A vertically extended structure or object in Saturn's F ring casts a shadow long enough to reach the A ring in this Cassini image taken just days before planet's August 2009 equinox.
The structure can be seen as a bulge within the bright core of the F ring on the left of the image. The structure rises far enough above the ring plane for the shadow to be cast across the Roche Division and onto the A ring. The shadow is barely visible stretching across the top right quadrant of the image. The shadow appears very faint here because this view looks toward the unlit side of the rings.
NASA/JPL/Space Science Institute