| Ultimi arrivi - Titan: The "Foggy" Moon |
Titan-PIA08126.jpgShining through the Rings...54 visiteCaption originale:"Titan's smoggy atmosphere glows brilliantly in scattered Sunlight, creating a thin, gleaming crescent beyond Saturn's Rings. At this slight angle above the Ring-Plane, the thin F-Ring shines brightly. Light from Titan's eastern and western limbs (edges) penetrates the Cassini Division, which looks like a thin gap from this angle.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 18, 2006, at a distance of approx. 1 MKM (such as about 600.000 miles) from Saturn. Planet-sized Titan (5.150 Km, or 3,200 miles across) was 2,2 MKM (about 1,4 MMs) from Cassini at that time. The image scale is 13 Km (8 miles) per pixel on Titan".
Nota: crediamo che sia la prima volta in cui la NASA, nel fornire i dati contingenti sul frame (ivi, in particolare, la distanza Sonda-Oggetto Ripreso), aggiunge la precisazione "...at that time...".
Ci teniamo a sottolineare che questo tipo di precisazione (a nostro parere fondamentale per far capire a tutti i Lettori - e soprattutto ai più giovani - che la "staticità" non appartiene al Cosmo) l'abbiamo introdotta noi, come Lun-Ex-It, in sede di integrazione dei dettati (captions) originali dei frames relativi a Saturno ed al suo Sistema.Mar 03, 2006
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Titan-W00013654-1.jpgA "bright light" in the clouds? (LR)55 visiteSi tratta dello stesso frame che evidenzia una possibile Anomalìa negli strati alti dell'atmosfera di Titano, ma con una risoluzione leggermente più bassa (500x500 anzichè 512x512). L'abbassamento di risoluzione, come potete verificare Voi stessi, non ha danneggiato la percezione del flash bianco, anzi: diremmo che in questo frame (sempre NASA Originale: non siamo stati noi a ridurne la risoluzione) la possibile Anomalìa trova un modo migliore per evidenziarsi.
Nostra opinione: premesso che si tratta di una sensazione, ottenuta su besi meramente intuitive e non sostanziabili, secondo noi quello che si vede in questo frame è un qualcosa di reale e NON un pohotoartifact (che poi si tratti di un fulmine - ipotesi tutt'altro che impossibile -; di una nuvoletta composta al 99,9% di ghiaccio d'acqua - e dunque dall'albedo altissima - o di una nave spaziale aliena in ricognizione - perchè no?!? - non ci è possibile dirlo).Mar 02, 2006
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Titan-W00013655.jpgThe "bright light" is gone54 visiteFrame immediatamente successivo a quello che evidenziava un luce bianca e brillante (8 pixels) negli strati superiori dell'atmosfera di Titano: ora tutto appare "normale". Si trattava dunque di un photoartifact o di un oggetto reale?
Caption originale:"W00013655.jpg was taken on February 27, 2006 and received on Earth February 27, 2006. The camera was pointing toward TITAN at approximately 32.110 Km away, and the image was taken using the CB3 and CL2 filters. This image has not been validated or calibrated".Mar 02, 2006
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Titan-W00013654.jpgA "bright light" in the clouds?55 visiteCerchiatura Bianca: la macchia bianca che vediamo fra le nuvole di Titano è un gruppo di 8 "dead-pixels" circondato da un grappolo di almeno una ventina di "bad-pixels" (e dunque uno dei soliti photoartifact), oppure si tratta di un oggetto luminosissimo il quale ha provocato la evidentissima sovraesposizione della zona in cui si trovava al tempo dello scatto?
Caption originale:"W00013654.jpg was taken on February 27, 2006 and received on Earth February 27, 2006. The camera was pointing toward TITAN at approximately 34.753 Km, and the image was taken using the CB3 and CL2 filters. This image has not been validated or calibrated".Mar 02, 2006
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Titan-PIA07707.jpgSmiling Titan...54 visiteThis infrared view shows features on the Leading Hemisphere of Titan, including the bright, crescent-shaped Hotei Arcus (right of center), which is also informally called "the Smile" by researchers.
The view is centered on the bright Region called Xanadu. Above center is the large crater Minerva, which is surrounded by darker material.
This image was taken with the Cassini spacecraft narrow-angle camera on Jan. 13, 2006 using a spectral filter sensitive to wavelengths of infrared light centered at 938 nnmts. The image was acquired at a distance of approx. 1,3 MKM (800.000 miles) from Titan and at a phase angle of 41°. Image scale is about 7 Km (approx. 5 miles) per pixel.Feb 23, 2006
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Titan_and_Tethys-PIA07705.jpgBright Brothers in the Night56 visiteCassini looks toward Tethys and its great crater Odysseus, while at the same time capturing veiled Titan in the distance (at left).
Titan is shrouded in a thick, smog-like atmosphere in which many small, potential impactors burn up before hitting the Planet's surface.
Crater-pocked Tethys has no such protective layer, although even a thick blanket of atmosphere would have done little good against the impactor that created Odysseus.
The eastern limb of Tethys is overexposed in this view.
The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Jan. 6, 2006, at a distance of approximately 4 MKM (about 2,5 MMs) from Titan and 2,7 MKM (about 1,7 MMs) from Tethys. The image scale is approx. 25 Km (about 16 miles) per pixel on Titan and approx. 16 Km (about 10 miles) per pixel on Tethys.Feb 19, 2006
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Titan-PIA07700.jpgThe Atmosphere of Titan54 visiteThe view of Titan (almost natural colors) has been greatly contrast-enhanced to better show some intriguing structure in the North of the Planet; such intriguing "clouds-structure" is also clearly visible in a violet light view (PIA07701) taken at about the same time.
The color view was created by combining images taken using red, green and blue spectral filters. The images were taken with the Cassini spacecraft wide-angle camera on Dec. 26, 2005, at a distance of approx. 193.000 Km (about 120.000 miles) from Titan and at a phase angle of 29°. The image scale is about 11 Km (roughly 7 miles) per pixel.Feb 14, 2006
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Titan-PIA07701~0.jpgThe atmosphere of Titan55 visiteThis view of Titan reveals structure in the moon's complex atmosphere. The geometry of the Cassini spacecraft's view of Titan during this flyby was similar to that of Voyager 1's pass in 1980.
The image was taken in visible violet light and shows the detached high haze layer that envelops Titan, with additional complexity to its structure in the far North. Some of this atmospheric structure is also visible in a color view (PIA07700) taken at about the same time..
The image was taken with the Cassini spacecraft wide-angle camera on Dec. 26, 2005, at a distance of approx. 194.000 Km (such as about 121.000 miles) from Titan and at a Sun-Titan-spacecraft, or phase, angle of 29°. The image scale is 11 Km (about 7 miles) per pixel.Feb 14, 2006
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Titan-Map-PIA02147.jpgGlobal Titan Map (Visual + IMS)56 visiteThis global infrared map of Titan was composed with data from Cassini's visual and infrared mapping spectrometer taken during the last two Titan flybys, on Dec. 26, 2005, and Jan. 15, 2006.
There are several important features to note in this Map:
1) the globe of Titan exhibits 2 major types of terrain: one is very bright, and a darker one seems to be concentrated near the Equator;
2) Titan has two very bright Regions: the large one known as Tui Reggio, located at approx. 25° South Lat. and 130° West Long., and the other as Hotei Arcus, at 20° South Lat. and 80° West Long. These regions are thought to be surface deposits, probably of volcanic origin, and may be water and/or carbon dioxide frozen from the volcanic vapor; the western margins of Tui Reggio have a complex flow-like structure consistent with eruptive phenomena;
3) the reddish feature at the South Pole is Titan's South Polar cloud system, which was very bright during the December flyby;
4) The Sinlap Crater is clearly visible at approx. 13° North Lat. and 16° West Long. The poorly resolved Regions between Longitudes of 30° and 150° East will be filled in during subsequent flybys. Feb 11, 2006
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Titan-Full_Disk-PIA02145-3.jpgTitan: Visual + IMS (3)56 visitenessun commentoFeb 11, 2006
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Titan-Full_Disk-PIA02145-2.jpgTitan: Visual + IMS (2)55 visiteIn the December (2) mosaic, a North Polar hood that is bright at 5 microns is visible. Its composition is unknown.
The North Polar hood is barely seen in the October (1) and January (3) data.
Visible in the October and December images just South of the Equator is Tui Reggio, a Region nicknamed the "chevron". This Region is very bright at 5 microns and is among the brightest features on Titan at that wavelength.
Tui Reggio is thought to be a surface deposit, probably of volcanic origin, and may be water and/or carbon dioxide frozen from the vapor.
The December flyby data show that the western margins of Tui Reggio have a complex flow-like character consistent with eruptive phenomena.Feb 11, 2006
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Titan-Full_Disk-PIA02145-1.jpgTitan: Visual + IMS (1)56 visiteThe three mosaics shown here were composed with data from Cassini's visual and infrared mapping spectrometer taken during the last 3 Titan flybys, on Oct. 28, 2005 (1), Dec. 26, 2005 (2), and Jan. 15, 2006 (3).
These false-color images were constructed from images taken at the following wavelengths: 1,6 microns (blue), 2,01 (green), and 5 microns (red).
The viewing geometry of the December flyby is roughly on Titan's opposite Hemisphere from the flybys in October and January.
There are several important features to note in the images. The first is that the South Polar cloud system was very bright during the December flyby, while during the October and January flybys, it is barely visible, indicating that the atmosphere over Titan's South Pole is very dynamic.Feb 11, 2006
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