| Piú votate - Saturn: the "Ringed Beauty" and His Moons |
Saturn-PIA12318.jpgCosmic Vision (Natural Colors; credits: NASA/JPL/Space Science Institute)60 visiteCaption NASA:"Looking cool and serene, Saturn shares its soft glow with Cassini. This view of Saturn, its Rings and the moon Tethys represents "Target 1" in the fall 2009 edition of the Cassini Scientist for a Day contest.
(See http://saturn.jpl.nasa.gov/education/scientistforaday8thedition/.) The contest is designed to give students a taste of life as a scientist by challenging them to write an essay describing the value of one target choice among three for Cassini to image.
A bonus feature in the image is the presence of bright Spokes on and just above the ansa, or curved edge of the darkened Ring-Plane. The Spokes are made visible here by sunlight scattering through the dust-sized icy particles and toward Cassini's cameras.
Images taken using red, blue and green spectral filters were combined to create this color view.
The images were acquired with the Cassini wide-angle camera on Oct. 11, 2009 at a distance of approx. 1,7 MKM (a little more than 1 MMs) from Saturn".
Nota Lunexit: la dizione "Natural" l'abbiamo aggiunta noi, dato che la NASA - curiosamente - parla solo di "Color View" (insomma, adesso non fanno più nemmeno la fatica di dirci se si tratta di Natural, Approximate True, True e/o False Colors...bah!).MareKromium
(4 voti)
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Janus-PIA11597.jpgJanus (Natural - but enhanced - Colors; credits: Lunexit)59 visiteCaption NASA:"The Cassini Spacecraft looks toward the South Pole and cratered surface of Saturn's moon Janus.
The Pole of Janus lies on the Terminator, about one-third of the way inward from the bottom of the image. This view is centered on terrain at 42° South Lat. and 32° West Long.; the lit Terrain seen here is on the Saturn-facing side of Janus.
The image was taken in visible light with the Cassini Spacecraft narrow-angle camera on July 26, 2009. The view was acquired from a distance of approx. 100.000 Km (i.e. about 62.000 miles) from Janus and at a Sun-Janus-Spacecraft, or Phase, Angle of 63°.
Image scale is roughly 600 meters (1968 feet) per pixel".MareKromium
(4 voti)
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Propeller-PIA11672-a.jpgGiant "Propeller" in the A-Ring (CTX Frame)63 visiteAn unusually large "Propeller" feature is detected just beyond the Encke Gap in this Cassini image of Saturn’s outer A-Ring taken a couple days after the Planet’s August 2009 Equinox.
The unique geometry of Equinox has thrown into relief small moonlets within the Rings and the structures they create around them. Propeller-like features, a few kilometers long, centered on and created by the action of small embedded moonlets only about 100 meters across, were discovered early in the mission (see also PIA07792 and PIA07790).
These previous findings constituted the first recognition of the presence in Saturn’s Rings of bodies bigger than the largest ring particles (about 10 meters, or 30 feet, across) but smaller than the 8-Km-wide (about 5-mile-wide) ring moon, Daphnis, in the outer A-Ring.
From the 350-Km (about 220-mile) length of the shadow cast by this 130-Km-long (about 80-mile-long) Propeller, the heights of these features above the Ring-Plane have been measured to reach about 200 meters (650 feet), indicating the moonlet responsible for the Propeller in this image is likely to be 400 meters (1300 feet) across.
A previously released early-Equinox image also had revealed a moonlet in the outer B-Ring about 400 meters (1300 feet) across (see PIA11665).MareKromium
(4 voti)
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Propeller-PIA11672-b.jpgGiant "Propeller" in the A-Ring (EDM)57 visiteIt has since become a growing realization resulting from Cassini’s exploration of Saturn that the objects forming Saturn’s Rings very likely span the full spectrum of sizes, from the smallest dust-sized ring particles to the ring-moons like Daphnis and 29-Km-wide (18-mile-wide) Pan - a significant advance in divining the origin of Saturn’s Rings.
The novel illumination geometry that accompanies equinox lowers the Sun’s angle to the Ring-Plane, significantly darkens the Rings and causes out-of-plane structures to cast long shadows across the Rings. (The Rings have been brightened in this image to enhance visibility)
These scenes are possible only during the few months before and after Saturn’s Equinox which occurs only once in about 15 Earth years.
This view looks toward the Northern Side of the Rings from about 20° above the Ring-Plane.
The image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera on Aug. 13, 2009.
This view was acquired at a distance of approx. 1,2 MKM (about 746.000 miles) from Saturn and at a Sun-Saturn-Spacecraft, or Phase, Angle of 87°.
Image scale is roughly 7 Km (about 4,5 miles) per pixel.MareKromium
(4 voti)
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Rhea-PIA11550.jpgRhea (Natural Colors; credits: Lunexit)58 visiteCaption NASA:"The battered features of the moon Rhea, seen at low phase, appear washed out by the Sun.
This view looks toward the Saturn-facing side of Rhea at a Sun-Rhea-Spacecraft, or Phase, Angle of 15°. To see Rhea at an even lower phase angle -- near opposition -- see PIA10542.
North on Rhea is up and rotated 7° to the left.
The image was taken in Visible Light with the Cassini spacecraft narrow-angle camera on May 26, 2009. The view was obtained from a distance of approx. 1,4 MKM (such as about 870.000 miles) from Rhea.
Image scale is roughly 9 Km (approx. 5,5 miles) per pixel".MareKromium
(4 voti)
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Janus-PIA11575.jpgJanus (Natural Colors; credits: Lunexit)59 visiteCaption NASA:"The Cassini Spacecraft eyes a prominent crater on the moon Janus.
The South Pole lies on the Terminator at the bottom left of the image. This view is centered on terrain at 16° South Lat., 64° West Long.; this view looks toward the Leading Hemisphere of Janus (about 179 Km, or approx. 111 miles across). North on Janus is up and rotated 31° to the right.
The image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera on July 26, 2009. The view was acquired at a distance of approx. 98.000 Km (such as about 61.000 miles) from Janus and at a Sun-Janus-Spacecraft, or Phase, Angle of 58°.
Image scale is roughly 586 meters (1922 feet) per pixel".MareKromium
(4 voti)
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The_Rings-N00140429.jpgRings and "noise"58 visitenessun commentoMareKromium
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Tethys-N00126733.jpgCrescent Tethys (Natural Colors; credits: Lunexit)56 visiteN00126733.jpg was taken on December 17, 2008 and received on Earth December 17, 2008. The camera was pointing toward TETHYS that, at the time, was approximately 527.571 Km away. This image was taken using the CL1 and CL2 filters and it has not been validated or calibrated.MareKromium
(4 voti)
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Prometheus-PIA11553.jpgPrometheus, its Shadow and Streamer Channel59 visiteCaption NASA:"The moon Prometheus casts a shadow on the thin "F"-ing marked with Streamer-Channels created by the moon in this image taken as Saturn approaches its August 2009 Equinox.
The gravity of potato-shaped Prometheus (about 86 Km, or approx. 53 miles across) periodically creates Streamer-Channels in the "F"-Ring.
(For further examples and to learn more, see PIA10461 and PIA10593. If you want to watch a movie of this process, please refer to and see PIA08397).
The novel illumination geometry created as Saturn approaches its August 2009 Equinox allows moons orbiting in or near the plane of Saturn's Equatorial Rings to cast shadows onto the Rings. These scenes are possible only during the few months before and after Saturn's Equinox which occurs only once in about 15 Earth years.
To learn more about this special time and to see movies of moons' shadows moving across the Rings, see PIA11651 and PIA11660.
This view looks toward the unilluminated side of the Rings from about 52° above the Ring-Plane. The image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera on June 15, 2009.
The view was acquired at a distance of approx. 1,8 MKM (about 1,1 MMs) from Prometheus and at a Phase Angle of 85°.
Image scale is roughly 11 Km (a little less than 7 miles) per pixel".MareKromium
(4 voti)
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Mimas-PIA11540.jpgHighlighting Herschel Crater58 visiteCaption NASA:"The Herschel crater dominates this view of Saturn's moon Mimas. The about 130-Km, or approx. 80-mile, wide crater is located in the Middle Latitudes of Mimas.
The most brightly lit Terrain seen here - lit by the Sun - is on the Leading Hemisphere of the moon. Light reflected from Saturn dimly lights the other side of the moon.
This view is centered on terrain at 37° North Lat. and 300° West Long. The North Pole of Mimas lies on the Terminator, about a quarter of the way inward from the top of the image.
Scale in the original image was 10 Km (about 6 miles) per pixel. The image has been magnified by a factor of two and contrast-enhanced to aid visibility. The image was taken in Visible Light with the Cassini Spacecraft narrow-angle camera on June 3, 2009.
The view was obtained at a distance of approx. 1,7 MKM (about 1,1 MMs) from Mimas and at a Sun-Mimas-Spacecraft, or Phase, Angle of 119°".MareKromium
(4 voti)
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Dione-PIA11532.jpgWispy Dione58 visiteCaption NASA:"The Cassini Spacecraft looks toward the wispy, fractured terrain of the Trailing Hemisphere of the moon Dione.
To learn more about Dione's "Wisps", see also PIA08960.
Lit Terrain seen here is on the Trailing Hemisphere of Dione (about 1123 Km, or approx. 698 miles across). North on Dione is up and rotated 29° to the right.
The image was taken in visible light with the Cassini Spacecraft narrow-angle camera on May 26, 2009. The view was acquired at a distance of approx. 1,3 MKM (about 808.000 miles) from Dione and at a Sun-Dione-Spacecraft, or Phase, Angle of 35°.
Image scale is roughly 8 Km (about 5 miles) per pixel".MareKromium
(4 voti)
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Prometheus-PIA11531.jpgPrometheus59 visiteCaption NASA:"The moon Prometheus and a bit of Saturn's Northern Hemisphere are both brilliantly lit by the Sun here, making the A-Ring seem dim in comparison.
The bright limb of Saturn's Northern Hemisphere can be seen through the A-Ring in the lower left of the image.
Prometheus (about 86 Km, or approx. 53 miles across) orbits in the Roche Division between Saturn's A and F-Ring.
For a similar view of Pandora, another of the F-Ring's Shepherding Moons, see PIA09899.
This view looks toward the sunlit side of the Rings, from about 20° below the Ring-Plane.
The image was taken in Red Light with the Cassini Spacecraft narrow-angle camera on May 25, 2009. The view was acquired at a distance of approx. 694,000 Km (about 431.000 miles) from Prometheus and at a Sun-Prometheus-Spacecraft, or Phase, Angle of 49°.
Image scale is roughly 3,6 Km (about 2,2 miles) per pixel".MareKromium
(4 voti)
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