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Saturn-PIA21899.gifPolar Lights (Auroral Emissions from the North Pole of Saturn)123 visiteCaption NASA Originale:"On Sept. 14, 2017, one day before making its final plunge into Saturn's Atmosphere, NASA's Cassini Spacecraft used its Ultraviolet Imaging Spectrograph, or UVIS, instrument to capture this final view of Ultraviolet Auroral Emissions over the Planet's North Polar Regions.
The view is centered on the North Pole of Saturn, with lines of Latitude visible for 80, 70 and 60°. Lines of Longitude are spaced 40° apart. The Planet's Day-Side is at the bottom of the picture, while the Night-Side is at the top. A sequence of images from this observation has also been assembled into a movie sequence. The last image in the movie was taken about an hour before the still image, which was the actual final UVIS auroral image.
Auroral Emissions are generated by charged particles traveling along the invisible lines of Saturn's Magnetic Field. These particles (then) precipitate into the Atmosphere, releasing light when they strike (the) Gas Molecules (that are present) there.
Several individual auroral structures are visible here, despite that this UVIS view was acquired at a fairly large distance from the Planet (such as about 424.000 miles or approx. 682.361,856 Km). Each of these features is connected to a particular phenomenon (occurring) in the Saturnian Magnetosphere. For instance, it is possible to identify Auroral "signatures" here that are related to the injection of "Hot Plasma" from the Day-Side Magnetosphere, as well as Auroral Features associated with a change in the Magnetic Field's shape (existing) on the Magnetosphere's Night-Side.
Several possible scenarios have been postulated over the years to explain Saturn's changing Auroral Emissions, but researchers are still far from a complete understanding of this complicated puzzle. Researchers will continue to analyze the hundreds of image sequences UVIS obtained of Saturn's auroras during Cassini's 13-year mission, with many new discoveries likely to be made.
This image and movie sequence were produced by the Laboratory for Planetary and Atmospheric Physics (LPAP) of the STAR Institute of the University of Liege in Belgium, in collaboration with the UVIS Team".MareKromiumMar 12, 2020
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Titan-PIA21902.jpgThe uneven Atmosphere of Titan146 visiteLe diverse stratificazioni dell'Alta Atmosfera di Titano sono ben visibili in questa foto CASSINI dell'ormai lontano AD 2005.
In questo frame, ci appare del tutto evidente che la densitą dell'Atmosfera di Titano NON é strettamente correlata all'altezza della stessa (ergo delle sue nuvole e nebbie) rispetto al Datum (Altitudine Zero); le turbolenze (e quindi anche la composizione chimica dell'Atmosfera) sembrano estendersi e rivolgersi, a volte, da strati pił bassi verso quelli pił alti, mentre, in altri casi, sembra avvienire esattamente l'opposto.
Questa conclusione é stata basata sull'esame di immagini sequenziali che coprissero la medesima Regione Titaniana per svariati minuti (o decine di minuti). In questo frame le innumerevoli "disomogeneitą" sono del tutto palesi.
Non possiamo neppure escludere l'esistenza di (violentissime) correnti convettive le cui cause, tuttavia, non sono ancora chiare.
Caption NASA Originale:"In this view, individual Layers of Haze can be distinguished in the Upper Atmosphere of Titan, Saturn's largest moon. Titan's Atmosphere features a rich and complex chemistry originating from Methane and Nitrogen (---> Azoto) and evolving into complex molecules, eventually forming the "Smog! that surrounds the moon (even at extremely lower altitudes).
This Natural Color image was taken in Visible Light with the Cassini Spacecraft wide-angle camera on March 31, 2005, at a distance of approximately 20.556 miles (such as about 33.081,67 Km) from Titan. The view looks toward the North Polar Regions on the moon's Night-Side. Part of Titan's sunlit crescent is visible at right (Dx).
The Cassini Spacecraft ended its mission on Sept. 15, 2017".MareKromiumMar 12, 2020
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016-1-Ceres-Occator-Black_Shadow-01.jpgDark "Spot" inside Occator Crater (CTX Frame)127 visiteMareKromiumFeb 09, 2020
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017-1-Ceres-Occator-Black_Shadow-02.jpgDark "Spot" inside Occator Crater (EDM)157 visiteMareKromiumFeb 09, 2020
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018-1-Ceres-PIA22764.jpgOccator Crater on the Limb...144 visitenessun commentoMareKromiumFeb 09, 2020
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020-1-Ceres-PIA22641.jpgUnusually-looking Surface Feature on 1-Ceres129 visiteCaption NASA Originale:"This image was obtained by NASA's Dawn Spacecraft on July 17, 2018 from an altitude of about 25 miles (such as approx. 40,23 Km).
The center of this picture is located at about 31,0° South Latitude and 248,9° East Longitude".MareKromiumFeb 09, 2020
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021-1-Ceres-Cerealia_Facula-Occator_Crater-PIA21924.jpgCerealia Facula120 visiteCaption NASA Originale"This mosaic of Cerealia Facula is based on images obtained by NASA's Dawn Spacecraft in its second extended mission, from an altitude as low as about 21 miles (such as approx. 33,79 Km). The contrast in resolution obtained by the two phases is visible here, reflected by a few gaps in the high-resolution coverage. This image is superposed to a similar scene acquired in the low-altitude mapping orbit of the mission from an altitude of about 240 miles (i.e. approx. 386,24 km).
The increased resolution afforded by the low altitude is revealing intimate details about the relationships between bright and dark materials across the Facula (---> Bright Spot), which will help resolve the mystery of its origin.
Cerealia Facula is located at about 19,7° North Latitude and 239,6° East Longitude".MareKromiumFeb 09, 2020
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011-1-Ceres-Full_Rotation.gif1-Ceres: Full Rotation (GIF-Movie - Credits: NASA/JPL)125 visitenessun commentoMareKromiumFeb 09, 2020
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Titan-PIA22481-1.jpgThe Great Seas and Lakes of Titan181 visiteCaption NASA:"During NASA's Cassini mission's final distant encounter with Saturn's giant moon Titan, the Spacecraft captured this view of the truly enigmatic moon's North Polar landscape of Lakes and Seas, which are filled with liquid Methane and Ethane.
Punga Mare (about 240 miles, or approx. 386,2 Km, across) is seen just above the center of the mosaic, with Ligeia Mare (roughly 300 miles, or about 48,3 Km, wide) below center and vast Kraken Mare stretching off 730 miles (such as approx. 1.174,8 Km) to the left of the mosaic. Titan's numerous smaller and still Unnamed Lakes can be seen around the seas and scattered around the right side of the mosaic. Among the ongoing mysteries about Titan is how these Seas and Lakes are formed.
Another mystery at Titan has been the weather. With its extremely dense Atmosphere, Titan has a Methane Cycle much like Earth's Water Cycle of evaporation, cloud formation, rainfall, surface runoff into Rivers, and collection in Lakes and Seas.
During Titan's Southern Summer, the Cassini Spacecraft also observed Cloud activity over the South Pole.
However, typical of observations taken during Northern Spring and Summer, the view here reveals only a few small clouds. They appear as bright features just below the center of the mosaic, including a few above Ligeia Mare.
The images in this mosaic were taken with the ISS Narrow-Angle Camera, using a spectral filter sensitive to wavelengths of Near-InfraRed Light centered at 938 nanometers.
They were captured on Sept. 11, 2017, during Cassini's last encounter with Titan. Four days later, Cassini was deliberately plunged into the Atmosphere of Saturn.
The view was obtained at a distance of approximately 87.000 miles (a little less than 140,013 Km) from Titan. Image scale is about 0,5 miles (approx. 800 meters) per pixel.
The image is an Orthographic Projection centered on 67,19° North Latitude and 212,67° West Longitude.
Note: an Orthographic View is most like the view seen by a distant observer looking through a telescope".MareKromiumGen 23, 2020
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Atlas,_Daphins_and_Pan-PIA21449.jpgAtlas, Daphnis and Pan166 visiteCaption NASA:"This montage of views from NASA's Cassini Spacecraft shows three of Saturn's Small Ring moons: Atlas, Daphnis and Pan at the same scale for ease of comparison.
Two differences between Atlas and Pan are obvious in this montage. Pan's Equatorial Band is much thinner and more sharply defined, and the central mass of Atlas (the part underneath the smooth Equatorial Band) appears to be smaller than that of Pan.
All of these images were taken using the Cassini Spacecraft Narrow-Angle Camera. The images of Atlas were acquired on April 12, 2017, at a distance of about 10.000 miles (approx. 16,0093 Km) and at a Sun-moons-Spacecraft angle (or Phase Angle) of 37°. All three images are oriented so that North is up".MareKromiumGen 23, 2020
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Saturn-PIA21895.jpgFarewell Cassini...167 visiteCaption NASA:"This Natural Color view view is the last image taken by the imaging cameras on NASA's Cassini Spacecraft. It looks toward the planet's night side, lit by reflected light from the Rings, and shows the location at which the Spacecraft would enter the Planet's Atmosphere a few hours later.
ThE view was created by using images taken with red, green and blue spectral filters. The imaging cameras obtained the view at approximately the same time that Cassini's Vsual and InfraRed Mapping Spectrometer made its own observations of the impact area in the thermal infrared.
This location - the site of Cassini's atmospheric entry - was at this time on the night side of the Planet, but would rotate into daylight by the time Cassini made its final dive into Saturn's Upper Atmosphere, ending its remarkable 13-year exploration of Saturn.
The view was acquired on Sept. 14, 2017 at 19:59 UTC (spacecraft event time). The view was taken in Visible Light using the Cassini Spacecraft Wide-Angle Camera at a distance of about 394.000 miles (such as roughly 634.081 Km) from Saturn. Image scale is about 11 miles (about 17,7 Km). The original image has a size of 512 x 512 pixels".MareKromiumGen 23, 2020
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Titan-PIA21624.jpgDouble Titan145 visiteCaption NASA:"These two views of Saturn's moon Titan exemplify how NASA's Cassini Spacecraft has revealed the Surface of this fascinating world.
Cassini carried several instruments to pierce the veil of hydrocarbon haze that enshrouds Titan. These include the Spacecraft's Radar and the Visual and InfraRed Mapping Spectrometer, or VIMS. The mission's imaging cameras also have several spectral filters sensitive to specific wavelengths of InfraRed Light that are able to make it through the Haze to the Surface and back into space. These "spectral windows" have enable the imaging cameras to map nearly the entire surface of Titan.
In addition to Titan's Surface, images from both the imaging cameras and VIMS have provided windows into the moon's ever-changing Atmosphere, chronicling the appearance and movement of Hazes and Clouds over the years. A large, bright and feathery band of Summer Clouds can be seen arcing across high Northern Latitudes in the view at right (Dx).
These views were obtained with the Cassini Spacecraft Narrow-Angle Camera on March 21, 2017. Images taken using red, green and blue spectral filters were combined to create the Natural-Color View on the left (Sx).
The false-color view at right (Dx) was made by substituting an InfraRed image (centered at 938 nanometers) for the red color channel.
The views were acquired at a distance of approx. 613.000 miles (such as a little more than 986.000 Km) from Titan and the Image Scale is roughly 4 miles (such as approx. 6,437 Km) per pixel".MareKromiumGen 23, 2020
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