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OBERON.jpgOberon from Voyager 292 visiteA parte i consueti segni (crateri) lasciati da un innumerevole quantitativo di impatti, risulta abbastanza agevole notare l'esistenza di "mari" simili a quelli della nostra Luna. Si tratta di ampie distese, relativamente lisce, che si estendono per circa un quarto della superficie totale del Satellite. Da osservare, inoltre, la protuberanza semiconica che appare sul bordo del Satellite, alla Sn dell'Osservatore, a ore 8 (un rilievo alto circa 6 Km).
Si tratta di una montagna o di un antico vulcano?
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Oberon-PIA01352-PCF-LXTT-IPF.jpgIcy Oberon (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunar Explorer Italia/Italian Planetary Foundation)58 visiteUranus' outermost and largest moon, Oberon, can be very well seen in this NASA - Voyager 2 frame which was obtained January, 22, 1986, from a distance of approx. 2,77 Million KiloMeters (such as a little more than 1,72 Million Miles). The Clear-Filter Image, shuttered by the Voyager's Narrow-Angle Camera, shows us that Oberon displays several distinct Highly Reflective (---> High-Albedo) "Patches" of its Surface which also show - and this circumstance still sounds kind of strange/unusual - very Low-Albedo Centers. Some of the bright Patches are suggestive of Radial Patterns that could represent the visible consequence of powerful Impact Events which occurred on a basically Ice-rich Surface (in other words, we may be looking at Rayed Impact Craters that formed - were excavated - on an extremely hard and frozen Surface) .
On average, Oberon reflects (in all directions) only about 20% (twenty-percent) of the Incident Sunlight and that fact makes it Celestial Body with a (relatively) Low Albedo. The moon is about 1600 Km (such as approx. 993,6 miles) in diameter; the resolution of this image is roughly 51 Km (such as about 31,67 miles) per pixel. This frame was taken 2 (two) days before Voyager's 2 Closest Approach to Oberon (at which point the Spacecraft flew-by Oberon at a distance of approx. 471.000 Km - such as about 292.491 miles - from its frozen Surface).
This frame (which is an Original NASA - Voyager 2 Spacecraft Natural Color image published on the NASA - Planetary Photojournal with the ID n. PIA 01352) has been additionally processed, contrast enhanced, magnified to aid visibility of the Surface details and then re-colorized, according to an educated guess carried out by Dr Paolo C. Fienga/LXTT/IPF, in what they should be its Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Voyager 2 Spacecraft and then looked outside, towards the Uranian moon Oberon), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Oberon, each having a different Albedo (---> Reflectivity) and Chemical Composition.
Note 1: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of Oberon - as it is in this frame - would appear, to an average human eye, a little bit lower than it has been shown (or, better yet: interpreted) here.
Note 2: the "squared" feature visible at about 4 o'clock of Oberon's disk (almost on the Limb of the moon and right on the Terminator Line), is just an original image defect.MareKromium
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Oberon-V2-PIA00034_modest.jpgOberon, from 660.000 Km - Voyager 256 visiteCaption NASA originale:"This Voyager 2 picture of Oberon is the best the spacecraft acquired of Uranus' outermost moon. The picture was taken shortly after 3:30 a.m. PST on Jan. 24, 1986, from a distance of 660.000 Km. The color was reconstructed from images taken through the narrow-angle camera's violet, clear and green filters. The picture shows features as small as 12 Km on the moon's surface. Clearly visible are several large impact craters in Oberon's icy surface surrounded by bright rays similar to those seen on Jupiter's moon Callisto. Quite prominent near the center of Oberon's disk is a large crater with a bright central peak and a floor partially covered with very dark material. This may be icy, carbon-rich material erupted onto the crater floor sometime after the crater formed. Another striking topographic feature is a large mountain (vedi il frame "Oberon's Peak"), about 6 km high, peeking out on the lower left limb".
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Oberon-V2-PIA01352_modest.jpgOberon, from far away...53 visiteOberon, la Luna Maggiore di Urano: la più esterna e la più grande.
In questa immagine (a differenza della precedente che, ad oggi, è la migliore disponibile!) la Sonda Voyager 2 era ancora troppo lontana da Oberon per catturarne i segreti (la fotografia è stata scattata da una distanza di circa 2.700.000 Km!), ma alcuni dettagli delle sua superficie (i quali peraltro evidenziano una scarsissima albedo: Oberon, in effetti, riflette - in media - circa il 20% della luce solare che riceve) appaiono già con una certa chiarezza.
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Oberon-vg2_2683623-1.jpgOberon's "Peak"62 visiteEd ecco il più intrigante rilievo superficiale di Oberon: una montagna (la cui forma, per gli appassionati di "Space Oddities", ricorda una specie di piramide) di circa 6000 mt di altezza che spicca, molto chiaramente, sul bordo di questa affascinante e lontano Corpo Celeste.
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Oberon-vg2_2683623.jpgLeaving Oberon (HR)53 visitenessun commento
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Oberon-vg2_2683625.jpgLeaving Oberon (HR)53 visitenessun commento
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TITANIA.jpgTitania from Voyager 2 (1)92 visiteQualche immagini di Titania.
Questo Satellite di Urano assomiglia decisamente ad Oberon e le sue caratteristiche superficiali lo rendono anche molto simile alla nostra Luna.
In questa immagine appare piuttosto chiaramente, verso il basso ed esattamente sulla linea del terminatore, un profondo canale (crepaccio?). Reminiscenze di antiche eruzioni ed eventi sismici collegati o è forse il segno dell'impatto con un altro corpo celeste che si è abbattuto su Titania con un angolo di incidenza estremamente basso? Onestamente non lo sappiamo. Gli Studiosi di Scienze Planetarie e gli Esperti di geologia potrebbero esserci di aiuto al riguardo. Noi abbiamo scambiato qualche parola con uno di questi e ci è stato detto che le "scalfitture" visibili sulla superficie di Titania dovrebbero essere il risultato di violentissimi cataclismi i quali hanno, in un certo senso, fratturato la crosta del Satellite.
Ma relativamente all'origine (interna od esterna?) di questi eventi la risposta, ovviamente, non può essere data.
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Titania from Voyager 2.jpgTitania from Voyager 2 (2)77 visitenessun commento
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Titania-PIA01978-PCF-LXTT-IPF.jpgOn the Limb of Titania (Possible Absolute Natural Colors; credits for the additional process. and color. Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)80 visiteLike their semi-divine namesakes, Dione's twin Impact Craters Romulus and Remus (just above-right of the center) stand together while Dido, the larger Impact Crater showing a magnificent and impressive Central Peak, lies to the South/East, on the lower left Limb of Dione and almost half-way on top of the Terminator. The lit Terrain seen here is on the Saturn-facing Hemisphere of Dione and North is up.
The image was taken in Visible Light with the NASA - Cassini Spacecraft Narrow-Angle Camera on April 28, 2013. The view was obtained at a distance of approximately 870.000 miles (such as a little more than 1,4 Million KiloMeters) from Dione and at a Sun-Dione-Cassini Spacecraft, or Phase, Angle of 77°. Image scale is roughly 5 miles (a little more than 8 Km) per pixel.
This frame (which is an Original NASA - Cassini Spacecraft b/w frame published on the NASA - Planetary Photojournal with the ID n. PIA 17126) has been additionally processed, contrast enhanced, magnified to aid visibility of the Surface details and then colorized, according to an educated guess carried out by Dr Paolo C. Fienga/LXTT/IPF, in what they should be its Absolute Natural Colors (such as the colors that a human eye would actually perceive if someone were onboard the NASA - Cassini Spacecraft and then looked outside, towards the Saturnian moon Dione), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team. Different colors, as well as different shades of the same color, mean, among others, the existence of different Elements present on the Surface of Dione, each having a different Albedo (---> Reflectivity) and Chemical Composition.
Note: it is possible (but we, as IPF, have no way to be one-hundred-percent sure of such a circumstance), that the actual luminosity of Dione - as it is in this frame - would appear, to an average human eye, a little bit lower than it has been shown (or, better yet: interpreted) here.MareKromium
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Titania-PIA01979-PCF-LXTT-IPF.jpgTitania (Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga/Lunar Explorer Italia/Italian Planetary Foundation)98 visiteCaption NASA:"Voyager 2 obtained this full-disk view of Uranus' moon Titania in the early morning hours of Jan. 24, 1986, from a distance of about 500.000 Km (approx. 300.000 miles). Many circular depressions -- probably impact craters -- are visible in this clear-filter image returned by the Voyager narrow-angle camera.
Other bright spots are distinguished by radiating rays and are probably halo craters that mark relatively more recent impacts. Even more interesting are Linear Troughs (right) that are probably Fault Canyons (Tectonic Fractures). The Troughs break the crust in two directions, an indication of some tectonic extension of Titania's crust. These features indicate that this icy satellite has a dynamic, active interior. Titania is about 1600 Km (approx. 1000 mi) in diameter; the resolution of this image is about 9 Km (approx. 6 mi) per pixel". MareKromium
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Titania-PIA01979.jpgTitania (possible Natural Colors; credits: Lunar Explorer Italia)53 visiteCaption NASA:"Voyager 2 obtained this full-disk view of Uranus' moon Titania in the early morning hours of Jan. 24, 1986, from a distance of about 500.000 Km (approx. 300.000 miles). Many circular depressions -- probably impact craters -- are visible in this clear-filter image returned by the Voyager narrow-angle camera.
Other bright spots are distinguished by radiating rays and are probably halo craters that mark relatively more recent impacts. Even more interesting are Linear Troughs (right) that are probably Fault Canyons (Tectonic Fractures). The Troughs break the crust in two directions, an indication of some tectonic extension of Titania's crust.
These features indicate that this icy satellite has a dynamic, active interior. Titania is about 1600 Km (approx. 1000 mi) in diameter; the resolution of this image is about 9 Km (approx. 6 mi) per pixel". MareKromium
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