This wide-angle view from Cassini, taken on August 16 (2009), shows an amazing amount of relief across the surface of Saturn’s A ring as well as a long shadow cast by the wake of the shepherd moon Daphnis within the Keeler gap.
4.3-mile-wide Daphnis, almost too small to be seen here, sculpts the edges of the Keeler gap into scalloped waves with its gravity as it travels along, and also sends up high plumes of icy ring material before and behind it. Its bright trailing wake casts a long shadow to the left in this view. The rear plumes can be several miles in height above the surrounding rings.
Sunlight striking the rings directly on edge during the planet’s equinox emphasizes some ridged texture along the inner region of the A ring, like grooves on a vinyl record. It’s only every fourteen years do the rings get this kind of dramatic lighting from the sun – during the planet’s spring and autumn equinoxes.
Edge-sculpting by the shepherd moon Pan within the larger Encke Gap is also visible here on the left part of the image, as are some clumps within the bright F ring near the center.
Raw image: NASA/JPL/SSI