Jupiter: the "King" and His Moons
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PSP_002162_9030_RED_browse.jpgJupiter from Mars53 visiteCaption NASA:"The HiRISE camera is the most powerful telescope to have left Earth orbit. As such, it is capable of some interesting astronomical observations.
This image of Jupiter and its major satellites was acquired to calibrate the pointing and color response of the camera. An oversight in planning this unusual observation put the focus mechanism in the wrong location, blurring the image. This does not detract from the calibration objectives, but makes the raw image less esthetic.
To compensate, the image has been "sharpened" on the ground by Dennis Gallagher, the HiRISE chief optical designer. With this sharpening, and because Mars is closer to Jupiter than Earth is, this image has comparable resolution as the HST's pictures of Jupiter.
The colors are not what is seen by the human eye because HiRISE is able to detect light with a slightly longer wavelength than we can (that is, the infrared)".MareKromium
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The Galileans~0.jpgThe "Galileans"53 visiteIo, the large volcanic satellite of Jupiter, was first shown to the World in images transmitted from the Voyager 1 Spacecraft.
Unfortunately their cameras had no red filters and color pictures often had to be extrapolated substituting orange for red and violet for blue.
In the case of Io, this led to a garish 'pizza' appearance with many reproductions of the released images further wandering toward the red until Io looked like tomato soup!
Io is very bright, and largely a pale yellow with gray green to orange regions. Galileo has greatly refined the color information from Io. The albedo of Io (il primo a Sx) is a bright 0,6, while Europa (the brightest) is 0,64. Ganymede's albedo is just 0,42 and then - last - the dark Callisto is only 0,2.
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Thebe-Amalthea-Metis-PIA02531.jpgThebe, Amalthea and Metis53 visiteUna curiosità: è difficile non notare la notevole somiglianza fra Thebe (il primo "macigno" da Sx) e la Luna Marziana Phobos.
E qual'è il "punto di contatto" fra questi due corpi celesti?
Ma si tratta, naturalmente, del grande cratere che, nel caso di Thebe, notiamo sulla Sx del piccolo Satellite. Un grande cratere che ci ricorda molto da vicino lo "Stickney Crater" di Phobos.
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Thebe-PIA01075.jpgThebe53 visiteOriginal caption:"These 2 images of the Jovian moon Thebe were taken by Galileo's solid state imaging system in November 1996 and June 1997, respectively. North is approximately up in both cases. Thebe, whose longest dimension is about 116 Km (or 72 miles) across, is tidally locked so that the same side of the satellite always points towards Jupiter, similar to how the nearside of our own Moon always points toward Earth. In such a tidally locked state, one side of Thebe always points in the direction in which Thebe moves as it orbits about Jupiter. This is called the "leading side" of the moon and is shown at the left. The image on the right emphasizes the side of Thebe that faces away from Jupiter (the so-called "anti-Jupiter" side). Note that there appear to be at least three or four very large impact craters on the satellite - very large in the sense that each of these craters is roughly comparable in size to the radius of Thebe".
Nota: crateri troppo grandi per un mondo così piccolo...
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ZA-The Red Spot from HST.jpgMoments of the "Red Spot" - HST60 visitenessun commento
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ZC-Jupiter from Mars-PIA04532_modest.jpgJupiter and 3 Galilean Moons from Mars78 visiteCi siamo chiesti tante volte, guardando Giove dalla Terra, come lo si vedrebbe da Marte. Ebbene, abbiamo trovato la risposta (grazie all'aiuto del Mars Global Surveyor Orbiter): in questo frame davvero eccezionale, Giove e 3 dei suoi 4 Satelliti Galileiani, così come li vedremmo da Marte! Un'immagine bellissima da guardare e su cui occorre riflettere molto. Perchè? Perchè conquistare lo Spazio, alle volte, vuol dire anche ampliare i confini dell'Immaginazione...
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