Dione

Like the Voyager spacecraft that came before, the Cassini spacecraft chronicles "wispy" terrain on Saturn's moon Dione.

See PIA10560 to view another image of these bright fractures on the moon's trailing hemisphere. This view looks toward the area between the Saturn-facing side and trailing hemisphere of Dione (1,123 kilometers, or 698 miles across). North is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on December 26, 2009. The view was acquired at a distance of approximately 1 million kilometers (621,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 42 degrees. Image scale is 6 kilometers (4 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Saturn, in Infrared

This false-color composite image, constructed from data obtained by NASA's Cassini spacecraft, shows Saturn's rings and southern hemisphere. The composite image was made from 65 individual observations by Cassini's visual and infrared mapping spectrometer in the near-infrared portion of the light spectrum on November 1, 2008. The observations were each six minutes long.

In this image constructed from data collected in the near-infrared wavelengths of light, scientists designated blue to indicate sunlight reflected at a wavelength of 2 microns, green to indicate sunlight reflected at 3 microns and red to indicate thermal emission at 5 microns. Saturn's rings reflect sunlight at 2 microns, but not at 3 and 5 microns, so they appear deep blue. Saturn's high altitude haze reflects sunlight at both 2 and 3 microns, but not at 5 microns, and so it appears green to blue-green. The heat emission from the interior of Saturn is only seen at 5 microns wavelength in the spectrometer data, and thus appears red. The dark spots and banded features in the image are clouds and small storms that outline the deeper weather systems and circulation patterns of the planet. They are illuminated from underneath by Saturn's thermal emission, and thus appear in silhouette.

Photo credit: NASA/JPL/University of Arizona/University of Leicester

Note: For similar images and a movie that highlight Saturn's Auroras Australis, see PIA13402: Glowing Southern Lights,
PIA13403: Four Aurora Snapshots and PIA13404: Dancing Southern Lights of Saturn. A small Quicktime movie of the auroras can be watched here.

Conjoined Moons

Looking like half of a figure eight, two of Saturn's moons appear conjoined in this Cassini spacecraft image.

The moon Dione, at the top in the image, is actually closer to the spacecraft here. However, because of the similar albedo, or reflectivity, of the two moons and because of the location of a particularly large crater near the south polar region of Dione, the moon appears to blend seamlessly with Rhea. The large, faint crater Evander is centered at about 57 degrees south latitude, 145 degrees west longitude and can also be seen in the Dione south polar map (see PIA12579).

Lit terrain seen here is on the anti-Saturn side of Dione (1,123 kilometers, or 698 miles across) and on the area between the anti-Saturn and leading hemisphere on Rhea (1,528 kilometers, or 949 miles across).

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 27, 2010. The view was acquired at a distance of approximately 1.1 million kilometers (684,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 78 degrees. The view was acquired at a distance of approximately 1.6 million kilometers (994,000 miles) from Rhea and at a Sun-Rhea-spacecraft, or phase, angle of 78 degrees. Image scale is 7 kilometers (4 miles) per pixel on Dione and 10 kilometers (6 miles) on Rhea.

Photo credit: NASA/JPL/Space Science Institute

Ten New Lacus Named on Titan

From the USGS Astrogeology Science Center:

Ten names with the descriptor term lacus have been approved for use on Titan. For more information, see the list of Titan feature names and the map of the north polar region of Titan in the Gazetteer of Planetary Nomenclature.

Notes: The ten newly named lakes are (in alphabetical order): Albano Lacus, Atitlán Lacus, Cayuga Lacus, Junín Lacus, Lanao Lacus, Logtak Lacus, Ohrid Lacus, Sevan Lacus, Uvs Lacus, and Vänern Lacus. All names were approved on September 16, 2010. There are now a total of 24 named lakes on Titan.

A Brief Discontinuity in the Space-Time Continuum

This is a quick note to say that my home is going through some renovation work through early next week. Blogging is more or less halted until then, although, if I can find some time to do some posts, I'll try to put up some new material. In the meantime, please feel free to visit the archives of Areology, Ministry of Space Exploration, and Saturnology.

Atlas and F-Ring Shadows

Delicate shadows are cast outward from Saturn's thin F ring in the lower left of this image taken as the planet approached its August 2009 equinox.

The moon Atlas (30 kilometers, or 19 miles across) is seen just above the center of the image between the A ring and thin F ring. Several background stars are also visible.

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 8 degrees above the ringplane.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 11, 2009. The view was obtained at a distance of approximately 1.098 million kilometers (682,000 miles) from Atlas. Image scale is 7 kilometers (4 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Elephant Skin Enceladus

Two sources of light reveal the dramatic surface of Saturn's moon Enceladus in this Cassini image in which geologic features give the appearance of the leathery skin of an elephant.

Geologically young terrain in the southern and middle latitudes gives way to older, cratered terrain in the northern latitudes of the moon. See PIA11685 to learn more.

Sunlight illuminates the right of the image, and light reflected off Saturn dimly illuminates the left. This view looks toward the leading hemisphere of Enceladus (504 kilometers, or 313 miles across). North on Enceladus is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 7, 2010. The view was obtained at a distance of approximately 198,000 kilometers (123,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 92 degrees. Image scale is 1 kilometer (3,300 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Quartet and Crescent

Four of Saturn's moons join the planet for a well balanced portrait.

Saturn's largest moon, Titan (5,150 kilometers, or 3,200 miles across), is in the lower left. Tethys (1,062 kilometers, or 660 miles across) is in the upper right. Although those moons appear to be above and below the rings from this vantage point, the moons actually orbit nearly within the ringplane.

The smaller moons Pandora and Epimetheus are barely visible here. Pandora (81 kilometers, or 50 miles across) appears as a tiny speck on the extreme left, near the rings. Epimetheus (113 kilometers, or 70 miles across) can be detected above the rings near the middle left of the image. To enhance visibility, Pandora and Epimetheus have been brightened by a factor of two relative to the planet, rings, Titan and Tethys.

This view looks toward the southern, unilluminated side of the rings from about 3 degrees below the ringplane.

The image was taken with the Cassini spacecraft wide-angle camera on July 17, 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 2.5 million kilometers (1.6 million miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 104 degrees. Image scale is 147 kilometers (91 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Saturnian Trio

The F ring's shepherds, Prometheus and Pandora, join Epimetheus in this image of three of Saturn's moons and the rings.

Prometheus (86 kilometers, or 53 miles across) can be seen orbiting inside the thin F ring near the middle of the image. Pandora (81 kilometers, or 50 miles across) orbits outside the F ring to the left of Prometheus. Epimetheus (113 kilometers, or 70 miles across) orbits beyond the F ring near the bottom of the image.

See PIA07653 to learn more about how Prometheus and Pandora "shepherd" the F ring.

This view looks toward the southern, unilluminated side of the rings from about 2 degrees below the ringplane. Several background stars are visible.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on August 2, 2010. The view was acquired at a distance of approximately 2.5 million kilometers (1.6 million miles) from Prometheus and Pandora. The view was acquired at a distance of approximately 2.6 million kilometers (1.6 million miles) from Epimetheus. Image scale is 15 kilometers (9 miles) per pixel on Prometheus and Pandora. Image scale is 16 kilometers (10 miles) per pixel on Epimetheus.

Photo credit: NASA/JPL/Space Science Institute

Titan

The Cassini spacecraft examines Titan's dark and light seasonal hemispheric dichotomy as it images the moon with a filter sensitive to near-infrared light.

The southern hemisphere looks darker than the northern hemisphere using a spectral filter sensitive to wavelengths of near-infrared light centered at 889 nanometers. This image also shows Titan's north polar hood (see PIA08137 and PIA11594). See PIA11603 to learn more about the seasonal dichotomy.

This view looks toward the leading hemisphere of Titan (5,150 kilometers, or 3,200 miles across). North on Titan is up and rotated 2 degrees to the left.

The image was taken with the Cassini spacecraft narrow-angle camera on May 22, 2010. The view was obtained at a distance of approximately 1.1 million kilometers (684,000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 37 degrees. Image scale is 6 kilometers (4 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Saturnian Quartet

A quartet of Saturn's moons are shown with a sliver of the rings in this Cassini spacecraft view.

From left to right in this image are Epimetheus (113 kilometers, or 70 miles across), Janus (179 kilometers, or 111 miles across), Prometheus (86 kilometers, or 53 miles across) and Atlas (30 kilometers, or 19 miles across).

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 July 27, 2010. The view was obtained at a distance of approximately 1.3 million kilometers (808,000 miles) from Janus, Prometheus and Atlas. The view was obtained at a distance of approximately 1.2 million kilometers (746,000 miles) from Epimetheus. Image scale is 8 kilometers (5 miles) per pixel on Janus, Prometheus and Atlas. Image scale is 7 kilometers (4 miles) per pixel on Epimetheus.

Photo credit: NASA/JPL/Space Science Institute

Janus

Saturn's moon Janus shows the scars of impacts in this Cassini spacecraft image of craters light and dark.

This view looks toward the Saturn-facing side of Janus (179 kilometers, or 111 miles across). North on Janus is up and rotated 10 degrees to the right.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on April 7, 2010. The view was acquired at a distance of approximately 75,000 kilometers (47,000 miles) from Janus and at a Sun-Janus-spacecraft, or phase, angle of 39 degrees. Image scale is 448 meters (1,469 feet) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Enceladus

Saturn's moon Enceladus, imaged at high phase, shows off its spectacular water ice plumes emanating from its south polar region.

This image was captured at a phase, or Sun-Enceladus-spacecraft, angle of 159 degrees so that sunlight would reveal the backlit plumes. See PIA11688 to learn more.

Sunlight brightly illuminates terrain on the left. Light reflected off Saturn illuminates the rest of the moon more dimly. This view looks toward the trailing hemisphere of Enceladus (504 kilometers, or 313 miles across). North is up.

Background stars, elongated by the movement of the spacecraft during the exposure, are also visible.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on October 13, 2009. The view was obtained at a distance of approximately 431,000 kilometers (268,000 miles) from Enceladus. Image scale is 3 kilometers (2 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Janus Beyond the Rings

Saturn's rings appear curved in this Cassini spacecraft view, which also shows the moon Janus in the distance.

Janus (179 kilometers, or 111 miles across) is at the bottom of the image and is farther from the spacecraft than the rings are. Near the top of the image the rings appear curved because this view was captured using the narrow-angle camera to show a portion of the rings off the ansa and because Cassini is very near the ringplane.

This view looks toward the southern, unilluminated side of the rings from about 4 degrees below the ringplane. Several background stars are visible.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 20, 2010. The view was acquired at a distance of approximately 2.1 million kilometers (1.3 million miles) from Janus. Image scale is 13 kilometers (8 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute

Crescent Dione

A thin crescent of cratered terrain is illuminated on Saturn's third largest moon, Dione.

Lit terrain seen here is on the Saturn-facing side of Dione (1,123 kilometers, or 698 miles across). North is up.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 17, 2010. The view was acquired at a distance of approximately 394,000 kilometers (245,000 miles) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 151 degrees. Image scale is 2 kilometers (1 mile) per pixel.

Photo credit:

F-Ring Fan

The Cassini spacecraft spies a "fan" in Saturn's tenuous F ring.

This fan-like structure appears as dark lines spreading outward from the left of the bright clump of ring material near the center of the image. See PIA12784 and PIA12786 to learn more about fans.

This view looks toward the northern, sunlit side of the rings from about 10 degrees above the ringplane. Several background stars are visible, including two that can be seen through the ring.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on June 1, 2010. The view was acquired at a distance of approximately 1.3 million kilometers (808,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 119 degrees. Image scale is 7 kilometers (4 miles) per pixel.

Photo credit: NASA/JPL/Space Science Institute