Surge in the Ring

An ethereal, glowing spot appears on Saturn's B ring in this view from NASA's Cassini spacecraft. There is nothing particular about that place in the rings that produces the glowing effect -- instead, it is an example of an "opposition surge" making that area on the rings appear extra bright.

An opposition surge occurs when the Sun is directly behind the observer looking toward the rings. The particular geometry of this observation makes the point in the rings appear much, much brighter than would otherwise be expected.

This view looks toward the sunlit side of the rings from about 28 degrees above the ring plane. The image was taken in visible light with the Cassini wide-angle camera on June 26, 2016.

The view was acquired at a distance of approximately 940,000 miles (1.5 million kilometers) from the rings and at a Sun-ring-spacecraft, or phase, angle of 0 degrees. Image scale on the rings at center is 56 miles (90 kilometers) per pixel.

http://photojournal.jpl.nasa.gov/catalog/PIA20496