| Piú viste - Saturn: the "Ringed Beauty" and His Moons |
Saturn-PIA11667.jpgThe Lord of the Rings (Natural Colors; credits: NASA/JPL/Space Science Institute)59 visiteCaption NASA:"Of the countless Equinoxes Saturn has seen since the birth of the Solar System, this one, captured here in a mosaic of light and dark, is the first witnessed up close by an emissary from Earth … none other than our faithful robotic explorer, Cassini.
Seen from our planet, the view of Saturn’s Rings during Equinox is extremely foreshortened and limited. But in orbit around Saturn, Cassini had no such problems. From 20° above the Ring-Plane, Cassini’s wide angle camera shot 75 exposures in succession for this mosaic showing Saturn, its Rings, and a few of its moons a day and a half after exact Saturn Equinox, when the Sun’s disk was exactly overhead at the Planet’s Equator.
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 look anomalously bright and to cast shadows across the Rings themselves.
These scenes are possible only during the few months before and after Saturn’s Equinox which occurs only once in about 15 Earth years.
Before and after Equinox, Cassini’s cameras have spotted not only the predictable shadows of some of Saturn’s moons (see also PIA11657), but also the shadows of newly revealed vertical structures in the Rings (see, for example, PIA11665).
Also at Equinox, the shadows of the Planet’s expansive Rings are compressed into a single, narrow band cast onto the Planet as seen in this mosaic. (For an earlier view of the Rings’ wide shadows draped high on the Northern Hemisphere, see PIA09793)
The images comprising the mosaic, taken over about eight hours, were extensively processed before being joined together. First, each was re-projected into the same viewing geometry and then digitally processed to make the image “joints” seamless and to remove lens flares, radially extended bright artifacts resulting from light being scattered within the camera optics.
At this time so close to Equinox, illumination of the Rings by sunlight reflected off the planet vastly dominates any meager sunlight falling on the Rings. Hence, the half of the Rings on the left illuminated by planetshine is, before processing, much brighter than the half of the Rings on the right. On the right, it is only the vertically extended parts of the Rings that catch any substantial sunlight.
With no enhancement, the Rings would be essentially invisible in this mosaic. To improve their visibility, the dark (right) half of the Rings has been brightened relative to the brighter (left) half by a factor of three, and then the whole Ring System has been brightened by a factor of 20 relative to the Planet. So the dark half of the rings is 60 times brighter, and the bright half 20 times brighter, than they would have appeared if the entire System, Planet included, could have been captured in a single image.
The moon Janus (about 179 Km, or approx. 111 miles across) is on the lower left of this image. Epimetheus about (113 Km, or approx. 70 miles across) appears near the middle bottom. Pandora (about 81 Km, or approx. 50 miles across) orbits outside the Rings on the right of the image. The small moon Atlas (about 30 Km, or approx. 19 miles across) orbits inside the thin F-Ring on the right of the image.
The brightnesses of all the moons, relative to the Planet, have been enhanced between 30 and 60 times to make them more easily visible. Other bright specks are background stars. Spokes -- ghostly radial markings on the B ring -- are visible on the right of the image.
This view looks toward the northern side of the Rings from about 20° above the Ring-Plane.
The images were taken on Aug. 12, 2009, beginning about 1,25 days after exact equinox, using the red, green and blue spectral filters of the wide angle camera and were combined to create this Natural Colors view.
The images were obtained at a distance of approx. 847.000 Km (about 526.000 miles) from Saturn and at a Sun-Saturn-Spacecraft, or Phase, Angle of 74°.
Image scale is roughly 50 Km (about 31 miles) per pixel".
Nota Lunexit: una interpretazione in Colori Naturali davvero stupenda, per qualità, definizione e realismo. Una prova evidente che i lavori "brutti" (e cioè il 99% dei prodotti fotografici a colori riguardanti Marte) la NASA non li fa perchè "non è capace" (ovviamente), ma solo perchè "non vuole farli com sa fare".
Il motivo? Beh, certo non è "pigrizia" (anche se non si può mai dire)...MareKromium
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Tethys-PIA12319.jpgTethys and the Rings (Natural Colors; credits: NASA/JPL/Space Science Institute)59 visiteCaption NASA:"Cassini peers toward the distant, icy plains of Saturn's moon Tethys. The Planet's "A" and "F"-Rings slice across the top of this view.
This view of Tethys represents "Target 2" 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.
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. 1,4 MKM (about 900.000 miles) from Tethys".MareKromium
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Enceladus-N00143622-N00143643.gifFountains of Light and possible UFO (GIF-Movie; credits: Dr G. Barca)59 visiteDalla (sconfinata) Pazienza del nostro Grande Amico e Partner, Dr Gianluigi Barca, un GIF-Movie davvero bellissimo, affascinante ed intrigante.
Una scatola di cioccolatini (virtuali) al primo Lettore capace di identificare l'oggetto che sfreccia davanti alle telecamere di CASSINI mentre la "Palla di Neve" - Enceladus - continua ad eiettare ghiaccio nello Spazio circum-Saturniano!MareKromium
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Dione_Tethys-N00144184-N00144203-N00144746-N00144765.gifNight Passengers (GIF-Movie; credits: Dr G. Barca)59 visitenessun commentoMareKromium
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Saturn-PIA11640.jpgNarrow Shadow59 visiteCaption NASA:"From just above the Plane of Saturn's Rings, the Cassini Spacecraft snapped this shot of Saturn two months after Saturn's August 2009 Equinox, showing the shadow of its Rings as a narrow band on the Planet.
Cassini is looking toward the sunlit side of the rings from about 1° above the Ring-Plane.
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 look anomalously bright and cast shadows across 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.
Before and after Equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons (see, for instance, PIA11657), but also the shadows of newly revealed Vertical Structures in the Rings themselves (see PIA11665).
The image was taken with the Cassini Spacecraft wide-angle camera on Oct. 16, 2009 using a spectral filter sensitive to wavelengths of Near-InfraRed Light centered at 752 nanometers. The view was obtained at a distance of approx. 1,5 MKM (such as about 932.000 miles) from Saturn and at a Sun-Saturn-Spacecraft, or Phase, Angle of 83°.
Image scale is roughly 86 Km (approx. 53 miles) per pixel".MareKromium
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Rhea_and_Titan-EB.jpgJewels, in the Space of Saturn: Rhea and Titan (Natural Colors; credits: Elisabetta Bonora)59 visiteUn lavoro assolutamente PERFETTO e, detto sinceramente, di qualità mediamente superiore ai Lavori di colorizzazione "Made by NASA".
Complimenti vivissimi alla nostra Amica e Partner, Elisabetta Bonora!MareKromium
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Rhea_and_Titan-MF.jpgRhea and Titan (NIR View; credits: Dr M. Faccin)59 visite...Una "Visione" davvero splendida, da lasciare con il fiato sospeso...MareKromium
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The_Rings-PIA12512.jpgThe "E-Ring"59 visiteCaption NASA:"The Cassini Spacecraft takes a look at Saturn's diffuse E-Ring which is formed from icy material spewing out of the South Pole of the moon Enceladus (see PIA08921 to learn more about how Enceladus creates the E-Ring). The E-Ring is seen nearly edge-on from slightly above the Northern Side of Saturn's Ring-Plane.
The image was taken in Visible Light with the Cassini Spacecraft wide-angle camera on Oct. 23, 2009. The view was acquired at a distance of approx. 2,5 MKM (such as about 1,6 MMs) from Saturn.
Image scale is roughly 149 Km (approx. 92 miles) per pixel".MareKromium
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The_Rings-PIA12518.jpgWithin the Rings (Natural Colors; credits: NASA/JPL/Space Science Institute)59 visiteCaption NASA:"Saturn's moon Epimetheus casts a shadow across the colourful Rings of Saturn, in this image taken before the Planet's August 2009 Equinox.
Epimetheus (approx. 113 Km, or about 70 miles across) is visible as a small dot at the center of the bottom of the image.
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 look anomalously bright and cast shadows across 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. Before and after Equinox, Cassini's cameras have spotted not only the predictable shadows of some of Saturn's moons (see PIA11657), but also the shadows of newly revealed Vertical Structures in the Rings themselves (see PIA11665).
Images taken using red, green and blue spectral filters were combined to create this Natural Color view. This view looks toward the southern, sunlit side of the Rings from about 39° below the Ring-Plane.
The images were obtained with the Cassini Spacecraft wide-angle camera on June 8, 2009 at a distance of approx. 725.000 Km (about 450.000 miles) from Saturn.
Image scale is roughly 40 Km (about 25 miles) per pixel".MareKromium
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Saturn-PIA12533.jpgEternal Vision (Natural Colors; credits: NASA/JPL/Space Science Institute)59 visiteCaption NASA:"A pastel crescent of Saturn is interrupted by the moon Mimas and the Rings in this color image.
Mimas (approx. 396 Km - or about 246 miles across) appears as a dark speck just above the Rings.
This view looks toward the Northern, 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 obtained with the Cassini Spacecraft wide-angle camera on Oct. 27, 2009 at a distance of approx. 2,2 MKM (such as about 1,4 MMs) from Saturn.
Image scale is roughly 129 Km (approx. 80 miles) per pixel".MareKromium
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Tethys-Mimas-EB.jpgSaturnian Twins: Tethys and Mimas (Natural Colors - Image-Mosaic; credits: Elisabetta Bonora - Lunexit Team)59 visitenessun commentoMareKromium
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Saturn-EB.jpgMethane in the Clouds of Saturn (Special Image Processing - credits: Elisabetta Bonora - Lunexit Team)59 visitenessun commentoMareKromium
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