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Our Best Ever Look at Pan, Saturn’s Little “UFO”

Images of the shepherd moon Pan captured by Cassini on March 7, 2017. (Credit: NASA/JPL-Caltech/SSI. Animation by Jason Major.)

Behold the almighty Pan! Thanks to Cassini’s ring-grazing orbits we’ve just received the highest-resolution images ever of Pan—which, at only about 17 miles (27 km) across admittedly isn’t very “almighty” but its flying saucer-like shape is really quite fascinating!

The raw images above were acquired by Cassini on March 7, 2017 and received on Earth on March 8. I assembled them into an animation to show some of the 3D shape of the little shepherd moon, which orbits Saturn inside the 200 mile wide Encke Gap in the A ring.

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Ring Racer (Take Two)

I came across this image today while going through the latest Cassini PDS (Planetary Data System) release, and remembered how excited I was to see it the first time when it came in last June. If you missed it, here it is again (with an image fresh off the PDS!)

Daphnis churns up the edges of the Keeler Gap

Man, I just LOVE this stuff. 🙂

This has to be one of the coolest images yet of one of my favorite subjects: Saturn’s moon Daphnis casting a shadow and riling up the rings as it travels along the 26-mile-wide Keeler Gap, a channel it keeps clear around the outer edge of the A ring. The image above is a cropped and rotated version of a raw image sent back from the Cassini spacecraft today.

The four-and-a-half mile wide Daphnis was first seen by Cassini in 2005. Read the rest of this entry

Ring Racer

Daphnis churns up the edges of the Keeler Gap

Man, I just LOVE this stuff. 🙂

This has to be one of the coolest images yet of one of my favorite subjects: Saturn’s moon Daphnis casting a shadow and riling up the rings as it travels along the 26-mile-wide Keeler Gap, a channel it keeps clear around the outer edge of the A ring. The image above is a cropped and rotated version of a raw image sent back from the Cassini spacecraft today.

Daphnis and Pan making waves

The four-and-a-half mile wide Daphnis was first seen by Cassini in 2005. As it travels, its gravity “sculpts” the fine, icy particles along the edge of the gap into scallops, not only horizontally but also vertically, sending waves of ring bits as high as a mile or so above and below the ringplane. This phenomenon became clear as Saturn approached its spring equinox last August, when light from the sun hit the planet parallel to the equator and made small details like this visible because of the shadows they cast. Even now, almost a year later, the angle of the sunlight is still low enough to keep the shadows long…Saturn’s year is 29 Earth years long so it takes much longer than a few months to get from spring to summer.

The original raw image had another treat as well: the larger shepherd moon Pan was also casting its shadow and causing some gravitational streamers of its own along its path in the Encke Gap! Two dynamic moons in one image…ladies and gentlemen this is Cassini at its best!

Image: NASA/JPL/Space Science Institute

Flying Pan

The shepherd moon Pan casts its shadow

Making a complete orbit in just under 14 hours, the 17-mile-wide shepherd moon Pan cruises around Saturn within the Encke gap in the A ring. In the image above, taken by Cassini on January 8, we can see Pan casting a sliver of a shadow onto the outer edge of the gap as it causes faint trailing disturbances behind it along the gap’s inner edge.

Pan shares the 202-mile-wide Encke gap with several thin ringlets too. Its passing seems to have riled up one of the ringlets here, causing it to pick up extra-bright highlighting from the sun.

This image was taken with Cassini’s narrow-angle camera from a position below the ringplane. Some stars are also visible, outside as well as through the rings. Saturn’s own huge shadow darkens the top portion of the image.

Image: NASA/JPL/Space Science Institute

Shadow Caster

Pan casts its shadow onto Saturn's rings

It’s been a while since I posted any moon shadow images but they’re always cool to look at, since they add another dimension to a scene that can sometimes be hard to put into context. This image, taken by Cassini on January 10 and released today, shows the 12-mile-wide shepherd moon Pan cruising along within the Encke Gap, a 200-mile-wide space in Saturn’s bright A ring. Pan’s shadow falls upon the particles along the outer edge of the gap.

The little moon clips along at a good pace, too, completing an orbit of the giant planet every 13.8 hours!

As time passes and Saturn gets further from its spring equinox, which occurred back on August 11, the shadows of the moons nearest the rings will get shorter and eventually no longer strike the rings themselves. This visual phenomenon was a real treat for all Cassini enthusiasts but once the shadows dip below the ringplane we won’t be seeing much more of them for a while…the Cassini mission may have been extended for another seven years but that’s still not enough time for the spacecraft to witness another equinox, since it takes Saturn over 29 years to complete a full trip around the Sun!

For more info on Saturn’s ring system and the Cassini mission click here.

Image: NASA/JPL/Space Science Institute

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Capturing Pan’s Shadow

 

Pan Cruises the Encke Gap

Pan Cruises the Encke Gap

Cassini took this photo yesterday, May 9th, as 16-mile-wide shepherd moon Pan passed along its path through the Encke Gap. Its shadow falls upon the A ring, pointing toward Saturn.

(I colored the image to approximate visible light coloration based on other true-color calibrations. The original raw image can be seen here.)

Pan is lemon-shaped, its long axis permanently pointed toward Saturn. It makes a complete orbit around the giant planet in about 14 hours, traveling the 202-mile-wide Encke Gap in the A ring. Three other corded ringlets, two seen clearly above, also inhabit the gap, discovered in 1888 by James Edward Keeler and named after German astronomer Johann Encke.

Stars are visible through the rings, illustrating their transparency.

Image credit: NASA/JPL/Space Science Institute/J. Major

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