Saturn: the "Ringed Beauty" and His Moons
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Mimas-N00124650.jpgMimas and the Giant behind... (possible True Colors; credits: Lunar Explorer Italia)58 visiteCaption NASA:"N00124650.jpg was taken on November 26, 2008 and received on Earth November 27, 2008. The camera was pointing toward MIMAS that, at the time, was approx. 914.921 Km away
The image was taken using the CL1 and CL2 filters".MareKromium
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Mimas-PIA01968.jpgMimas from Cassini/Huygens57 visiteMimas, in questo recente frame, sembra aver distolto il suo "sguardo" da noi e pare guardare verso l'alto, in una zona di cielo che non possiamo vedere. Ricollegandoci al commento che si faceva in precedenza, a proposito delle tecnologie possedute dal Voyager in rapporto a quelle disponibili per Cassini-Huygens, dobbiamo dire che questa immagine è sicuramente bella e chiara, ma NON più bella e più chiara di quella ottenuta dal Voyager 1 vent'anni fa!
C'è di che meditare, non è vero?!?
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Mimas-PIA06142_modest.jpgMimas and Saturn in real colors61 visiteCaption NASA originale:"In a splendid portrait created by light and gravity, Saturn's lonely moon Mimas is seen against the cool, blue-streaked backdrop of Saturn's northern hemisphere. Delicate shadows cast by the rings arc gracefully across the planet, fading into darkness on Saturn's night side. The bright blue swath near Mimas is created by sunlight passing through the Cassini division (4.800 Km wide). The rightmost part of this distinctive feature is slightly overexposed and therefore bright white in this image. Shadows of several thin ringlets within the division can be seen here as well. The dark band that stretches across the center of the image is the shadow of Saturn's B-Ring, the densest of the main rings. Part of the actual Cassini division appears at the bottom, along with the A-Ring and the narrow, outer F-Ring. The A-Ring is transparent enough that, from this viewing angle, the atmosphere and threadlike shadows cast by the inner C-Ring are visible through it".
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Mimas-PIA06176.jpgBlue Saturn and Mimas55 visiteCaption NASA originale:"Mimas drifts along in its orbit against the azure backdrop of Saturn's northern latitudes in this true color view. The long, dark lines on the atmosphere are shadows cast by the planet's rings.
Saturn's northern hemisphere is presently relatively cloud-free, and rays of sunlight take a long path through the atmosphere. This results in sunlight being scattered at shorter (bluer) wavelengths, thus giving the northernmost latitudes their bluish appearance at visible wavelengths.
At the bottom, craters on icy Mimas (398 Km or 247 miles across) give the moon a dimpled appearance.
Images taken using infrared (930 nanometers), green (568 nanometers) and ultraviolet (338 nanometers) spectral filters were combined. The colors have been adjusted to match closely what the scene would look like in natural color. The images were obtained using the Cassini spacecraft narrow angle camera on Jan. 18, 2005, at a distance of approx. 1,4 MKM from Saturn".
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Mimas-PIA06256.jpgMimas: spectacular overview54 visiteThe most detailed images ever taken of Saturn's moon Mimas show it to be one of the most heavily cratered Saturnian moons, with little (if any) evidence for internal activity. Mimas has been so heavily cratered that new impacts can only overprint or even completely obliterate other older craters. Mimas is about 397 Km across.
The moon displays an unexpected array of crater shapes. The highest crater walls tower 6 Km above the floors and show signs of material sliding down slope. Indeed, many of the large craters - more than 15 Km in diameter - appear to be filled in with rough-surfaced material, likely the result of landslides triggered by subsequent impacts elsewhere on Mimas' surface. Some of these deposits have craters superimposed on them, demonstrating that the landslides themselves may be quite old.
Grooves, some of which are over a Km deep, cut across the surface for more than 100 Km. These are some of the only indications that there might have once been internal activity under this ancient, battered surface.
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Mimas-PIA06257.jpgMimas: surface geology through "false colors"53 visiteThe image at the left is a narrow angle clear-filter image, which was separately processed to enhance the contrast in brightness and sharpness of visible features. The image at the right is a color composite of narrow-angle ultraviolet, green, infrared and clear filter images, which have been specially processed to accentuate subtle changes in the spectral properties of Mimas' surface materials. To create this view, 3 color images (ultraviolet, green and infrared) were combined into a single black and white picture that isolates and maps regional color differences. This "color map" was then superimposed over the clear-filter image at the left.
The combination of color map and brightness image shows how the color differences across the Mimas surface materials are tied to geological features.
Shades of blue and violet in the image at the right are used to identify surface materials that are bluer in color and have a weaker infrared brightness than the average Mimas materials (green).
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Mimas-PIA06258.jpgThe "Eye of Mimas": Herschel Crater53 visiteCaption NASA originale:"During its approach to Mimas on Aug. 2, 2005, the Cassini spacecraft narrow-angle camera obtained multi-spectral views of the moon from a range of 228.000 Km (about 142.500 miles).
This image is a narrow angle clear-filter image which was processed to enhance the contrast in brightness and sharpness of visible features.
Herschel Crater, a 140-kilometer-wide impact feature with a prominent central peak, is visible in the upper right of this image.
This image was obtained when the Cassini spacecraft was above 25° South, 134° West latitude and longitude. The Sun-Mimas-spacecraft angle was 45° and North is at the top".
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Mimas-PIA06259.jpgMimas: surface geology through "false colors" (Herschel Crater)53 visiteHerschel Crater, a 140-Km-wide (about 88 miles) impact feature with a prominent central peak, is visible in the upper right of each image. The unusual bluer materials are seen to broadly surround Herschel Crater. However, the bluer material is not uniformly distributed in and around the Crater. Instead, it appears to be concentrated on the outside of the Crater and more to the West than to the North or South.
The origin of the color differences is not yet understood. It may represent ejecta material that was excavated from inside Mimas when the Herschel impact occurred.
The bluer color of these materials may be caused by subtle differences in the surface composition or the sizes of grains making up the icy soil.
The images were obtained when the Cassini spacecraft was above 25°South, 134° West latitude and longitude.
The Sun-Mimas-spacecraft angle was 45° and North is at the top.
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Mimas-PIA06412.jpgMimas and the Rings53 visiteCaption NASA originale:"During its close flyby of Saturn's moon Mimas on Aug. 2, 2005, Cassini caught a glimpse of Mimas against the broad expanse of Saturn's Rings. The Keeler Gap in the outer A-Ring, in which Cassini spied a never-before-seen small moon, is at the upper right.
The ancient, almost asteroid-like surface of Mimas is evident in its crater-upon-crater appearance. Even the material which has slumped down into the bottom of some of its craters bears the marks of later impacts.
This image was taken through the clear filter of the Cassini spacecraft narrow-angle camera at a distance of 68.000 Km (about 42.500 miles) from Mimas and very near closest approach. The smallest features seen on the moon are about 400 mt wide (approx. 440 yards); the Sun-Mimas-Cassini angle is 44°".
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Mimas-PIA06582.jpgMimas's "Eye": the "Herschel Crater"56 visiteCaption NASA originale:"Saturn's moon Mimas has many large craters, but its Herschel Crater dwarfs all the rest. This large crater 130 Km wide (80 miles) has a prominent central peak, seen here almost exactly on the terminator. This crater is the moon's most prominent feature, and the impact that formed it probably nearly destroyed Mimas. Mimas is 398 Km (247 miles) across. This image was taken with the Cassini spacecraft narrow angle camera on Jan. 16, 2005, at a distance of approximately 213.000 Km (132.000 miles) from Mimas and at a phase angle of 84°. Resolution in the original image was about 1,3 Km (0,8 mi.s) per pixel. A combination of spectral filters sensitive to ultraviolet and polarized light was used to obtain this view. Contrast was enhanced and the image was magnified by a factor of two to aid visibility".
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Mimas-PIA06591.jpg"Phase-locked" Mimas!54 visiteCaption NASA originale:"Cassini's ability to remain precisely and steadily pointed at targets, such as Saturn's moon Mimas (seen here) yields sharp images despite the relatively high speed at which the spacecraft moves.
Cassini was traveling at more than 13 Km per second when it acquired this view, which shows crisp detail on Mimas against the backdrop of Saturn's Northern Hemisphere. Shadows of the icy rings stretch across the atmosphere and appear to be blurred because of the spacecraft motion.
The part of Mimas visible here always faces away from Saturn as the moon orbits the Gas Giant. In scientific language (jargon...), Mimas is said to be "phase-locked".
The image has been rotated so that North on Mimas (and Saturn) is up. This view was obtained with the Cassini spacecraft narrow angle camera on Jan. 18, 2005, at a distance of approx. 1,25 MKM from Mimas and at a phase angle of 114°. The image was taken using filters sensitive to wavelengths of infrared and polarized light. Res. is 7 Km/pixel".
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Mimas-PIA06642.jpgMimas, Dione and Rhea56 visiteCaption NASA originale:"A scene straight out of science fiction, this fantastic view shows, from left to right, Saturn's moon's Mimas, Dione and Rhea, on the far side of Saturn's nearly edge-on rings.
The trailing hemispheres of all three moons are sunlit here and wispy markings can be seen on the limbs of both Dione and Rhea. The image was taken in visible blue light with the Cassini spacecraft narrow-angle camera on March 15, 2005, at a distance of approximately 2,4 mkm (approx. 1,5 MMs) from Saturn.
The image scale is 14 Km (approx. 9 miles) per pixel".
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