Tethys and Titan

Terrain on Saturn's moon Tethys, defined with craters, is shown in front of the hazy atmosphere of the larger moon Titan in this Cassini spacecraft image.

Titan is 5,150 kilometers, or 3,200 miles, across. Tethys is 1,062 kilometers, or 660 miles, across. This view looks toward the Saturn-facing sides of Titan and Tethys.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on October 17, 2009. The view was obtained at a distance of approximately 1.9 million kilometers (1.2 million miles) from Tethys and 2.9 million kilometers (1.8 million miles) from Titan. Image scale is 12 kilometers (7 miles) per pixel on Tethys and 17 kilometers (11 miles) per pixel on Titan.

Photo credit: NASA/JPL/Space Science Institute

Narrow Band

The shadows of Saturn's rings cast onto the planet appear as a thin band at the equator in this image taken as the planet approached its August 2009 equinox.

The novel illumination geometry that accompanies equinox lowers the Sun's angle to the ringplane, significantly darkens the rings, and causes out-of-plane structures to look anomalously bright and to cast shadows across the rings. These scenes are possible only during the few months before and after Saturn's equinox which occurs only once in about 15 Earth years. Before and after equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons (see PIA11657), but also the shadows of newly revealed vertical structures in the rings themselves (see PIA11665). For an earlier view of the rings' wide shadows draped high on the northern hemisphere, see PIA09793.

The planet's southern hemisphere can be seen through the transparent D ring in the lower right of the image. The rings have been brightened by a factor of 9.5 relative to the planet to enhance visibility.

This view looks toward the northern, unilluminated side of the rings from about 30 degrees above the ringplane.

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 wide-angle camera on July 18, 2009 at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn. Image scale is 122 kilometers (76 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

A-Ring Propeller

A propeller-shaped structure, created by an unseen moon, can be seen in Saturn's A ring.

The propeller, which looks like a small, dark line interrupting the bright surrounding ring material, is in the upper left of this image near the edge of the Keeler Gap. See PIA12790 to learn more about propellers.

This view looks toward the southern, unilluminated side of the rings from about 16 degrees below the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 3, 2010. The view was acquired at a distance of approximately 279,000 kilometers (173,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 16 degrees. Image scale is 1 kilometer (3,300 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Enceladus and Saturn's Rings

Saturn's moon Enceladus, seen beyond the outline of the planet's night side, spews water ice from its south polar region.

Enceladus is farther from Cassini than the planet is here. The plumes can be faintly seen at the bottom of the moon in this image. See PIA11688 to learn more about Enceladus (504 kilometers, or 313 miles across).

This unusual view of the planet and rings is possible because some sunlight scatters through the uppermost part of Saturn's atmosphere to reach Cassini's cameras on the night side of the planet. See PIA12603 for an explanation of this viewing geometry.

This view looks toward the southern, unilluminated side of the rings from about 5 degrees below the ringplane.

Enceladus and its plumes have been brightened by a factor of two relative to the planet and rings.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on December 25, 2009. The view was acquired at a distance of approximately 617,000 kilometers (384,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 174 degrees. Image scale is 37 kilometers (23 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Telesto

The smooth surface of Saturn's moon Telesto is documented in this image captured during the Cassini spacecraft's August 27, 2009, flyby.

See PIA07696 to learn more about Telesto's lack of craters.

This view looks toward the leading hemisphere of Telesto (25 kilometers, or 16 miles across). North on the moon is up and rotated 3 degrees to the right.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was obtained at a distance of approximately 36,000 kilometers (22,000 miles) from Telesto and at a Sun-Telesto-spacecraft, or phase, angle of 48 degrees. Image scale is 214 meters (702 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Promethean Shadow Before Equinox

Saturn's moon Prometheus casts a long shadow across the A ring in the middle-right side of this Cassini spacecraft image taken shortly before the planet's August 2009 equinox.

Prometheus (86 kilometers, or 53 miles across) orbits in the Roche Division between the thin F ring and the A ring. The novel illumination geometry created around the time of Saturn's August 2009 equinox allows out-of-plane structures and moons orbiting in or near the plane of Saturn's equatorial rings to cast shadows onto the rings. These scenes are possible only during the few months before and after Saturn's equinox, which occurs only once in about 15 Earth years. To learn more about this special time and to see movies of moons' shadows moving across the rings, see PIA11651 and PIA11660.

This view looks toward the northern, unilluminated side of the rings from about 31 degrees above the ringplane. Many stars are visible. The rings and stars have been brightened by a factor six relative to Prometheus to enhance visibility.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 29, 2009. The view was acquired at a distance of approximately 1.4 million kilometers (870,000 miles) from Prometheus and at a Sun-Prometheus-spacecraft, or phase, angle of 93 degrees. Image scale is 9 kilometers (6 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Note: The photo also shows several streamer channels and gravitational perturbations in the F-Ring. For more on this topic, see Fleeing the Scene and Fan Structures in Saturn's F-Ring.

Rhea

The Cassini spacecraft looks to the cratered surface of Saturn's second largest moon, Rhea.

Rhea is 1,528 kilometers, or 949 miles, across. This view looks toward the anti-Saturn side of Rhea. North on Rhea is up and rotated 30 degrees to the right.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 3, 2010. The view was obtained at a distance of approximately 93,000 kilometers (58,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 62 degrees. Image scale is 6 kilometers (4 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Saturn and Mimas

The immense size of Saturn is emphasized in this Cassini spacecraft portrait that features the moon Mimas shown in front of the planet.

Mimas (396 kilometers, or 246 miles across) appears as only a small dot above the rings near the center of the image. This view looks toward the northern, sunlit side of the rings from about one degree above the ringplane.

The image was taken with the Cassini spacecraft wide-angle camera on October 17, 2009 using a spectral filter sensitive to wavelengths of near-infrared light centered at 752 nanometers. The view was obtained at a distance of approximately 1.7 million kilometers (1.1 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 87 degrees. Image scale is 99 kilometers (62 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Epimetheus

The Cassini spacecraft snapped this high-resolution image of Saturn's small moon Epimetheus during the spacecraft's non-targeted flyby on April 7, 2010.

The view was obtained at a distance of approximately 107,000 kilometers (66,500 miles) from Epimetheus and at a Sun-Epimetheus-spacecraft, or phase, angle of 62 degrees. See PIA09813 and PIA06226 for even closer views.

Lit terrain seen here is mostly on the Saturn-facing side of Epimetheus (113 kilometers, or 70 miles across). North on Epimetheus is up and rotated 26 degrees to the left. The image was taken in visible light with the Cassini spacecraft narrow-angle camera. Image scale is 641 meters (2,103 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

B-Ring Spokes, Pandora and Dione

Bright spokes grace Saturn's B ring in this Cassini spacecraft snapshot that also features a couple of the planet's moons large and small.

Dione (1,123 kilometers, or 698 miles across) can be seen in the upper left of the image. Pandora (81 kilometers, or 50 miles across) appears as a small speck beyond the thin F ring near the center left of the image. The spokes are particularly noticeable on the far right of the image. See PIA12605 to learn more about spokes.

This view looks toward the northern, sunlit side of the rings from about 8 degrees above the ringplane. Pandora has been brightened by a factor of two relative to the rings and Dione to enhance visibility. Dione is overexposed here.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on May 30, 2010. The view was acquired at a distance of approximately 1.9 million kilometers (1.2 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 104 degrees. Image scale is 111 kilometers (69 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Mountains near Adiri on Titan

This mosaic, made from radar images obtained by NASA's Cassini spacecraft, shows parallel mountain chains on Saturn's moon Titan, near an equatorial region known as Adiri. This mosaic focuses on an area around 10 degrees south latitude and 145 degrees east longitude. The annotated version [above] shows topographic profiles obtained by the radar instrument, with red areas showing the highest elevation (in this image, 250 meters above the mean radius of Titan) and purple showing the lowest (in this image, 450 meters below the mean radius of Titan). That version also shows a grid for latitude and longitude.

Scientists believe the structures rose up because the lithosphere, the outermost layer of the surface, folded up during deformation of the outer water ice shell.

Cassini's radar instrument obtained the black-and-white image of the terrain on February 22, and October 28, 2005. In radar images, objects appear bright when they are tilted toward the spacecraft or have rough surfaces. The topographical data were derived from the same flybys.

For another view of this terrain, see PIA03566.

Photo credit: NASA/JPL-Caltech

Note: For some other radar images of Titan's surface, see PIA13330: Mountains North of Aaru on Titan and PIA13331: Mountains on the Northwest Border of Xanadu, Titan.

Closest View of Daphnis

The Cassini spacecraft captures here one of its closest views of Saturn's ring-embedded moon Daphnis.

This image was taken July 5, 2010, at a distance of only about 75,000 kilometers (47,000 miles) from Daphnis. Seen at the upper left of this image, Daphnis (8 kilometers, or 5 miles across) appears in the Keeler Gap near the edge waves it has created in the A ring. The moon's orbit is inclined relative to the plane of Saturn's rings. Daphnis' gravitational pull perturbs the orbits of the particles of the A ring that form the Keeler Gap's edge, and sculpts the edge into waves having both horizontal (radial) and out-of-plane components. Material on the inner edge of the gap orbits faster than the moon so that the waves there lead the moon in its orbit. Material on the outer edge moves slower than the moon, so waves there trail the moon. See PIA11656 to learn more about this process.

Daphnis can also be seen casting a short shadow on the A ring.

This view looks toward the northern, sunlit side of the rings from about 14 degrees above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera at a Sun-Daphnis-spacecraft, or phase, angle of 58 degrees. Image scale is 452 meters (1,483 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Rhea, Rings & Shadows

Saturn's moon Rhea is gently lit in front of a background of the planet with a wide shadow cast by the rings which are seen nearly edge-on.

This view looks toward the anti-Saturn side of Rhea (1,528 kilometers, or 949 miles across) and toward the northern, sunlit side of the rings from just above the ringplane.

The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on May 8, 2010. The view was obtained at a distance of approximately 2.1 million kilometers (1.3 million miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 101 degrees. Image scale is 13 kilometers (8 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Thirteen New Names for Features on Rhea

From the USGS Astrogeology Science Center:

Thirteen new names have been approved for features on Rhea, including 1 crater, 5 catenae, 5 chasmata, and 2 fossae. The descriptor terms and spellings of 2 approved names have also been changed; Kun Lun Chasma was changed to Kunlun Linea, and Pu Chou Chasma was changed to Puchou Catenae. For more information, see the list of Rhea feature names and the map of Rhea in the Gazetteer of Planetary Nomenclature.

Atmospheric Aspects of Titan

The Cassini spacecraft examines the characteristics of Titan's atmosphere as it peers at Saturn's largest moon using a filter sensitive to visible violet light.

This image shows atmospheric banding around Titan's north pole and reveals hints of the moon's seasonal hemispheric dichotomy near the equator. To learn more about the northern bands, see PIA08868 and PIA08928. See PIA11603 to learn more about the seasonal dichotomy between the northern and southern hemispheres.

This view looks toward the anti-Saturn side of Titan (5,150 kilometers, or 3,200 miles across). North on Titan is up and rotated 23 degrees to the left.

The image was taken in visible violet light with the Cassini spacecraft wide-angle camera on June 21, 2010. The view was obtained at a distance of approximately 170,000 kilometers (106,000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 33 degrees. Image scale is 10 kilometers (6 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Enceladus and the E-Ring

As Enceladus spews water ice from its south polar region, the Cassini spacecraft chronicles the moon creating Saturn's faint E ring, in which the moon orbits.

See PIA11688 and PIA08321 to learn more about this active moon and how it creates the E ring. The E ring can just barely be seen here. The most brightly lit terrain seen on the moon here (on the left of the moon) is illuminated by the Sun and is on the leading hemisphere of Enceladus (504 kilometers, or 313 miles across). Light reflected off Saturn covers a larger area on the Saturn-facing side of the moon on the right.

North on Enceladus is up. This view looks toward the northern, sunlit side of the rings from just above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 26, 2010. The view was obtained at a distance of approximately 993,000 kilometers (617,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 162 degrees. Image scale is 6 kilometers (4 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Pan in the Encke Gap

Saturn's small, ring-embedded moon Pan, on the extreme right of this Cassini spacecraft image, can be seen interacting with the ringlets that share the Encke Gap of the A ring with this moon.

Pan is 28 kilometers, or 17 miles, across. This view looks toward the northern, sunlit side of the rings from about 11 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 2, 2010. The view was acquired at a distance of approximately 875,000 kilometers (544,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 130 degrees. Image scale is 5 kilometers (3 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Pandora

The Cassini spacecraft captured this close view of Saturn's moon Pandora during the spacecraft's flyby on June 3, 2010.

Pandora is 81 kilometers (50 miles) across, and orbits beyond Saturn's thin F ring, which is shepherded by Pandora and Prometheus. See PIA07632 for an earlier, closer view of Pandora.

This view looks toward the Saturn-facing side of Pandora. North on Pandora is up and rotated 20 degrees to the left.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was obtained at a distance of approximately 101,000 kilometers (63,000 miles) from Pandora and at a Sun-Pandora-spacecraft, or phase, angle of 28 degrees. Image scale is 603 meters (1,980 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Saturn, Tethys and Rhea

Looking up toward Saturn's southern hemisphere, the Cassini spacecraft pictures a pair of the planet's moons orbiting in the distance.

Tethys and Rhea orbit in the plane of the planet's rings, but from this vantage point they appear to be below the planet. Tethys (1,062 kilometers, or 660 miles across) is near the center of the image, and Rhea (1,528 kilometers, or 949 miles across) is in the lower right.

This view looks toward the southern, unilluminated side of the rings from about 12 degrees below the ringplane.

The image was taken with the Cassini spacecraft wide-angle camera on June 29, 2010 using a spectral filter sensitive to wavelengths of near-infrared light centered at 728 nanometers. The view was obtained at a distance of approximately 2.1 million kilometers (1.3 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 100 degrees. Image scale is 124 kilometers (77 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Fan Structures in Saturn's F-Ring

Bright clumps of ring material and a fan-like structure appear near the core of Saturn's tenuous F ring in this mosaic of images from NASA's Cassini spacecraft. Such features suggest the existence of additional objects in the F ring.

These discontinuous clumps near the core of the F ring may be created by the passage of the ring's shepherding moon Prometheus, and they can be seen casting narrow shadows that extend toward the bottom of the mosaic. The shadows are marked with arrows in the annotated version. On the right of the mosaic, a "fan" can be seen dissipating above the bright ring core. The fan (marked "F" in the annotated version) is a series of channels within the F ring's particles that appear to have a common origin but that spread outward radially in different directions. Gravitational perturbations on the ring material by a moonlet or clump of material can create these fans. The moonlet or clump orbits more or less elliptically compared to the rest of the F ring can create these fans. It is probably embedded in the ring and is causing the base of the fan channels to meet. See PIA1285 and PIA12786 for similar observations of such fans.

The diagonal streamer-channels are periodically created by the gravity of the potato-shaped moon Prometheus which is 148 kilometers (92 miles) on its longest side but is on average 86 kilometers (53 miles) across. To learn more and to watch a movie of this streamer-channel phenomenon, see PIA08397.

The images have been re-projected in this mosaic so that the F ring appears straightened rather than curved and compressed azimuthally (along the ring). This change represents a scale compression in the horizontal direction of about 33 to one which is why Prometheus looks like a bright line. Prometheus is marked "Pr" in the annotated version.

This sequence of 42 images was taken over a span of one hour, seven minutes. The earliest image is on the right, and time progresses moving left in the mosaic. Each image was cropped, re-projected and placed side by side in this montage. Scale in the original images was about 3 kilometers (2 miles) per pixel. The images were contrast enhanced and re-projected to a scale of 33 kilometers (21 miles) per pixel in the mosaic's horizontal direction and one kilometer (0.6 miles) per pixel in the mosaic's vertical direction. The single, cropped inset of the clumps included here was then magnified by a factor of two.

The view in the original images looked toward the northern, unilluminated side of the rings from about 70 degrees above the ring plane.

The images were taken in visible light with the Cassini spacecraft narrow-angle camera on December 8, 2008. The view was obtained at a range of distances from approximately 597,000 kilometers (371,000 miles) to 615,000 kilometers (382,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 77 degrees.

Photo credit: NASA/JPL/Space Science Institute

Notes: For other pictures and information in this series, see the following: PIA12784: Multiple F-Ring "Fans", PIA12786: "Fan" in the F Ring, and PIA12787: The Effect of Prometheus on the F Ring, the last of which includes a very interesting (but high memory-consuming) animation.