Cassini’s Christmas Gift: a Peek at Prometheus

Captured on Christmas Day, this is a raw image from Cassini showing Saturn’s F ring buckling inwards at two places due to the gravitational tug of its inner shepherd moon, Prometheus, seen at center. As the irregularly-shaped moon approaches the ring material in its looping orbit around Saturn it draws material from the ring in…

You say potato, I say Prometheus.

Here’s a nicely processed-and-polished photo of Saturn’s moon Prometheus, fresh from the Cassini imaging center at the Space Science Institute in Boulder, CO. Taken during the spacecraft’s flyby of the F-ring’s shepherd moon earlier this year, this image shows Prometheus’ potato-like shape and heavily cratered surface on its trailing side, dimly illuminated by reflected light…

Prometheus Passing

Prometheus, shepherd moon of Saturn’s F ring, is featured in this dramatic image from Cassini taken as it passed by at a distance of 23,000 miles (37,014 km) on January 27, 2010. This is the closest Cassini has come to Prometheus. The image above has been extensively cleaned up in regard to CCD pixel noise…

A Visit to Prometheus

This raw image, taken by the Cassini spacecraft on December 26, 2009 (on a certain space blogger’s birthday, by the way) shows an amazing view of Prometheus, one of Saturn’s many shepherd moons. This is the closest yet that Cassini has come to the 96-mile-long oblong moon. Details of its cratered surface are visible, as…

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…

Watch Saturn’s Moons Race Inside the Rings

Round and round they go… the animation above, made from 14 raw images taken by NASA’s Cassini spacecraft on August 23, 2016, shows the moons Prometheus and Atlas orbiting Saturn within the Roche Division gap between its A (top right) and F (center) rings. The gravitational tug of Prometheus (92 miles / 148 km long) is strong…

A Visual Demonstration of Gravity, Courtesy of Cassini

Prometheus is at it again! On Feb. 5, Cassini acquired a series of images with its narrow-angle camera of Saturn’s reflective and ropy F ring, around the inside of which travels the shepherd moon Prometheus. As it orbits Saturn it regularly arcs outwards toward the inner edge of the F ring and tumbles back inwards…

That’s No Space Station, It’s a MOON!

First Alderaan, then Prometheus?? Here we go again! Saturn’s moon Mimas looks uncannily like the Death Star, and this animation by Diamond Sky Productions makes the resemblance even more apparent. Now witness the power of this fully-armed battle station! (No shepherd moons were harmed in the making of this video.) Video © Diamond Sky Productions,…

Ghosts of Worlds Passed

Saturn’s F ring is a fascinating structure. Made of fine icy particles — most no larger than the particulates found in cigarette smoke — it orbits Saturn just outside the A ring and is easily perturbed by the gravity of nearby moons and embedded moonlets, which create streamers and clumps that rise up in fanciful…

Daphnis Is Back!

It’s been a while since I posted an image of my favorite moon of Saturn, but while looking through some recent raw images returned by the Cassini spacecraft I spotted it: Daphnis, the little sculptor shepherd moon!

A Fistful of Moons

This image from Cassini shows no less than five of Saturn’s moons in the same frame: Rhea (1,528 kilometers, or 949 miles across) is largest in the foreground; Dione (1,123 kilometers, or 698 miles across) can be seen just above the rings below Rhea near the center; Prometheus (86 kilometers, or 53 miles across) is just barely…