Dione in False Colors

This view highlights tectonic faults and craters on Dione, an icy world that has undoubtedly experienced geologic activity since its formation.

To create the enhanced-color view, ultraviolet, green and infrared images were combined into a single black and white picture that isolates and maps regional color differences. This "color map" was then superposed over a clear-filter image. The origin of the color differences is not yet understood, but may be caused by subtle differences in the surface composition or the sizes of grains making up the icy soil.

This view looks toward the leading hemisphere on Dione (1,126 kilometers, or 700 miles across). North is up and rotated 20 degrees to the right.

See PIA07690 for a similar monochrome view.

All images were acquired with the Cassini spacecraft narrow-angle camera on December 24, 2005 at a distance of approximately 151,000 kilometers (94,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 99 degrees. Image scale is 896 meters (2,940 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Note: For more information, see Cassini Detects Hint of Fresh Air at Dione.

Titan and Dione

Saturn's third-largest moon, Dione, can be seen through the haze of the planet's largest moon, Titan, in this view of the two posing before the planet and its rings from NASA's Cassini spacecraft.

The north polar hood can be seen on Titan appearing as a detached layer at the top of the moon here. See PIA08137 and PIA09739 to learn more about Titan's atmosphere and the north polar hood.

See PIA10560 and PIA07638 to learn more about and see a closer view of the wisps on Dione's trailing hemisphere, which appear as bright streaks here.

This view looks toward the sides of Titan (3,200 miles or 5,150 kilometers across) and Dione (698 miles or 1,123 kilometers across) facing away from Saturn. North is up on the moons. This view looks toward the northern, sunlit side of the rings from just above the ring plane.

Images taken using red, green and blue spectral filters were combined to create this natural color view. The images were obtained with the Cassini spacecraft narrow-angle camera on May 21, 2011, at a distance of approximately 1.4 million miles (2.3 million kilometers) from Titan and 2 million miles (3.2 million kilometers) from Dione. Image scale is 9 miles (14 kilometers) per pixel on Titan and 12 miles (19 kilometers) on Dione.

Photo credit: NASA/JPL-Caltech/Space Science Institute

Rhea, Dione and the Rings

The Cassini spacecraft looks past the cratered south polar area of Saturn's moon Rhea to spy the moon Dione and the planet's rings in the distance.

Dione's "wispy" terrain can be seen on the trailing hemisphere of that moon. See PIA10560 to learn more.

This view looks toward the south polar area of the anti-Saturn side of Rhea (1,528 kilometers, or 949 miles across) and the Saturn-facing side of Dione (1,123 kilometers, or 698 miles across). North on the moons is up.

This view looks toward the northern, sunlit side of the rings from just above the ringplane. The rings, closer to Cassini than Dione is, obscure the view of the south of Dione.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on January 11, 2011. The view was acquired at a distance of approximately 61,000 kilometers (38,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 15 degrees. The view was acquired at a distance of approximately 924,000 kilometers (574,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 15 degrees. Image scale is 358 meters (1,175 feet) per pixel on Rhea and 6 kilometers (4 miles) per pixel on Dione.

Photo credit: NASA/JPL/Space Science Institute

Dione's Erulus Crater

The Cassini spacecraft snapped this shot of cratered Dione as it flew by the Saturnian moon on October 17, 2010.

The large crater at the center of the image is Erulus, which is about 120 kilometers, or 75 miles, across. This view looks toward the southern latitudes of the leading hemisphere of Dione (1,123 kilometers, or 698 miles across).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approximately 41,000 kilometers (25,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 53 degrees. Image scale is 240 meters (787 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Dione and Titan

The surface of Saturn's moon Dione is rendered in crisp detail against a hazy, ghostly Titan.

A portion of the "wispy" terrain of Dione's trailing hemisphere can be seen on the right (see PIA12553). Also visible in this image are hints of atmospheric banding around Titan's north pole. To learn more about the northern bands, see PIA08868 and PIA08928. This view looks toward the Saturn-facing hemisphere of Dione (1,123 kilometers, or 698 miles across) and Titan (5,150 kilometers, or 3,200 miles across).

The image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on April 10, 2010. The view was acquired at a distance of approximately 1.8 million kilometers (1.1 million miles) from Dione and 2.7 million kilometers (1.7 million miles) from Titan. Scale in the original image was 11 kilometers (7 miles) per pixel on Dione and 16 kilometers (10 miles) on Titan. The image has been magnified by a factor of 1.5 and contrast-enhanced to aid visibility.

Photo credit:

Dione Passing by Tethys

Saturn's moon Dione passes by the moon Tethys in this Cassini spacecraft depiction of a "mutual event." Mutual events occur when, from the vantage point of Cassini, one moon appears to pass close to or in front of another moon.

Mutual event observations help scientists refine their understanding of the orbits of Saturn's moons. See PIA11692 to watch a movie of a mutual event. Lit terrain seen here is on Saturn-facing, trailing hemisphere side of both Tethys (1,062 kilometers, or 660 miles across) and Dione (1,123 kilometers, or 698 miles across).

The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on March 26, 2010. The view was obtained at a distance of approximately 2 million kilometers (1.2 million miles) from Dione and 2.4 million kilometers (1.5 million miles) from Tethys. Image scale in the original image was 12 kilometers (7 miles) per pixel on Dione and 14 kilometers (9 miles) per pixel on Tethys. The image was contrast enhanced and magnified by a factor of two to enhance the visibility of surface features.

Photo credit: NASA/JPL/Space Science Institute

Stories and Photos of Interest

The Minister finds himself awash in an embarrassment of riches. Due to a tight schedule, he is only able to do one post per day for his MinSEx blog. Alas, the number of stories and photos that he might be able to blog about is a much greater number. Thus, he's going to provide a weekly list of some (but not all) of the stories and photos he's come across in the past week that he thinks his readers might find of interest. Sorted by topic:

The Sun:
Bright Points on the Quiet Sun (Recommended!)

Earth:
PIA13041: NASA's AIRS Instrument Captures Ash Cloud from Icelandic Volcano
PIA13046: NASA Satellite Images Provide Insights Into Iceland Volcanic Plume
PIA13033: Hale Telescope, Palomar Observatory

Moon:
PIA13039: Rimae Prinz Region - Constellation Region of Interest
PIA13038: Exposed Fractured Bedrock in the Central Peak of the Anaxagoras Crater

Saturn:
PIA12613: Brilliant Blip Beyond Saturn
PIA12579: Dione Polar Maps - February 2010
PIA12578: Dione Polar Maps - February 2010
PIA12577: Map of Dione - February 2010
PIA12612: In the Arc
PIA12576: Lightning Flashing on Saturn
PIA12575: First Lightning Flashes on Saturn
PIA12611: Up and Down Tethys
PIA12610: Lost Among Stars

Space Exploration:
A Large Space Station Over Earth
Damage to Apollo 13

Black Holes:
Diagnosis Murder: Study Shows Supermassive Black Holes May Strip Galaxies of Life

Galaxies:
NGC 4651: The Umbrella Galaxy
Explained: Why Many Surveys of Distant Galaxies Miss 90% of Their Targets

Dione and Titan

Saturn's moon Dione passes in front of the larger moon Titan, as seen from the Cassini spacecraft.

This image is part of a mutual event sequence in which one moon passes close to or in front of another. Such observations help scientists refine their understanding of the orbits of Saturn's moons. See PIA11692 to watch a movie of a mutual event.

Lit terrain seen here is on the anti-Saturn side of Dione (1,123 kilometers, or 698 miles across) and the leading hemisphere of Titan (5,150 kilometers, or 3,200 miles across).

The image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on March 12, 2010. The view was obtained at a distance of approximately 2.2 million kilometers (1.4 million miles) from Dione and 3.6 million kilometers (2.2 million miles) from Titan. Scale in the original image was 13 kilometers (8 miles) per pixel on Dione and on 21 kilometers (13 miles) per pixel Titan. The image has been magnified by a factor of 1.5 and contrast-enhanced to aid visibility.

Photo credit: NASA/JPL/Space Science Institute

Dione's Wispy Terrain

Wispy terrain winds across the trailing hemisphere of Saturn's moon Dione in this Cassini view taken during the spacecraft's Jan. 27, 2010 non-targeted flyby.

Cassini came within about 45,000 kilometers (28,000 miles) of the moon during this flyby, but this image was acquired at a distance of approximately 137,000 kilometers (85,000 miles) from Dione. See PIA06163 for an older, closer view of Dione's wispy fractures. This view looks toward the anti-Saturn side and trailing hemisphere of Dione (1,123 kilometers, or 698 miles across). North on Dione is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 27, 2010. The view was obtained at a Sun-Dione-spacecraft, or phase, angle of 38 degrees. Image scale is 819 meters (2,687 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute