| Ultimi arrivi - Neptune and His Moons |
Neptune and Triton - PIA01491_modest.jpgNeptune and Triton65 visiteCaption NASA originale:"This image was returned by the Voyager 2 spacecraft on July 3, 1989, when it was 76 MKM from Neptune. The planet and its largest satellite, Triton, are captured in the field of view of Voyager's narrow-angle camera through violet, clear and orange filters. Triton appears in the lower right corner at about 5 o'clock relative to Neptune.
Recent measurements from Voyager images show Triton to be between 1.400 and 1.800 Km in radius with a surface that is about as bright as freshly fallen snow". Set 22, 2004
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ZA-Triton-PIA02247_modest.jpgFarewell Triton...65 visiteCaption NASA originale:"Voyager 2 obtained this parting shot of Triton, Neptune's largest satellite, shortly after closest approach to the moon and passage through its shadow on the morning of Aug. 25, 1989. The distance to Triton was 90.000 Km and the phase angle was 155°, so that only a thin crescent of Triton's south polar region can be seen. Because of the high phase angle, and perhaps because of scattering sunlight in Triton's hazy atmosphere, few surface features are also easily discernible". Un piccolo commento: non sembra anche a Voi di intuire una sottile somiglianza fra Tritone e Titano?...Set 12, 2004
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Neptune-South_Hem-V2-PIA00050_modest.jpgThe Southern Polar Region of Neptune from approx. 4.200.000 Km71 visiteGli Scienziati, analizzando le immagini fornite dalla Sonda Voyager 2, si sono convinti che il sistema atmosferico di Nettuno sia molto simile a quello di Giove: queste grandi formazioni nuvolose bianche riprese dalle fotocamere della Sonda si formano, al pari dei venti che le sospingono, nelle zone equatoriali del Pianeta. Poi, spostandosi verso Sud, questi venti diventano sempre pił veloci e violenti. Un sistema configurato in maniera interessante ma, probabilmente, piuttosto instabile.Set 01, 2004
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Neptune-PIA01539_modest.jpgFarewell Neptune: a "bright smile" for the Earthlings...76 visiteCaption NASA originale:"Voyager 2's post-encounter view of Neptune's South Pole as the spacecraft sped away on a southward trajectory".
E con la Sonda Voyager 2 che sfiorava Nettuno e poi si dirigeva verso i pił estremi confini del Sistema Solare - perdendosi per sempre nello spazio interstellare - quest'ultimo frame ci mostra (passateci il termine) il "sorriso" di Nettuno per noi Terrestri.
Un "luminoso sorriso" che a noi piace pensare sia il suo modo di dire "Arrivederci"...Ago 26, 2004
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ZC-Neptune_s Rings-PIA01493_modest.jpgThe Rings of Neptune66 visiteCaption NASA originale:"In Neptune's outermost ring, 39.000 miles out, material mysteriously clumps into 3 arcs.
Voyager 2 acquired this image as it encountered Neptune in August 1989".Ago 26, 2004
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ZB-Neptune_s Partial Rings-PIA02200_modest.jpgNeptune's "Partial Rings" (or "Ring Arcs")76 visiteCaption NASA originale:"One of two new ring arcs, or partial rings, discovered by NASA's Voyager 2 spacecraft, is faintly visible here just outside the orbit of the Neptunian moon 1989N4, also discovered by Voyager 2.
The 155 second exposure taken by Voyager's narrow-angle camera shows the glare of an overexposed Neptune to the right of the moon and ring arc.
The two bright streaks below the moon and ring arc are stars.
The ring arc is approximately 50.000 Km (or 30.000 miles) long".Ago 26, 2004
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ZA-Neptune_s Rings-PIA01996_modest.jpgThe Rings of Neptune (closest approach)65 visiteCaption NASA originale:"The Voyager 2 spacecraft took this picture after closest approach to Neptune on Aug. 25 1989, using the clear filter of the wide-angle camera with an exposure time of 255 seconds. The view back towards Neptune at a phase angle of 135° found the 2 known rings to be 5 to 10 times brighter than seen in backscattering during Voyager approach at much lower phase angle. This brightness increase implies a large percentage of microscopic particles within the rings". Ago 26, 2004
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ZA-Neptune_s Rings-PIA01997_modest.jpgThe Rings of Neptune (full system) 170 visiteCaption NASA originale:"These two 591-second exposures of the rings of Neptune were taken with the clear filter by the Voyager 2 wide-angle camera on Aug. 26, 1989 from a distance of 280.000 Km (175.000 miles). The 2 main rings are clearly visible and appear complete over the region imaged. The time between exposures was 1 hour and 27 minutes. [During this period the bright ring arcs in the outer bright ring were not visible in either picture (they were unfortunately on the opposite side of the planet for each exposure).] Also visible in this image is the inner faint ring at about 42.000 km (25.000 miles) from the center of Neptune and the faint band which extends smoothly from the 53.000 Km (33.000 miles) ring to roughly halfway between the 2 bright rings". Ago 26, 2004
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ZA-Neptune_s Rings-PIA02202_modest.jpgThe Rings of Neptune (full system) 263 visiteCaption NASA originale:"This pair of Voyager 2 images (FDS 11446.21 and 11448.10), two 591-s exposures obtained through the clear filter of the wide angle camera, show the full ring system with the highest sensitivity. Visible in this figure are the bright, narrow N53 and N63 rings, the diffuse N42 ring, and (faintly) the plateau outside of the N53 ring (with its slight brightening near 57.500 Km)". Ago 26, 2004
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Triton-PIA02214_modest.jpgTriton from Voyager 2 (false colors)88 visiteCaption NASA originale:"This false color image of Triton is a composite of images taken through the violet, green and ultraviolet filters. The image was taken early on Aug. 25, 1989 when Voyager 2 was about 190.000 Km (118.000 miles) from Triton's surface. The smallest visible features are about 4 Km(2,5 miles) across. The image shows a geologic boundary between completely dark materials and patchy light/dark materials. A layer of pinkish material stretches across the center of the image. The pinkish layer must be thin because underlying albedo patterns show through. Several features appear to be affected by the thin atmosphere; the elongated dark streaks may represent particulate materials blown in the same direction by prevailing winds and the white material may be frost deposits". Ago 26, 2004
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Triton-PIA02213_modest.jpgThe limb of Triton (natural colors - elab. NASA)62 visiteCaption NASA originale:"This natural color image of the limb of Triton was taken early in the morning of Aug. 25, 1989, when the Voyager 2 spacecraft was at a distance of about 210.000 Km (128.000 miles) from the icy satellite. The largest surface features visible area about 3 miles across. The picture is a composite of images taken through the violet, green and clear filters.
The image shows a geologic boundary between a rough, pitted surface to the right and a smoother surface to the left". Ago 26, 2004
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Neptune-PIA02245.jpgNeptune from 16.000.000 Km59 visiteCaption NASA originale:"This color image, produced from a distance of about 16 MKM, shows several complex and puzzling atmospheric features. The Great Dark Spot (GDS) seen at the center is about 13.000 Km by 6.600 km in size - as large along its longer dimension as the Earth. The bright, wispy "cirrus-type" clouds seen hovering in the vicinity of the GDS are higher in altitude than the dark material of unknown origin which defines its boundaries". Ago 26, 2004
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