[math-fun] As long as we're talking astronomy

http://media.zenfs.com/en_us/News/Reuters/2012-12-19T035245Z_616564795_TM3E8... shows the ridiculously complicated illumination of Saturn's nightside by sunlight scattered off the rings, some of which is then viewed though the rings. At 4 o'clock on the limb, there is even an arc filtered through the dayside rings and then the upper atmosphere. But I don't understand: 1) Why the crisp silhouettes of the near rings against the (false color) green background seem discontinuous with the arcs outside the planet's shadow, presumably viewed by scattered, transmitted sunlight. 2) The bluish white haze extending far to the right from 5 o'clock on the limb. --rwg