"Penumbral fade" on Saturn's Rings

Caption NASA:"As the particles comprising Saturn's A-Ring slip into the Planet's shadow, they find themselves briefly in the penumbra of Saturn's shadow. In this very narrow region along the edge of the shadow, part (but not all) of the Sun is still visible around the side of the Planet, creating only a partial shadow there and making the shadow edge look fuzzy.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 26, 2006 at a distance of approx. 1,5 MKM (such as about 900.000 miles) from Saturn. Image scale is roughly 9 Km (about 5 miles) per pixel".