Saturn: the "Ringed Beauty" and His Moons
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Saturn-PIA06532_modest.jpgSaturn from 618.000 Km54 visiteCaption NASA originale:"Cassini pierced the ring plane and rounded Saturn on Oct. 27, 2004, capturing this view of the dark portion of the rings. A portion of the planet's atmosphere is visible here, as is its shadow on the surface of the rings.
The image was taken with the Cassini spacecraft wide angle camera on Oct. 27, 2004, at a distance of about 618.000 Km from Saturn through a filter sensitive to wavelengths of infrared light centered at 1001 nanometers. The image scale is 33 Km per pixel".
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Saturn-PIA06538_modest.jpgSaturn and the shadow of his Rings54 visiteThis majestic view of Saturn captures several phenomena of interest to scientists working on the Cassini mission. The planet's nighttime atmosphere looms ahead - an excellent place to search for storms and lightning. Saturn's shadow stretches across the rings, which will over the next four years receive their most thorough examination since Galileo discovered them in 1610. And barely visible near lower right just inside the F-Ring, is the small shepherd moon Prometheus (102 Km across). Researchers will explore the many moons of Saturn, including special ones like Prometheus that help maintain some of the rings and gaps in this complex and dynamic system.
The image was taken in visible light with the Cassini spacecraft wide angle camera on Oct. 29, 2004, at a distance of about 940.000 Km from Saturn. The image scale is 52 Km per pixel."
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Saturn-PIA06604.jpgSaturn, Titan, Rhea and Enceladus55 visiteCaption NASA originale:"Saturn's biggest and brightest moons are visible in this portrait by Cassini.
Titan (5.150 Km, or 3,200 miles across) is Saturn's largest moon and appears at the lower left. Note that some details in the moon's smoggy atmosphere are visible here. Rhea (1.528 Km, or 949 miles across) is the planet's second largest moon and is seen above center. Enceladus (505 Km, or 314 miles across) has the brightest surface in the solar system, reflecting nearly all of the sunlight that falls upon it. Enceladus is just above the rings, left of center. Titan was on the far side of the planet at the time of this exposure, while the other moons were on the near side, much closer to Cassini.
Also seen here are details in the cloud bands of Saturn's mostly hydrogen atmosphere, variations in brightness across the dazzling rings and magnificent ring shadows cast upon the northern hemisphere. The image was taken with the Cassini spacecraft wide-angle camera on Feb. 5, 2005, at a distance of approximately 3.4 million kilometers (2.1 million miles) from Saturn through a filter sensitive to wavelengths of infrared light centered at 728 nanometers. The image scale is 200 kilometers (124 miles) per pixel".
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Saturn-PIA06619.jpgThe Southern Side of Saturn54 visiteCaption NASA originale:"Viewed nearly edge-on, Saturn's rings appear dark and pencil-thin against the backdrop of the planet's swirling clouds. Notable here are the shadows cast by the rings onto the northern hemisphere, as well as details of the banded atmosphere, such as the bright equatorial region. The image was taken with the Cassini spacecraft wide-angle camera on Feb. 18, 2005, at a distance of approximately 1,2 MKM from Saturn through a filter sensitive to wavelengths of infrared light centered at 727 nnmts, where gaseous methane absorbs. The image scale is 67 Km per pixel".
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Saturn-PIA06658.jpgSunlit South...54 visiteCaption NASA originale:"This poetic wide-angle camera view of Saturn reveals several small, dark storms in the southern latitudes, where storm activity has been prevalent since before Cassini arrived in orbit.
Also notable here is the semi-transparent C-Ring, which is visible against the backdrop of the planet.
The image was taken in visible light with the Cassini spacecraft wide-angle camera on April 23, 2005, through a filter sensitive to wavelengths of infrared light centered at 1028 nnmts and at a distance of approx. 2,4 MKM (about 1,5 MMs) from Saturn. The image scale is 142 Km (approx. 88 miles) per pixel".
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Saturn-PIA07008.jpgSaturn's temperature emissions (upper troposphere)55 visiteCaption NASA originale:"This is the sharpest image of Saturn's temperature emissions taken from the ground; it is a mosaic of 35 individual exposures made at the W.M. Keck I Observatory, Mauna Kea, Hawaii on Feb. 4, 2004.
The images to create this mosaic were taken with infrared radiation. The mosaic was taken at a wavelength near 17,65 microns and is sensitive to temperatures in Saturn's upper troposphere. The prominent hot spot at the bottom of the image is right at Saturn's South Pole. The warming of the Southern Hemisphere was expected, as Saturn was just past Southern Summer Solstice, but the abrupt changes in temperature with latitude were NOT expected. The tropospheric temperature increases toward the pole abruptly near 70° latitude from 88° to 89° Kelvin (-301° to -299° Fahrenheit) and then to 91° Kelvin (-296° degrees Fahrenheit) right at the Pole. Ring particles are not at a uniform temperature: they are obviously coldest just after having cooled down in Saturn's shadow (lower left)".
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Saturn-PIA07545.jpgSaturn and Tethys54 visiteCaption NASA originale:"The majesty of Saturn overwhelms in this image from Cassini. Saturn's moon Tethys glides past in its orbit and the icy rings mask the frigid northern latitudes with their shadows. The image was taken in visible green light with the Cassini spacecraft wide-angle camera on June 10, 2005, at a distance of approx. 1,4 MKM (about 900.000 miles) from Saturn. The image scale is 80 Km (about 50 miles) per pixel".
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Saturn-PIA07559.jpgRings in the Rings, both cut by the darkness...54 visiteCaption NASA originale:"This view shows the unlit face of Saturn's Rings, visible via scattered and transmitted light. In these views, dark regions represent gaps and areas of higher particle densities, while brighter regions are filled with less dense concentrations of ring particles.
The dim right side of the image contains nearly the entire C-Ring. The brighter region in the middle is the inner B-Ring, while the darkest part represents the dense outer B-Ring. The Cassini Division and the innermost part of the A-Ring are at the upper-left.
Saturn's shadow carves a dark triangle out of the lower right corner of this image.
The image was taken in visible light with the Cassini spacecraft wide-angle camera on June 8, 2005, at a distance of approximately 433.000 Km (about 269.000 miles) from Saturn. The image scale is 22 Km (about 14 miles) per pixel".
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Saturn-PIA07560.jpgSaturn and Tethys54 visiteOriginal caption:"Saturn poses with Tethys in this Cassini view. The C ring casts thin, string-like shadows on the Northern Hemisphere. Above that lurks the shadow of the much denser B-Ring. Cloud bands in the atmosphere are subtly visible in the south. Tethys is 1071 Km (about 665 miles) across.
Cassini will perform a close flyby of Tethys on Sept. 24, 2005. This image was taken on June 10, 2005, in visible green light with the Cassini spacecraft wide-angle camera at a distance of approx. 1,4 MKM (such as about 900.000 miles) from Saturn. The image scale is 81 Km (about 50 miles) per pixel".
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Saturn-PIA07562.jpgThe "anti-hurricanes" of Saturn54 visiteVortices mingle amidst other turbulent motions in Saturn's atmosphere in these two comparison images. The image on the right was taken about two Saturn rotations after the image on the left.
Both views show latitudes from -23° to -42°. The region below center in these images (at -35°) has seen regular storm activity since Cassini first approached Saturn in early 2004.
Cassini investigations of the atmosphere from February to October 2004 showed that most of the oval-shaped storms in the latitude region near -35° rotate in a counter-clockwise direction, with smaller storms occasionally merging into larger ones.
On Earth, hurricanes in the Southern Hemisphere rotate clockwise. Thus, the storms in these images of Saturn's southern latitudes could be called "anti-hurricanes."
This backwards spiraling (compared to Earth) is common on the giant planets.
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Saturn-PIA07563.jpgSaturn or Van Gogh?53 visiteSaturn's turbulent atmosphere is reminiscent of a Van Gogh painting in this view. However, unlike the famous impressionist painter, Cassini records the world precisely as it appears to the spacecraft's cameras.
The feathery band that cuts across from the upper left corner to the right side of this scene has a chevron, or arrow, shape near the right. The center of the chevron is located at the latitude (about 28° South) of an eastward-flowing zonal jet in the atmosphere. Counter-flowing eastward and westward jets are the dominant dynamic features seen in the giant planet atmospheres. A chevron-shaped feature with the tip pointed East means that this is a local maximum in the eastward wind and a region of horizontal wind shear where clouds to the North and South of the jet are being swept back by the slower currents on the sides of the jet.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 6, 2005, at a distance of approx. 2,5 MKM from Saturn using a filter sensitive to wavelengths of infrared light centered at 727 nanometers. The image scale is 14 kilometers (9 miles) per pixel.
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Saturn-PIA07568.jpgThe "dusty" D-Ring of Saturn54 visiteOriginal caption:"This close-up view is Cassini's best look yet at Saturn's tenuous innermost D-Ring. The narrow ringlet visible here is named D68 and is the innermost discrete feature in the D-Ring.
This image also clearly shows how the diffuse component of the D-Ring tapers off as it approaches the Planet.
The view is looking down on the dark side of the Rings, with the Planet's lower half being illuminated by reflected light from the Rings. The upper half of the Planet is also dark. The image was taken at a high phase angle - such as the Sun-Saturn-spacecraft angle - such as 177°. Viewing the Rings at high phase angle makes the finest dusty particles visible.
The inner edge of the C-Ring enters the scene at the lower left and Saturn's shadow cuts off the view of the Rings. Several background stars can also be seen here.
The image was taken in visible light with the Cassini spacecraft wide-angle camera on July 15, 2005, at a distance of approx. 293.000 Km from Saturn".
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