A Fan of Shadows

Cassini captured this visible-light image on October 16, 2010, showing a thick clump of icy material in Saturn’s bright F ring casting a “fan” of thin shadows. Clumps like this have been seen many times before and may be caused by the gravitational effects of passing shepherd moons like Prometheus or as-of-yet undiscovered moonlets within the ropy…

A Shepherd’s Shadow

Inner shepherd of Saturn’s ropy F-ring, Prometheus casts a long shadow through the ring’s icy haze in this beautifully reworked Cassini image by Gordan Ugarkovic. Discovered by Voyager in 1980 Prometheus completes a tumbling orbit around Saturn every 14.7 hours, regularly dipping into the F-ring in a scalloped path and pulling out streamers of icy…

Moon Quartet

Four of Saturn’s 62 moons are seen passing each other in this animation, composed from 22 raw images taken by the Cassini spacecraft on July 27, 2010. Epimetheus, Prometheus, Janus and tiny Atlas all orbit Saturn within or near the ring system. As the animation begins, the potato-shaped Prometheus is just “rounding the bend” inside…

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…

Meet the Clumps

87,000 miles from the cloudtops of Saturn’s equator writhes the hazy cords of the F ring, a braided belt of icy dust that shifts and twists around and over itself. Clumps of material gather together and separate, and make the thin ring vary in thickness anywhere from under 20 miles to over 300 miles wide….

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…

Regarding a Ring

  Made from 127 raw images received from the Cassini spacecraft on April 17th, this sequence shows the varied structure of the F ring as it is influenced by passing moons, clumps of material and its own twisted composition. Initially calm, with only background stars marking the passage of time, a passing moon outside the…

Dawn’s Light

The light of daybreak illuminates Saturn’s northern hemisphere and ring system in this dramatic image taken on March 20 by the Cassini spacecraft. From Saturn outward (lower right to upper left) the C, B, A, and thin F rings are visible. The B and A rings are separated by a darker band of thing rings…

Streaming Content

  This 14-frame animation shows the effect of Prometheus on Saturn’s F ring as it travels alongside, its gravity pulling the ring material into streamers that trail in its wake. A clump of ring material leads in front of the moon on the opposite side of the ring. Honestly, I’m not sure what causes this…