spacecraft's eye" view of the flyby.
The movie is a composite of six images taken with the Cassini spacecraft narrow-angle camera on August 1, 2017 using filters that allow infrared, green, and ultraviolet light. The image filter centered on 930 nm (IR) was is red in this image, the image filter centered on the green is green, and the image filter centered on 338 nm (UV) is blue.
The view was obtained at a distance of approximately 112,000 miles (181,000 kilometers) from Enceladus. Image scale is about 0.6 mile (1 kilometer) per pixel.
Image Credit: NASA/JPL-Caltech/Space Science Institute
Explanation from: https://photojournal.jpl.nasa.gov/catalog/PIA21344
Arsalan
Monday, September 4, 2017