| |
| Ultimi arrivi - Saturn: the "Ringed Beauty" and His Moons |
Hyperion-PIA14580-PCF-LXTT.jpgFeatures of Hyperion (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 214 visiteCaption NASA:"The sponge-like Surface of Saturn's moon Hyperion is highlighted in this Cassini portrait, captured during the Spacecraft's Sept. 16, 2011, Fly-By. Hyperion (which is about 168 miles, or approx. 270 Km across) has an irregular shape, and it tumbles through its orbit: that is, it does not spin at a constant rate or in a constant orientation. (A standard reference latitude-longitude system has not yet been devised for this moon.)
Images such as this one extend previous coverage and allow a better inventory of the surface features, the satellite's shape and changes in its spin.
The image was taken in Visible Blue Light with the Cassini Spacecraft narrow-angle camera. The view was obtained at a distance of approx. 55.000 miles (such as about 88.000 Km) from Hyperion and at a Sun-Hyperion-Spacecraft, or Phase, Angle of 37°.
Image scale is roughly 1720 feet (524 meters) per pixel".MareKromiumNov 03, 2011
|
|
Enceladus-PIA14858-PCF-LXTT.jpgFountains of Light (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team) 153 visiteCaption NASA:"NASA's Cassini Spacecraft successfully completed its Oct. 1st Fly-By of Saturn's moon Enceladus and its Jets of Water Vapor and Ice. At its closest approach, the Spacecraft flew approx. 62 miles (about 100 Km) above the moon's Surface. The close approach was designed to give some of Cassini's instruments, including the Ion and Neutral Mass Spectrometer, the chance to "taste" the Jets themselves.
At a higher vantage point during the encounter, Cassini's high-resolution camera captured pictures of the jets emanating from the moon's South Polar Region. The latest raw images of Enceladus are online at:
http://saturn.jpl.nasa.gov/photos/raw/.
The images of the Surface include previously seen Leading-Hemisphere Terrain. However, during this encounter, multi-spectral imaging of these Terrains extended farther into the UV Region of the Spectrum than had previously been achieved at this resolution.
By looking at the Surface at UV wavelengths, scientists can better detect the difference between surface materials and shadows than they can at visible wavelengths, where icy materials are highly reflective and shadows are washed out. With both UV and Visible Light images of the same Terrain available to them, scientists will better understand how the Surface coverage of icy particles coming from the Vents and Plumes changes with Terrain type and age. Cassini's next pass of this fascinating moon will be Oct. 19, 2011, when the Spacecraft shall fly-by at an altitude of approximately 765 miles (such as about 1231 Km)".MareKromiumOtt 11, 2011
|
|
Janus-PIA09872-PCF-LXTT.jpgCrescent Janus (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunar Explorer Italia)218 visiteCaption NASA:"The Cassini Spacecraft snapped this exquisite, close-up view of Saturn's moon Janus, looking toward the South Polar Region, on Feb. 20, 2008.
Janus is about 181 Km (approx. 113 miles) across.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera. The view was acquired at a distance of approx. 169.000 Km (such as about 105.000 miles) from Janus and at a Sun-Janus-Spacecraft, or phase, angle of 71°. Image scale is roughly 1 Km (about 0,6 mile) per pixel".
MareKromiumOtt 01, 2011
|
|
Rhea-PIA14574-PCF-LXTT.jpgRhea in the Saturnshine (Enhanced Absolute Natural Colors; credits for the additional process. and color: Dr Paolo C. Fienga - Lunexit Team)140 visiteCaption NASA:"Southern Terrain on Saturn's moon Rhea is dimly illuminated by Saturnshine in this Cassini Spacecraft view of the dark side of the moon. The Spacecraft's camera is looking toward the night side of Rhea, but sunlight reflected off the day side of immense Saturn is bright enough to illuminate the Craters seen here. This view is centered on Terrain located at about 23° South Latitude and 315° West Longitude. A few background stars are visible.
The image was taken in Visible Light with the Cassini Spacecraft wide-angle camera on Aug. 1, 2011. The view was obtained at a distance of approx. 6000 Km (such as about 3700 miles) from Rhea and at a Sun-Rhea-Spacecraft, or Phase, Angle of 113°. Scale in the original image was 800 meters (2600 feet) per pixel. The image was contrast enhanced and magnified by a factor of 1.5 to enhance the visibility of the surface features".MareKromiumSet 24, 2011
|
|
Hyperion-N00174824-N00174908-GB-LXTT.gifTumbling Hyperion (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)164 visitenessun commentoMareKromiumSet 04, 2011
|
|
Helene-PIA12779-PCF-LXTT.jpgLike a "Cosmic Apple"... (Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunar Explorer Italia)135 visiteCaption NASA:"Saturn's small, irregularly shaped moon Helene is strikingly illuminated in this close view captured by Cassini during the Spacecraft's June 18, 2011, Fly-By. Although it is not visible at this exposure, the Planet (Saturn?) actually fills the dark background of this image of Helene.
This view looks toward the anti-Saturn side of Helene (which is about 33 Km, or approx. 21 miles across). North on Helene is up. The lit Terrain on the right is on the Leading Hemisphere, while lit Terrain at the top of the image surrounds the North Pole.
This image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera. The view was obtained at a distance of approximately 11,000 kilometers (7,000 miles) from Helene and at a Sun-Helene-Spacecraft, or Phase, Angle of 151°.
Image scale is roughly 67 meters (220 feet) per pixel".MareKromiumAgo 17, 2011
|
|
Saturn_and_Moons-N00173684_-83-82-MF-LXTT.jpgTrue Planets (Absolute Natural Colors; credits for the additional process. and color.: Dr Marco Faccin - Lunexit Team)174 visitenessun commentoMareKromiumAgo 04, 2011
|
|
Saturn-PIA12824.jpgSaturnian Storm (Natural Colors; credits: NASA/JPL-Caltech/Space Science Institute)65 visiteCaption NASA:"The huge storm churning through the Atmosphere in Saturn's Northern Hemisphere overtakes itself as it encircles the Planet in this Natural Colors view from NASA's Cassini Spacecraft.
This picture, captured on Feb. 25, 2011, was taken about 12 weeks after the storm began, and the clouds by this time had formed a tail that wrapped around the Planet. Some of the clouds moved south and got caught up in a current that flows to the East (to the right) relative to the storm head. This tail, which appears as slightly blue clouds South and West (left) of the storm head, can be seen encountering the storm head in this view.
This storm is the largest, most intense storm observed on Saturn by NASA's Voyager or Cassini Spacecraft. It is still active today. As scientists have tracked this storm over several months, they have found it covers 500 times the area of the largest of the Southern Hemisphere storms observed earlier in the Cassini Mission (see PIA06197).
The shadow cast by Saturn's Rings has a strong seasonal effect, and it is possible that the switch to powerful storms now being located in the Northern Hemisphere is related to the change of seasons after the Planet's August 2009 Equinox.
Huge storms called Great White Spots have been observed in previous Saturnian years (each of which is about 30 Earth years), usually appearing in late Northern Summer. Saturn is now experiencing early Northern Spring, so this storm, if it is a Great White Spot, is happening earlier than usual. This storm is about as large as the largest of the Great White Spots, which also encircled the planet but had latitudinal sizes ranging up to approx. 20.000 Km (roughly 12.000 miles). The Voyager and Cassini Spacecrafts were not at Saturn for previous Great White Spot appearances.
The storm is a prodigious source of radio noise, which comes from lightning deep in the Planet's Atmosphere. The lightning is produced in the water clouds, where falling rain and hail generate electricity. The mystery is why Saturn stores energy for decades and releases it all at once. This behavior is unlike that at Jupiter and Earth, which have numerous storms going on at all times.
This view looks toward the 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 acquired with the Cassini Spacecraft wide-angle camera at a distance of approx. 1,4 MMs (such as about 2,2 MKM) from Saturn. Image scale is roughly 80 miles (128,7472 Km) per pixel".MareKromiumLug 17, 2011
|
|
Saturn-PIA12825.jpgSaturnian Storm (False Colors; credits: NASA/JPL-Caltech/Space Science Institute)64 visiteCaption NASA:"These false-color images from NASA's Cassini Spacecraft chronicle a day in the life of a huge storm that developed from a small spot that appeared 12 weeks earlier in Saturn's Northern Mid-Latitudes.
This storm is the largest and most intense observed on Saturn by NASA's Voyager or Cassini Spacecraft. The storm is still active. As seen in these and other Cassini images, the storm encircles the Planet - whose circumference at these latitudes is approx. 186.000 miles (about 300.000 Km).
From North to South, it covers a distance of about 9000 miles (approx. 15.000 Km), which is one-third of the way around the Earth. It encompasses an area of about 1,5 BSMs (Billion Square Miles - such as approx. 4 BSKM), or eight times the surface area of Earth. This storm is about 500 times the area of the biggest of the Southern Hemisphere storms observed by Cassini.
The highest clouds in the image are probably around 100 millibars pressure, or 60 miles (approx. 100 Km) above the regular undisturbed clouds. These false colors show clouds at different altitudes. Clouds that appear blue here are the highest and are semitransparent, or optically thin. Those that are yellow and white are optically thick clouds at high altitudes. Those shown green are intermediate clouds. Red and brown colors are clouds at low altitude unobscured by high clouds, and the deep blue color is a thin haze with no clouds below. The base of the clouds, where lightning is generated, is probably in the water cloud layer of Saturn's Atmosphere. The storm clouds are likely made out of Water Ice covered by crystallized Ammonia.
Taken about 11 hours -- or one Saturn day -- apart, the two mosaics in the lower half of this image product consist of 84 images each. The mosaic in the middle was taken earlier than the mosaic at the bottom. Both mosaics were captured on Feb. 26, 2011, and each of the two batches of images was taken over about 4,5 hours.
Two enlargements from the earlier, middle mosaic are shown at the top of this product. The white lines below the middle mosaic identify those parts of the mosaic that were enlarged for these close-up views. The enlargement on the top left shows the head of the storm, and that on the top right shows the turbulent middle of the storm. Cassini observations have shown the head of the storm drifting West at a rate of about 2,8° of Longitude each Earth day (28 meters per second, or 63 miles per hour). The central latitude of the storm is the site of a Westward jet, which means that the clouds to the North and South are drifting Westward more slowly or even drifting eastward. In contrast, clouds at Saturn's Equator drift Eastward at speeds up to 450 meters per second (about 1000 miles per hour).
Both of the long mosaics cover an area ranging from about 30° to 51° North Latitude. The views stretch from about 138° (on the left) to 347° West Longitude (on the right), passing through 360/0° West Longitude near the far right of the mosaics.
The images were taken with the Cassini Spacecraft narrow-angle camera using a combination of spectral filters sensitive to wavelengths of Near-InfraRed light. The images filtered at 889 nanometers are projected as blue. The images filtered at 727 nanometers are projected as green, and images filtered at 750 nanometers are projected as red.
The views were acquired at a distance of approx. 1,5 MMs (such as about 2,4 MKM) from Saturn and at a Sun-Saturn-Spacecraft Angle (i.e.: Phase Angle) of 62°. Both the top and bottom images are simple cylindrical map projections, defined such that a square pixel subtends equal intervals of Latitude and Longitude. At higher Latitudes, the pixel size in the North-South direction remains the same, but the pixel size in the East-West direction becomes smaller. The pixel size is set at the Equator, where the distances along the sides are equal. The images of the long mosaics have a pixel size of 33 miles (53,108 Km) at the Equator, and the two close-up views have a pixel size of 6 miles (9,656 Km) per pixel at the equator".MareKromiumLug 17, 2011
|
|
Saturn-PIA12826.jpgSaturnian Storm (Natural Colors; credits: NASA/JPL-Caltech/Space Science Institute)68 visitenessun commentoMareKromiumLug 17, 2011
|
|
Janus-PCF-LXTT.jpgJanus (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit team)89 visitenessun commentoMareKromiumGiu 29, 2011
|
|
Helene-N00172780-N00172904-GB-LXTT.gifFlying around Helene (a GIF-Movie by Dr Gianluigi Barca - Lunexit Team)223 visitenessun commentoMareKromiumGiu 22, 2011
|
|
| 2245 immagini su 188 pagina(e) |
|
|
|
|
6 | |
|
|
|
|
|
|
|
