A Fresh Perspective

Prometheus’ shadow slices through the strands of Saturn’s F ring in this low-angle view from the Cassini orbiter. The sunlit shepherd moon is a bit overexposed in this image, in order to capture the bands of the rings. This view is looking outwards across the edge of the B ring (at lower left), the darker…

Around the Track

Shepherd moons Prometheus and Daphnis race around Saturn’s rings within their respective gaps, affecting the ring material in their own distinct ways. Prometheus, on the left side, pulls the bright, ropy F ring into streamers while tiny Daphnis, embedded in the 25-mile-wide Keeler gap at lower center, sends up a mound of darker A ring…

Shepherds Passing

  Without as much as a wave shepherd moons Prometheus and Atlas pass by each other, each on their own paths around the rings. Prometheus, casting a long shadow,  pulls at the F ring’s bands of material while smaller Atlas guards the edges of the A ring. The larger is 93 miles across at its…

Shepherds Fly

  Two of Saturn’s smaller moons pass by Cassini’s wide-angle camera in this animation sequence, made from 60 raw images taken on May 26, 2009. Prometheus enters first, stage right, deforming the ringlets of the F ring with its gravity, and is followed shortly after by Atlas, taking the inside track around the edge of…

Streaming Along

  Another animation, this time from April 24, 2009, made from 116 raw images from the Cassini spacecraft. The orbiting Cassini focused its camera on Prometheus as it dipped into the F ring and back out again, pulling the icy dust into wispy strands with its passing. Prometheus’ oblong shape can be seen clearly here…it…

The Pull of Prometheus

Prometheus’ effect on Saturn’s ropy F ring is evident in this photo from Cassini, taken March 7, 2009. As the irregularly-shaped shepherd moon approaches the ring material in its looping orbit around Saturn, it draws material from the ring in towards itself, warping and stretching the ring particles into waving streamers that eventually settle and…

Prometheus Unbound

  One of several tiny “shepherd” moons, a well-lit Prometheus cruises the gap between Saturn’s A and F rings, clearing the channel while pulling up a small plume of material from the ropy F ring as it passes by. This is from raw image data shot by Cassini on February 10, 2009. I adjusted the image…