| Ultimi arrivi - Saturn: the "Ringed Beauty" and His Moons |
Tethys-PIA07623.jpgTethys and Dione56 visiteOriginal caption:"Saturn's expansive Rings separate the moon's Tethys (at the top) from Dione (at the bottom). Even in this distant view, it is easy to see that the moons' surfaces, and likely their evolutionary paths, are very different.
Both moons are on the far side of the Rings in this scene, which shows their Saturn-facing Hemispheres (terrain centered on 0° Long.). The dark shadow across the rings is cast by Saturn's Southern Hemisphere.
Note that the diameter of Tethys is about 1.071 Km while the diameter of Dione is approx. 1.126 Km.
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 12, 2005, at a distance of approx. 2,4 MKM (such as about 1,5 MMs) from Saturn. The image scale is about 17 Km (about 11 miles) per pixel on the two moons".Nov 04, 2005
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Pandora-N00042203.jpgPandora and...?58 visiteOriginal caption:"N00042203.jpg was taken on October 29, 2005 and received on Earth October 30, 2005. The camera was pointing toward PANDORA at approximately 459.147 Km away, and the image was taken using the CL1 and UV3 filters. This image has not been validated or calibrated".Nov 02, 2005
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Pandora-N00042197.jpgPandora?71 visiteOriginal caption:"N00042197.jpg was taken on October 29, 2005 and received on Earth October 30, 2005. The camera was pointing toward PANDORA at approximately 455.248 Km away, and the image was taken using the CL1 and IR1 filters. This image has not been validated or calibrated".Nov 02, 2005
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Saturn-W00011753.jpgSaturn's limb59 visiteOriginal caption:"W00011753.jpg was taken on October 30, 2005 and received on Earth October 30, 2005. The camera was pointing toward SATURN at approximately 345.545 Km away, and the image was taken using the CL1 and BL1 filters. This image has not been validated or calibrated".Nov 01, 2005
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Tethys and Dione-PIA07621.jpgTethys and Dione58 visiteOriginal caption:"This image shows Tethys partially occulting Dione. For comparison purposes, we remind you that the diameter of Tethys is 1.071 Km (about 665 miles), while Dione is 1.126 Km (such as about 700 miles) across; the difference in the surface brightness of the two moons is immediately apparent.
This still image was acquired on Sept. 16, 2005, at a distance of 2,1 MKM (such as about 1,3 MMs) from Dione and 2,7 MKM (about 1,7 MMs) from Tethys. Resolution in the original images was 13 Km (approx. 8 miles) per pixel on Dione and 16 Km (approx. 10 miles) per pixel on Tethys.
The image was magnified by a factor of two to aid visibility of surface features".Nov 01, 2005
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Enceladus-PIA07619.jpgEnceladus over the B-Ring58 visiteOriginal caption:"The moon Enceladus seems to hover above the outer reaches of Saturn's B-Ring. Below and to the right of Enceladus, four faint bands lie in the center of the dark Cassini Division.
Recently, scientists have speculated that the particles that make up the dense B and A-Rings might be more like fluffy snowballs than hard ice cubes. The conclusion is based on temperature data obtained by the Cassini spacecraft.
Enceladus' diameter is about 505 Km (such as approx. 314 miles). The icy moon is on the near side of the Rings in this view.
This image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 15, 2005, at a distance of approx. 2,3 MKM (1,4 MMs) from Enceladus.
The image scale is 14 Km (approx. 9 miles) per pixel on Enceladus".Nov 01, 2005
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Dione-PIA07618.jpgCanyonland75 visiteOriginal caption:"The Cassini spacecraft views the far-off wispy canyons of Saturn's moon Dione and sees an interesting dichotomy between the bright wisps and the bright South Polar Region at the bottom. The view looks toward the trailing hemisphere on Dione. North is up.
The image was taken with the Cassini spacecraft's narrow-angle camera on Sept. 20, 2005, through a filter combination sensitive to polarized green light. The image was acquired at a distance of approx. 2,1 MKM (about 1,3 MMs) from Dione and at a Sun-Dione-spacecraft, or phase, angle of 64°. Resolution in the original image was 12 Km per pixel. The image has been magnified by a factor of two to aid visibility".
Nota: un'immagine "modesta" di Dione, ripresa da una grande distanza e che - stranamente - evidenzia davvero molto bene la "profondità" dei rilievi Dioniani. Curioso, trattandosi di un frame NON 3D.Ott 30, 2005
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The Rings-PIA07750.jpgSurfing the waves of the F-Ring (from 1,1 MKM)56 visiteOriginal caption:"This mosaic of 15 Cassini images of Saturn's F-Ring shows how the moon Prometheus creates a gore in the Ring once every 14 h and 42', as it approaches and recedes from the F-Ring on its eccentric orbit. The individual images have been processed to make the Ring appear as if it has been straightened, making it easier to see the Ring's structure. The mosaic shows a Region 147.000 Km (about 91.000 miles) along the Ring (horizontal direction in the image); this represents about 60° of Longitude around the Ring. The Region seen here is about 1500 Km (900 miles) across (vertical direction). The first and last images in the mosaic were taken approximately 2,5 hours apart.
Each dark channel, or "gore," is clearly visible across more than 1,000 kilometers (600 miles) of the ring and is due to the gravitational effect of Prometheus (102 kilometers, or 63 miles across), even though the moon does not enter the F ring. The channels have different tilts because the ring particles closer to Prometheus (overexposed, stretched, and just visible at the bottom right of the image) move slower with respect to the moon than those farther away. This causes the channels to shear with time, their slopes becoming greater, and gives the overall visual impression of drapes of ring material. The channels at the right are the youngest and have near-vertical slopes, while those at the left are the oldest and have near-horizontal slopes. This phenomenon has not previously been detected in any other planetary ring system, but computer simulations of the system prove that the disturbance is caused by a simple gravitational interaction. The eccentric orbit of Prometheus is gradually moving so that the moon will eventually come even closer in its closest approach to the eccentric F ring. Scientists calculate that its perturbations of the F ring will reach a maximum in December 2009".Ott 27, 2005
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The Rings-PIA07616.jpgThe "Cassini" Division (close-up)79 visiteOriginal caption:"The outer reaches of Saturn's Cassini Division merges with the inner A-Ring (at the right) in a Region that is rich in structure.
The smooth Region leading up to the A-Ring grows brighter from the left to the right (known as a "ramp" to Ring).
This Region contains a faint "double-wave" structure that is a density feature caused by the influence of the co-orbital moons Janus and Epimetheus. Scientists are interested in observing the evolution of this density wave as the moons swap places in their orbits every few years, presumably resulting in a change in the perturbations that cause this feature.
This image was taken in visible light with the Cassini narrow-angle camera on Sept. 5, 2005, at a distance of approx. 441.000 Km (about 274.000 miles) from Saturn. The image scale is 2 Km (a little more than 1 mile) per pixel".Ott 27, 2005
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Janus-PIA07615.jpgJanus and Epimetheus58 visiteOriginal caption:"Outside the soft edge of Cassini's F-Ring, Epimetheus and Janus negotiate their nearly-shared orbit. The two moons' orbits are typically about 50 Km (approx. 30 miles) apart, and the moons actually change orbits every few years: one moon becoming the innermost of the pair, the other becoming the outermost.
Epimetheus' diameter is 116 Km while Janus' diameter is 181 Km across.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 8, 2005, at a distance of approx. 1,5 MKM (about 1 MMs) from Saturn. The image scale is about 11 Km (roughly 7 miles) per pixel on the two moons".Ott 25, 2005
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Rhea-PIA07614.jpgMimas, Rhea and the Rings58 visiteOriginal caption:"The Saturn moon Mimas is much smaller than Rhea, but the geometry of this scene exaggerates the actual differences in size. Here, Mimas is on the opposite side of the rings from Rhea and Cassini. Saturn's shadow slices across the Ring-plane here.
The view looks toward the Saturn-facing hemisphere on Mimas and the anti-Saturn hemisphere on Rhea.
The image was taken in visible light with the narrow-angle camera on Sept. 9, 2005, from a distance of approx. 1,5 MKM (about 900.000 miles) from Rhea. Mimas was located on the far side of the Rings, such as about 670.000 Km (approx. 420.000 miles) farther from Cassini. The image scale is roughly 9 Km (about 6 miles) per pixel on Rhea and 13 Km (about 8 miles) per pixel on Mimas".Ott 25, 2005
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Saturn_s Sky-W00011343.jpgBright Stars in the sky of Saturn58 visiteOriginal caption:"W00011343.jpg was taken on October 23, 2005 and received on Earth October 24, 2005. The camera was pointing toward SATURN-E-RING at approximately 1.242.596 kilometers away and the image was taken using the CL1 and GRN filters. This image has not been validated or calibrated".
Nota: una sola cosa ci pare certa: questa non è un'immagine dell'Anello G di Saturno. Che cosa rappresenti...tiriamo ad indovinare: il Sole ed un Satellite Saturniano sovraesposto. Che ne dite? E' plausibile?!?Ott 25, 2005
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