| Risultati della ricerca nelle immagini - "Oberon" |
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)69 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 260 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...59 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"65 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)55 visitenessun commento
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Oberon-vg2_2683625.jpgLeaving Oberon (HR)55 visitenessun commento
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Uranus-familyportrait-PIA01975_modest.jpgThe 5 major moons of Uranus63 visiteThis "family portrait" of Uranus' 5 largest moons was compiled from images sent back Jan. 20, 1986, by Voyager 2 spacecraft. The pictures were taken through a clear filter from distances of 5 to 6,1 MKM (3,1 to 3.8 MMs). In this comparison, we see the relative sizes and relativities of the satellites. From left, in order of increasing distance from the planet, they are Miranda, Ariel, Umbriel, Titania and Oberon. The 2 largest, Oberon and Titania, are about half the size of Earth's Moon, or roughly, 1.600 Km (1.000 miles) in diameter. Miranda, smallest of the 5, has about one-quarter to one-third the diameter. Even in these distant views, the satellites exhibit distinct differences in appearance. On average, Oberon and Titania reflect about 20% of the sunlight, Umbriel about 12%, Ariel and Miranda about 30%. Ariel shows the largest contrast on its surface, with the brightest areas about 25%. All five satellites show only slight color variations on their surfaces, with their average color being very nearly gray. The best views of the satellites will be obtained Jan. 24, the day of closest approach.
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