| Ultimi arrivi - Saturn: the "Ringed Beauty" and His Moons |
Japetus-N00056228.jpgA little slice of light...56 visiteCaption originale:"N00056228.jpg was taken on April 01, 2006 and received on Earth April 02, 2006. The camera was pointing toward Iapetus that, at the time, was approximately 1.867.469 Km away, and the image was taken using the CL1 and IR1 filters".Apr 03, 2006
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Atlas-PIA08147.jpgAtlas57 visiteCaption NASA originale:"The Cassini spacecraft looks up from beneath the ringplane to spy Atlas, hugging the outer edge of the A-Ring, above center.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 23, 2006, at a distance of approx. 1,1 MKM (such as about 700.000 miles) from Atlas (32 Km, or 20 miles across).
The image scale is roughly 7 Km (about 4 miles) per pixel on Atlas".Apr 02, 2006
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Rhea-PIA08146.jpgRhea and the Rings59 visiteCrater-scarred Rhea floats in the distance, peeking out from behind Saturn's partly shadowed Rings. This view looks upward from just beneath the Ring-Plane. The far side of the Rings is masked by Saturn's shadow.
The North Pole of Rhea is obscured by part of the A-ring and the sharply defined F-Ring.
A few bright wispy markings curl around the eastern limb of Rhea.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Feb. 22, 2006, at a distance of approx. 2,2 MKM (about 1,4 MMs) from Rhea. The image scale is about 13 Km (roughly 8 miles) per pixel on Rhea.Mar 31, 2006
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Propellers-003-PIA07791.jpgThe "Propellers" of the Rings (4) - HR (detail mgnf)57 visiteThis magnified view illustrates the general orientation of the Propellers in Saturn's Rings, as they orbit around the Planet.
The two dashes of the Propeller are oriented in the direction of orbital motion. The "leading" dash is also slightly closer to Saturn; this "radial offset" is about 300 mt (about 1000 feet). The unseen moonlet lies in the center of the structure.
The grainy appearance of the image is due to magnification and the fact that the Propellers are very faint - just visible above the level of the back-ground noise. Consequently, the image enhancement procedures used to create this detail mgnf, have also enhanced the noise.Mar 30, 2006
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Propellers-002-PIA07790.jpgThe "Propellers" of the Rings (3) - HR55 visiteThe Propellers are about 5 Km (approx. 3 miles) long from tip to tip, and the radial offset (the "leading" dash is slightly closer to Saturn) is about 300 mt (about 1000 feet).
The Propellers structures are unchanged as they orbit around Saturn.
In that way, they are much like the wave pattern that trails after a speedboat as it skims across a smooth lake. Such a pattern is hard to discern in a choppy sea (---> mare increspato). In much the same way, scientists think other effects may be preventing Cassini from seeing the Propellers except in very bland parts of the Rings.Mar 30, 2006
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Propellers-001-PIA07792.jpgThe "Propellers" of the Rings (2) - HR55 visiteThis image is a closer view of the A-Ring, showing the radial locations where "Propeller Features" were spotted. The view is approx. 1.800 Km across (such as about 1.100 miles), from top to bottom, and includes a large density wave at the bottom (caused by the moons Janus and Epimetheus), as well as two smaller density waves.
The footprints of the Propellers are between density waves, in bland, quiescent regions of the Ring.
The Propellers appear as double dashes in the two close-up discovery images and they have been circled. The unseen moonlets, each roughly the size of a football field, lie in the center of each structure. These two images were taken during Saturn orbit insertion on July 1, 2004, and are presented here at one-half scale. Resolution in the original images was 52 mt (about 171 feet) per pixel.
The horizontal lines in the image represent electronic noise and do not correspond to any actual Ring features.Mar 30, 2006
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Propellers-000-PIA07792.jpgThe "Propellers" of the Rings (1) - HR57 visiteThis collection of 3 Cassini images provides context for understanding the location and scale of some "propeller-shaped features" observed within Saturn's A-Ring.
Careful analysis of the HR images taken by Cassini's cameras as the spacecraft slipped into Saturn orbit revealed the 4 faint, propeller-shaped double-streaks in an otherwise bland part of the mid A-Ring. Imaging scientists believe the "propellers" provide the first direct observation of the dynamical effects of moonlets which are approx. 100 mt (such as about 300 feet) in diameter.
The propeller moonlets represent a so far unseen size-class of particles orbiting within the Rings.
The 2nd panel provides broad context within the Rings, and shows the B-Ring, the Cassini Division, the A-Ring and the F-Ring. Image scale in the radial, or outward from Saturn, direction is about 45 Km (about 28 miles) per pixel; because the Rings are viewed at an angle, the image scale in the longitudinal - or circumferential - direction is several times greater.Mar 30, 2006
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Saturn-PIA08143.jpgThe texture of the Rings and Northern Regions of Saturn58 visiteShadows drape Saturn's Northern Hemisphere, providing a different kind of look at prominent features in the Rings. From the lower left corner upward, the visible features are: the shadow of the outer B-Ring, followed by the wide, bright Cassini Division, then the A-Ring with the embedded thin, bright Encke Gap and finally the dark, narrow, F-Ring.
The image was taken with the Cassini spacecraft narrow-angle camera on Feb. 18, 2006, using a filter sensitive to wavelengths of infrared light centered at 750 nnmts, and at a distance of approx. 2,8 MKM (such as about 1,7 MMs) from Saturn. The image scale is roughly 16 Km (about 10 miles) per pixel.Mar 29, 2006
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Rhea&Dione-N00056096.jpgIn-transit: Dione and Rhea (10)56 visitenessun commentoMar 29, 2006
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Rhea&Dione-N00056095.jpgIn-transit: Dione and Rhea (9)59 visitenessun commentoMar 29, 2006
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Rhea&Dione-N00056094.jpgIn-transit: Dione and Rhea (8)58 visitenessun commentoMar 29, 2006
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Rhea&Dione-N00056093.jpgIn-transit: Dione and Rhea (7)56 visitenessun commentoMar 29, 2006
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