This visible light view shows the disk of Titan in the foreground and a crescent of the icy moon Rhea through Titan's upper atmosphere in the background. Rhea emerges after being occulted by Saturn's largest moon.
The image was acquired with the Imaging Science Subsystem narrow-angle camera of the Cassini spacecraft on October 27, 2009.
The Orange Moon is located roughly 1 million kilometers (621,000 miles) from the Cassini probe in this view and Rhea appears, roughly, 2.3 million kilometers (1.4 million miles) from the spacecraft. The illuminated terrain, observed here, is on the trailing hemispheres of Titan and Rhea.
Titan is 5,150 kilometers or 3,200 miles in diameter and Rhea is only 1,528 kilometers or 949 miles in diameter. Titan moves farther from Saturn than Rhea. The semi-major axis of Titan from Saturn is roughly 1,221,870 km or 760,000 miles and the semi-major axis of Rhea from Saturn is about 527,108 km or 329,000 miles.
This kind of observation with one planetary body or moon passing close to or in front of another represents an opportunity for scientists to refine their understanding of the orbits of Saturn's satellites.
This visible light image clearly unveils the high altitude detached haze layer of Titan's deep, opaque and complex atmosphere. The UV light from the Sun undoubtedly plays a key role in the formation of the haze in Titan's upper atmosphere.

Credit: NASA/JPL/Space Science Institute

This infrared view of Titan's disk reveals the first glint from a liquid body. In the upper part of the disk, in the northern hemisphere of Saturn's largest moon, one can clearly observe a flash of sunlight which is the outcome of a light reflection on a smooth or mirror-like surface. This phenomenon is known as a specular reflection.
The image was acquired by the Cassini spacecraft in its 59th flyby of Titan on July 8, 2009 at a distance of approximately 200,000 kilometers or 120,000 miles. The Visual and Infrared Mapping Spectrometer or VIMS allowed scientists to identify the glint in the infrared spectrum of light since it goes through Titan's atmosphere. The view was generated on the basis of wavelength data in the 5 micron range. Most of the visible light spectrum is scattered and absorbed by the murky atmosphere of the Orange Moon, which explains why the human eye can't see the surface from outer space. Image processing was performed at the German Aerospace Center in Berlin and the University of Arizona in Tucson.
The reflection of solar light appears to be located in the southern shoreline of the largest pool of liquid in Titan's northern hemisphere, "Kraken Mare". Scientists compared this view to radar and near-infrared images obtained from 2006 to 2008 to infer where the glint took shape. It appears that the flash came from a portion of the sea around 71 degrees north latitude and 337 degrees west longitude. Let's note that Kraken Mare, probably made of ethane and methane, covers approximately 400,000 square kilometers or about 150,000 square miles and this liquid body is likely largely bigger in surface area than Ontario Lacus, the giant lake of Titan's south polar region.
Until August 2009 and the spring equinox in the northern hemisphere, the northern hemisphere was experiencing the winter period which lasts no less than 7 years on Titan and had been undergoing darkness for almost 15 years. With the new season approaching, however, the sun started to illuminate the region of Kraken Mare again thanks to the change in the viewing geometry, triggering this recent glint spotted by the Cassini probe.

Credit: NASA/JPL/University of Arizona/DLR

This near-infrared view shows a low-albedo area of Titan known as Senkyo. This region which appears mostly dark is located near the equator of Saturn's largest moon. This portion appears on the Saturn-facing side of the Orange Moon and the region is centered on terrain at 1 degree south latitude, 345 degrees west longitude. North appears to the top of the view and is tilted 10 degrees to the right.
This portion of Titan's low latitudes was acquired with the Imaging Science Subsystem Narrow-Angle Camera of the Cassini probe on October 12, 2009 incorporating a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The view was obtained at a distance of about 296,000 kilometers (184,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 11 degrees.
The bright patches are more reflective than the dark areas and are probably made of icy materials such as water ice or frozen carbon dioxide. The dark areas likely host dune fields which are common in the low latitudes of the moon where prevailing winds seem relatively strong. A dark circular ring in the upper boundaries of a bright feature toward the center of the portion is likely the outcome of a meteoritic impact. This circular patch may also be a caldera or a cryovolcanic feature.

Credit: NASA/JPL/Space Science Institute

This near-infrared view of Titan's disk reveals the southern portion of what appears to be the largest body of liquids on Saturn's largest moon, named Kraken Mare.
The image was acquired with the ISS Wide-Angle Camera of the Cassini spacecraft on October 12, 2009 using a spectral filter sensitive to wavelengths of near-infrared radiation centered at 939 nanometers. The disk was obtained at a distance of about 252,000 kilometers (157,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 11 degrees. The hemisphere seen here corresponds to the Saturn-facing side of the satellite. North appears to the top of the disk and is inclined at 31 degrees to the right.
The equatorial and tropical areas appear mostly dark with portions of bright patches in the near-infrared spectrum. Seif dunes or longitudinal dune fields appear widespread in the low latitudes and they appear to be less reflective than the icy areas, appearing brighter or more reflective in this view of the disk. The eastern portion of the "H" of the dark patches of Fensal and Aztlan is clearly visible to the left and in the upper part of the disk. Fensal incorporating a circular bright patch is to the north of Aztlan. To the east of Aztlan, one can notice the dark albedo feature of Senkyo.
The high latitudes of the northern hemisphere display a myriad of lakes and seas. The largest pool of hydrocarbons, of which the southern portion is visible here, is Kraken Mare. The southern rims of this sea appear a little below 60 degrees north latitude and approximately between 330 degrees west longitude and 300 degrees west longitude.

Credit: NASA/JPL/Space Science Institute

This ultraviolet image of Titan's disk unveils the detached, high-altitude global haze layer of the deep, opaque and complex atmosphere of Saturn's largest moon.
The image was acquired with the ISS narrow-angle camera of the Cassini spacecraft on June 19, 2009 using a spectral filter sensitive to wavelengths of ultraviolet radiation centered at 338 nanometers. The outcome was obtained at a distance of about 1.3 million kilometers (808,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 141 degrees.
A small portion of the disk is illuminated because the lit terrain appears mostly on the opposite side of the globe which corresponds to the trailing hemisphere of Titan. Thus, the image is centered on the leading hemisphere of the icy moon and the probe looks down on the north pole of Titan.
The action of UV radiation from the Sun is believed to play a key role in the formation of the high-altitude haze of the atmosphere.

Credit: NASA/JPL/Space Science Institute

This natural color view of the Orange Moon, Titan, reveals the slight atmospheric dichotomy between the northern portion and the southern portion of the globe.
This global view was obtained with the ISS wide-angle camera of the Cassini probe on August 25, 2009 shortly after Saturn's August 2009 equinox, at a distance of about 174,000 kilometers (108,000 miles) from Saturn's largest moon. This natural color image is the outcome of views acquired using red, green and blue spectral filters. The three views were combined to generate the final disk. This view of the disk looks toward the Saturn-facing side of the "Opaque Moon". North appears to the top of the disk.
This global image of Saturn's largest moon unveils a slightly darker northern hemisphere and a slightly lighter southern hemisphere. Scientists are beginning to draw a relationship between this apparent hemispheric dichotomy and seasons. Seasons on Titan last approximately 7 years. The winter season in the northern hemisphere and the summer season in the southern hemisphere came to an end in August 2009. Spring is now coming in the northern hemisphere which will experience the Summer Solstice in May 2017. The border between the darker and lighter portions of the disk appears to run east-west and lies at about 10 degrees of latitude from the equator.
Specialists have detected that the winter hemisphere typically seems to gather more high-altitude haze, making it darker at shorter wavelengths (ultraviolet through blue) and brighter at infrared wavelengths. The switch between dark and bright areas happened over the course of a year or two around the last equinox. Scientists are paying a special attention to the atmospheric changes expected to occur with the new seasons in the southern and the northern hemisphere. It may help us better understand the mechanisms by which the high-altitude haze forms.

Credit: NASA/JPL/Space Science Institute

This global view of Titan's disk, taken in the ultraviolet spectrum, clearly shows the north polar hood of Saturn's largest moon. One can also notice the detached, high altitude haze layer in the upper part of the opaque atmosphere.
In this view, north appears in the dark area of the polar hood to the top and is inclined by 2 degrees to the left. The image was acquired with the ISS narrow-angle camera of the Cassini probe on August 13, 2009 using a spectral filter sensitive to wavelengths of ultraviolet radiation centered at 338 nanometers. The image was obtained at a distance of about 2.2 million kilometers (1.4 million miles) from the Orange Moon and at a Sun-Titan-probe, or phase, angle of 61 degrees.
The north polar region, currently leaving the summer season, is known to be a wet area with lakes, seas and rivers. A giant cloud formation, probably made of ethane, engulfing the north polar region has been recently identified.

Credit: NASA/JPL/Space Science Institute

This near-infrared view reveals a portion of the low-albedo feature Senkyo in Titan's southern hemisphere. The area is centered at 28 degrees south latitude, 334 degrees west longitude and it lies on the trailing hemisphere of Saturn's largest moon.
The image was obtained on July 9, 2009 with the ISS narrow-angle camera of the Cassini spacecraft, using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The image was captured at a distance of about 251,000 kilometers (156,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 27 degrees.
This area which consists of bright and dark topographic features is located in the south of Senkyo. Linear or curvy streaks can be identified in the lower left of the view. Their shape may be related to the action of winds which seem to be relatively strong in the tropics. A dark, circular feature in the lower part of the view may be the outcome of a meteoritic impact.

Image Credit: NASA/JPL/Space Science Institute

This global view of Titan's disk unveils the halo-like ring taking shape in the upper hazes of the deep and opaque atmosphere of Saturn's largest moon.
The image was obtained with the ISS narrow-angle camera of the Cassini probe on July 5, 2009 using a spectral filter sensitive to wavelengths of ultraviolet radiations centered at 338 nanometers. The view was acquired at a distance of about 1.3 million kilometers (808,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 148 degrees.
The portion of the disk which is darkened or not illuminated appears to be on the leading hemisphere of the giant moon. On the other hand, illuminated or lit terrain observed here appears to be on the trailing hemisphere and anti-Saturn side of Titan. The north pole turns out to be located on the terminator between the illuminated and unilluminated portions of the satellite. The north pole is tilted 11 degrees to the right in this view.
Titan's atmosphere appears to be particularly complex with a multitude of detached haze layers. The Huygens probe which landed relatively close to the equator in the southern hemisphere recorded an atmospheric pressure on the surface of about 1467 hPa.

Image Credit: NASA/JPL/Space Science Institute

This view of Titan's disk clearly shows the radar-dark regions of Fensal and Aztlan forming a topographic H along the equatorial region.
The image was obtained with the ISS narrow-angle camera of the Cassini probe on June 9, 2009 using a spectral filter sensitive to wavelengths of near-infrared radiation centered at 938 nanometers. The shot was captured at a distance of about 1.2 million kilometers (746,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 26 degrees. The camera looks toward the Saturn-facing side of the satellite. North is to the top and inclined 16 degrees to the right.
The dark area Fensal, located in the upper part of the disk was named after the magnificent mansion of Frigga in Norse Mythology. The other dark area of the "H", Aztlan, was named after the mythical land from which the Aztecs believed they migrated towards Mexico. To the right of the radar-dark H, one can identify the low-albedo features Aaru and Senkyo, as well. Aaru was named after the Egyptian abode of the blessed dead and Senkyo was named after the Japanese ideal realm of aloofness and serenity, freedom from wordly cares and death.

Image source: NASA / JPL/Space Science Institute

This global view of Titan's disk unveils a cloud outburst in Titan's tropics. The near-infrared image, taken in the 2.12 micron wavelength, was obtained on April 14, 2008 (UTC) with the Gemini North Telescope using adaptive optics. Saturn's largest moon is approximately 0.8 arcsecond across in this view.
The bright patch corresponds to the significant cloud formation spotted in the tropical area. The presence of massive cloud systems in the low latitudes of Titan appears to be infrequent. Observations of Titan's disk from terrestrial telescopes reveal that this dramatic increase in cloud cover at a low latitude is exceptional and perhaps, unprecedented.
The occasional development of significant cloud systems in the arid tropics may account for the presence of the drainage channels observed from the Huygens probe. It may also explain the Sand Seas or the Seif Dunes shaped by prevailing winds and extending over long distances along the equator.
The origin of the cloud outburst in the tropics which appears to have engendered other clouds towards the south polar region and close to the equator is unknown. Some researchers suggest that it might be linked to an eruption of a cryovolcano in the area.

Image Credit: Gemini Observatory/AURA/Henry Roe, Lowell Observatory/Emily Schaller, Institute for Astronomy, University of Hawai'i

This radar mosaic made of several swaths acquired by the Synthetic-Aperture Radar (SAR) of the Radar Mapper aboard the Cassini probe features a complex landscape in Titan's south polar region. The radar-dark region is several hundred kilometers across. The area is centered near 82 degrees south, 205 degrees west and it is composed of data from the following Titan flybys: T39, T55, T57, T58 and T59. These radar swaths were collected between December 2007 and July 2009. The interpretation of the radar features must take into account variations in resolution and illumination angle of the swaths which engender changes in appearance. Thus, the edges between the swaths can be clearly identified and similar surface features are likely to show a different albedo depending on the resolution and on the illumination angle of the swath. The overall view enables us, however, to discern the general landscape features.
The area seems to be dominated by a radar-dark basin surrounded by relatively bright rims. The darkness of the main landscape feature implies that the area is probably humid but it seems unlikely that the basin is, currently, completely filled with liquid hydrocarbons, simply because the level of darkness appears insufficient and some darkness variations can be spotted within the basin. Some researchers suggest that this basin is a dried-out sea or lake which will be replenished in the upcoming winter period. Currently, the summer period is coming to an end in the south polar region and the summer is thought to be a dry period on Titan.
The bright margins surrounding the dark area are probably associated with a shoreline and hills which drain hydrocarbon liquids resulting from rainfalls into the large basin. The bright features often show some linear extensions from the basin, perpendicular to it: this may be explained by the pressure exerted by the liquids from the sea against the shoreline or it may simply be the outcome of the action of liquid streams from the sea which erode and expel the solid material of the crust outward.
The round structure of the dark area may also be explained by a meteoritic impact which would have generated those bright extensions. Some bright channels in the west of the basin suggest that flows of molten material may have occured in the past. A dark channel in the east of the basin between brigh features may still be filled with liquid hydrocarbons due to its high level of darkness.
The oval, dark patch in the south west of the mosaic is probably filled with liquid hydrocarbons since it appears uniformly dark. Some round patches in the west may have been generated by meteorites. In the north, round bays appear suggesting erosional processes engendered by the potential liquids of the sea.

Image source: NASA / JPL

This natural color view of Saturn's largest moon, Titan, reveals night and day in the northern hemisphere plunged into the winter period. The shot was obtained with the ISS wide-angle camera onboard the Cassini spacecraft on June 6, 2009 at a distance of about 194,000 kilometers (121,000 miles) from the Orange Moon. Views captured using red, green and blue spectral filters were combined to generate this outcome. The view of the disk is centered at 49 degrees north latitude, 243 degrees west longitude. The north pole is tilted approximately 23 degrees to the left and it is located on the terminator above and to the left of the center of the shot.
Titan appears to be the second largest moon in the Solar System: this icy world is a little smaller than Ganymede with a diameter of 5150 kilometers or 3200 miles. Its deep, dense and opaque atmosphere hides the view of Titan's landscape from outer space. This natural color image of the hazy moon enables us to discern the outer limits of the atmosphere dominated by a thin layer with a blue hue. The winter period in the northern hemisphere is coming to an end: the vernal equinox will occur in August 2009.

Image source: NASA / JPL / Space Science Institute

This near-infrared view of Titan's disk was captured with the Cassini probe narrow-angle camera on May 25, 2009. The image was obtained at a distance of about 1.3 million kilometers (808,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 25 degrees, using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers.North appears to the top and is inclined 38 degrees to the left.
The illuminated area, here, which is mostly on the leading hemisphere of Saturn's largest moon unveils, notably, Fensal and Aztlan, two optically-dark areas located in the equatorial region. Fensal and Aztlan hold their name from enchanted places or paradises found in legends and myths taking shape in various cultures worldwide. Fensal, the dark elongated area to the left, which appears mostly above the equator, was named after a magnificent mansion in Norse mythology. Aztlan, the elongated area to the right of Fensal, located a little below the equator was named after an Aztec mythical land. Below the "H" of Fensal and Aztlan, separated by the bright patch of Quivira, the optically-bright Tsegihi, can be identified, as well.

Image source: NASA / JPL / Space Science Institute

This radar portion of Titan's south polar region, obtained by the Radar Mapper of the Cassini probe on June 22, 2009, shows an intriguing large basin at its center. The view is centered near 76.5 degrees south latitude, 213 degrees west longitude and it covers an area of 190 by 140 kilometers (118 to 87 miles). The basin is estimated to be 100 kilometers wide (62 miles). The radar illumination comes from the left, and the incidence angle is approximately 45 degrees. The upper part of the basin is cut by an horizontal white corridor which corresponds to a data gap in the preliminary version.
The large basin is characterized by radar-dark rims in its western part with radar-dark channels, fractures or grooves breaking the apparent regularity of the oval shape of the basin. Differences in radar reflectivity inside the basin suggest an irregular topography and the particularly dark and uniform areas may be filled with liquid hydrocarbons such as methane, ethane or propane. The brighter portions of the basin might be elevated terrain. The left rims of the basin might be associated with cliffs or fractures. The area of the basin appears to be located to the south-west of Ontario Lacus.
There are several hypotheses for the origin of this basin. It might be a cryovolcanic caldera resulting from the collapse of the volcanic terrain after eruptions of cryolava. The topography of the basin might also be the outcome of a meteoritic impact. If so, its shape has been modified over time due to erosional processes: subsurface liquids as well as sedimentary materials are likely to play a key role in the formation of the basin. The nature of the soil is still unknown but it's likely that it contains complex hydrocarbons and molecules such as acetylene (ethyne, C2H2), water ice or frozen carbon dioxide. If there is a subsurface ocean of methane, one can also envisage the possibility that the basin results from the collapse of an icy shell floating above the ocean.

Image source: NASA / JPL

This global view of Titan's disk was obtained in violet light with the ISS Wide-Angle Camera of the Cassini probe on May 21, 2009. The image was captured at a distance of about 147,000 kilometers (91,000 miles) from Saturn's largest moon and at a Sun-Titan-spacecraft, or phase, angle of 121 degrees. The exposed area observed here is on the trailing hemisphere of the Orange Moon, which is facing Saturn. This shot is centered on 54 degrees north latitude, 251 degrees west longitude. The north pole of the Hazy Moon is located on the terminator approximately one-third of the way inward from the upper part of the view.
This view of Titan's opaque atmosphere notably reveals the detached haze layer which glides in the upper part of the complex and deep blanket of gases covering the icy sphere. The atmospheric hazes take the shape of a halo in the external part of the atmosphere. The ultra-violet radiations from the Sun are likely to play a key role in the formation of the haze. Let's recall that Titan's atmosphere is heavier and more dense than Earth's atmosphere: the Huygens probe recorded a surface pressure of about 1467 hPa in the landing site on January 14, 2005.

Image source: NASA / JPL / Space Science Institute

This near-infrared view of Saturn's largest moon, Titan, notably reveals the dark region of Senkyo in the center of the image. Senkyo can be spotted just south of the equator at a longitude of about 330 degrees west. Geographically, Senkyo lies between the dark regions of Fensal and Aztlan to the west and the dark region of Belet to the east.
The view was captured with the Cassini probe narrow-angle camera on March 21, 2009 using a spectral filter sensitive to wavelengths of near-infrared radiation centered at 938 nanometers. The image was acquired at a distance of about 994,000 kilometers (618,000 miles) from the Hazy Moon and at a Sun-Titan-spacecraft, or phase, angle of 63 degrees. North appears toward the top and is tilted 6 degrees to the left. Illuminated terrain observed here is on the Saturn-facing side of the Orange Moon.
Longitudinal dune fields or parallel and linear dune fields over long distances appear widespread in the dark, equatorial regions of Titan and Senkyo is probably dominated by those kinds of Seif Dunes, carved by prevailing winds.

Image source: NASA / JPL / Space Science Institute

This radar image of Titan's equatorial region and its sand dune features was obtained by the radar mapper of the Cassini spacecraft on May 21, 2009 from an altitude of 965 kilometers ( around 600 miles ). The geographical portion is 225 kilometers wide ( 140 miles ) and 636 kilometers long ( 395 miles ), centered just north of the equator at 0.5 degrees north latitude and 154.2 degrees west longitude. North appears to the right in this view and radar illumination comes from the top at an incidence angle of 24 degrees.
The view clearly reveals the famous "Cat Scratches", widespread along the equator and at low latitudes. Those topographic or radar features which extend over long distances are likely dune fields similar to Seif Dunes encountered on Earth, in the Namib Desert, for instance. The parallel dunes appear to be carved by prevailing winds. The dunes are probably made of organic material, consisting of sand-sized particles.
On our planet, dunes preferentially take shape in low-lying areas without any major topographic obstacles: hills and mountains act as obstacles to the movement of sand-sized particles. The bright patches in this radar view don't show the dune patterns identified in the radar-dark area. They are interpreted as topographic obstacles or elevated terrains that block the dunes: they are likely made up of a more reflective material ( Water ice, frozen CO2...) than the dark areas surrounding them. The bright patch to the right seems to be partly crossed by linear sand dunes coming from the top of the view: that may be explained by the presence of a valley or a low-lying area in the bright terrain, allowing the winds to transport the sand-sized particles into the radar-bright area.
Differences in sand supply, in winds and topographic variations account for the significant variations in spacing and density. The irregular bright patch to the left of the view is surrounded by roughly symmetrical dunes implying that the bright patch is responsible for generating the pattern. The way the dunes are deflected by the topographic obstacles and the distribution of the dunes across the landscape ( drifts...) suggest that prevailing winds blow from the upper part to the lower part of the geographical portion.

Image source: NASA / JPL

This radar image obtained by the radar mapper of the Cassini probe on May 21, 2009 shows complex and unique canyon systems in the high latitudes of Titan's southern hemisphere. The view is centered at 71 degrees south latitude and 240 degrees west longitude. This geographic portion is 335 kilometers long ( 208 miles ) and 289 kilometers wide ( 179 miles ). The region was illuminated from the top of the view at 18 degrees incidence angle.
Canyons or gorges often take shape via erosional processes engendered by river flows. It seems here that an ample flow of liquid methane rivers has carved the wide canyons into older terrain. The radar-bright features in the lower part of the view which present linear edges or rims, parallel to the orientation of the assumed channel, are interpreted as high cliffs and broken bedrock. The canyons or gorges which appear dark in the radar image show multiple wide tributaries from the left to the right. One can assume that fluids ran from high plateaus on the right to lowland areas on the left. It appears that rainfall also plays a key role in eroding the surface: lots of cloud systems have been identified in the high latitudes of Titan's south polar region. Pools of liquid such as "Ontario Lacus" are probably closely linked to massive rainfall from the large cloud formations which specifically take shape in that area, at least during the summer season.
The dark appearance of the wide channels captured by Cassini's synthetic aperture radar is probably associated with a smooth surface made of fine-grained materials. The orientation of the channels has been influenced by the nature of the soil and by winds which blow from the bottom left of the view toward the left center. The dark material of the gorges was later carved by massive flows of what is thought to be liquid methane. This topographic area is typical of other areas scanned near Titan's south pole in other flybys.
The erosional processes observed in that area are reminiscent of erosional processes of most canyons or gorges on our planet, generated by rivers or rainfalls. One can draw a parallel, notably, with the Grand Canyon in Arizona carved by the Colorado River or the Verdon Gorge in the south-east of France. However, let's note that the famous canyon on Mars "Valles Marineris" is likely different in nature: it might have been generated by tectonic forces.

Image source: NASA / JPL

This global view of Saturn's largest moon Titan is a color composite revealing large cloud formations in the high latitudes of Titan's southern hemisphere. Cloud features are discerned in the infrared spectrum. The views were obtained by Cassini's Visual and Infrared Mapping Spectrometer during the T27 flyby of the Orange Moon on March 26, 2007. The inset which is zoomed in on the right of the disk shows the large cloud burst of clouds incorporating red shown at a 5-micron wavelength, green at 2.7 microns, and blue at 2 microns. The rest of the disk represents an infrared color mosaic made of red at 5 microns, green at 2 microns and blue at 1.3 microns.
Scientists who have analysed Titan's murky atmosphere and identified more than 200 clouds for three-and-a-half years, between July 2004 and December 2007, note some similarities in the way the clouds form and move on Earth and on Titan. However,the Cassini data indicates that in Titan's atmosphere, the clouds turn out to develop and move in a much slower, more lingering fashion. The distribution of clouds on the globe is roughly consistent with global circulation models proposed by scientists. Nevertheless, the presence of active, large cloud formations in the south polar region at the end of the summer season appears surprising. The meteorology of Titan's southern hemisphere is still dynamic in 2007. The climate models imply that these clouds should have faded out since 2005. The clouds, here, which appear in white-reddish tones, are located between about 60 degrees south latitude and a little more than 80 degrees south latitude.
The infrared and radar images of Titan's south polar region and Titan's north polar region show, in the same areas, large cloud formations and pools of liquids. The concentration of clouds and assumed liquid hydrocarbons in the polar regions is not fully understood. Cassini's extended mission which will come to an end in the fall of 2010 will bring new opportunities to add some clues to this meteorological puzzle.

Image source: NASA / JPL / University of Arizona / University of Nantes

This mosaic of false-color views of Titan reveals a multitude of elongated cloud formations between 40 degrees south latitude and 50 degrees south latitude. The color frames were obtained by Cassini's Visual and Infrared Mapping Spectrometer during a close flyby ( called the T17 Flyby) of the Orange Moon on September 7, 2006. Each frame is a color composite made of red shown at the 2-micron wavelength, green shown at 1.6 microns, and blue shown at 2.8 microns. The rest of the globe surrounding the three frames is represented with an infrared color mosaic made of red at 5 microns , green at 2 microns and blue at 1.3 microns.
Titan's atmosphere has been closely monitored by Cassini scientists for three-and-a-half years, between July 2004 and December 2007 unveiling more than 200 clouds. Their distribution on the globe is consistent with global circulation models proposed by scientists. However, there are differences in the timing of their movements: the clouds form and move in a similiar way to the clouds on our planet, but in a much slower, more lingering way, as the views of NASA's Cassini probe suggest. As the end of the summer season is approaching in the southern hemisphere, clouds still appear in that area.
The infrared views clearly show elongated mid-latitude clouds in bright bluish colors. They are reminiscent of Cirrus clouds on the Earth. Those cloud formations are still present and dynamic in 2006-2007. The climate models imply that they should have faded out since 2005. The seasons on Titan are very long. As a result, further observations are needed to get a general understanding of the atmospheric distribution and dynamics of Titan clouds. The Cassini spacecraft will have some opportunities until the fall of 2010 during Cassini's extended mission.

Image source: NASA / JPL / University of Arizona / University of Nantes

This near-infrared view of Saturn's largest moon, Titan, reveals some cirrus-like cloud formations at mid-latitudes in the southern hemisphere. The view was captured with the ISS ( Imaging Science Subsystem ) narrow-angle camera of the Cassini probe on March 24, 2009 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The image was acquired at a distance of about 1.1 million kilometers (684,000 miles) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 78 degrees. The illuminated terrain, here, appears on the leading hemisphere of Titan.
One can notice, notably, bright streaks in the lower left of the crescent: they turn out to be tropospheric clouds moving between 45 and 55 degrees south latitude. They are reminiscent of cirrus-like clouds on our blue planet. Their orientation appears to be east-west. The south pole can be identified near the terminator approximately a quarter of the way inward from the planet's limb in the lower part of the disk. A discernable landscape feature, in this view is the optically dark H of Fensal and Aztlan in the upper part of the crescent. Both regions lie in the equatorial area.

Image source: NASA / JPL / Space Science Institute

This view of Saturn's largest moon, Titan, reveals the complexity of its deep and opaque atmosphere. This crescent was obtained in visible violet light with the ISS wide-angle camera from the Cassini probe on March 27, 2009. The image was taken at a distance of about 196,000 kilometers ( 122,000 miles ) from the Orange Moon and at a Sun-Titan-spacecraft, or phase, angle of 106 degrees. The largest part of the lit terrain observed here is on the anti-Saturn side of Titan. The north pole of the satellite is unveiled, surrounded by several parallel atmospheric bands in the high northern latitudes: in fact, it is located near the terminator approximately a quarter of the way inward from moon's limb in the upper part of the view.
The atmospheric banding clearly identified in the high northern latitudes is reminiscent of atmospheric banding occuring in the atmospheres of Gas Giants, Saturn, Jupiter or Neptune. Some near-infrared or infrared views of Titan's north polar region have revealed a polar hood made of ethane clouds engulfing the entire north polar area. The upper part of the atmosphere unveils multiple detached haze layers and this global view shows a detached gas blanket in the outer limit of the atmosphere, creating the appearance of a halo around Saturn's largest satellite.

Image source: NASA / JPL / Space Science Institute

This near-infrared view of Titan's disk shows the Saturn-facing hemisphere of the moon and a large portion of the south polar region. North appears up and is inclined by 27 degrees to the right. This global view from the Cassini spacecraft was obtained with the narrow-angle camera of the Imaging Science Subsystem ( ISS ) on February 15, 2009 using a spectral filter sensitive to wavelengths of near-infrared radiation centered at 938 nanometers. The image was captured at a distance of about 1.2 million kilometers ( 746,000 miles ) from Saturn's largest moon and at a Sun-Titan-spacecraft, or phase, angle of 55 degrees.
In the upper portion of the illuminated side of the disk, along the equatorial area, one can notice, notably, the optically dark regions of Fensal and Aztlan which form a "laid H", parallel to the equator. Below Fensal / Quivira / Aztlan, the optically bright region of Tsegihi clearly appears, centered at about 30 degrees south latitude and 30 degrees west longitude. To the east of Fensal / Aztlan, one can also identify the optically dark region of Senkyo.
In the lower portion of the illuminated disk, below Tsegihi, in the south polar region, one can spot the optically dark region of Mezzoramia which extends between approximately 60 and 75 degrees south latitude. Mezzoramia is believed to be a wet area, likely filled with liquids of hydrocarbons due to the presence of frequent large cloud formations in the south polar region. A bright streak to the right of Mezzoramia can be discerned: it might be a Cirrus-like cloud formation similar to those found at mid-latitudes.
Titan's south polar region, viewed at the end of the summer season, seems to be a relatively wet area with its "lake districts" and what is believed to be the largest pool of liquids identified so far in the area " Ontario Lacus". The lakes are probably composed of mixtures of methane and ethane.

Image source: NASA / JPL / Space Science Institute

The outer shell of Titan's atmosphere is clearly identified in these contrast-enhanced views of the Saturn-facing side of the moon. North is orientated to the top and is inclined at 45 degrees to the left. The full color views of the orange satellite were obtained on the basis of images using and combining red, green and blue spectral filters. The phase angle or Sun-Titan-spacecraft angle is 157 degrees which is particularly high. The views were captured at a distance of about 1.8 million kilometers ( 1.1 million miles ) from Saturn's largest moon.
Each view of Titan's disk has been contrast enhanced to make it easier to identify atmospheric features such as the blue outer layer. The color of the right image has been processed, computer enhanced to bring out the outer haze blanket. In spite of the high phase angle, an entire ring of light appears thanks to scattering of solar radiations in Titan's deep and thick atmosphere. A typical moon with no atmosphere like Europa or Rhea would have appeared in this viewing geometry only as a lit crescent.
Besides, Titan's atmosphere appears exotic ( with mixtures of organic compounds or hydrocarbons ) and complex with clouds and multiple layers of haze in the upper atmosphere. On the landing site, where the Huygens probe was parachuted, the atmospheric pressure was close to 1.5 bars which is about 50% higher than the mean atmospheric pressure at sea level on the Earth.

Image source: NASA / JPL / Space Science Institute

This set of infrared images shows Hotei Arcus, a region of Titan's southern hemisphere suspected to be volcanically active. The representations are based on the same view. The top view corresponds to the view without annotations or markings. The middle view indicates the geographic scale and the direction of the north. The bottom view uses artificial colors and red markings to delimitate a region that is chemically distinct from its surroundings, pointing at a potentially, recent volcanic activity. The infrared view was obtained by the Cassini's Visual And Infrared Mapping Spectrometer ( VIMS ) on November 19, 2008 at a distance of 29,000 kilometers ( 18,000 miles ).
In the global infrared or near-infrared view, Hotei Arcus appears as a bright arc. Here, one can observe that the south portion of Hotei Arcus is dominated by mountains or elevated terrains as confirmed by the radar views. One of the striking features of this area is that changes in brightness have been recorded several times during the last four hours. Brightness variations combined with radar bright channels suggest that cryovolcanic activity is probably occuring or has likely recently occured. The most recent flows of molten material may be found in the portion of the red markings due to chemical differences with the surrounding landscape.
Scientists argue that brightness changes are consistent with transient deposits of ammonia frost on the soil. Other materials could account for brightness changes. Therefore, other hypothesis have to be considered. Water, carbon dioxide, nitrogen and ammonia are believed to be important components in the interior of the orange moon.
The global infrared views also suggest that the area of Hotei Arcus could have undergone a meteoritic impact. Likewise, the infrared feature could be a caldera or a volcanic crater. If there is a hidden ocean beneath the surface and if there has been a meteoritic event in that area, the thinner crust resulting from the impact is likely to generate fractures or upwelling of liquids from the hidden ocean...

Image source: NASA / JPL / University of Arizona

This near-infrared view showing the Saturn moons Titan and Dione was obtained on January 28, 2009 with the ISS wide-angle camera of the Cassini spacecraft. The image was captured at a distance of about 2.3 million kilometers ( 1.4 million miles ) from Titan with a Sun-Titan-spacecraft, or phase, angle of 44 degrees. It was taken using a spectral filter sensitive to wavelengths of near-infrared light centered at 939 nanometers. Titan is the globe in the lower part of the view. Its geographic north is up and rotated 3 degrees to the left. The eye sees the Saturn-facing side of Titan and the leading hemisphere of Dione.
Saturn's largest moon Titan orbits Saturn at a mean distance of about 1,221,850 km ( 763,656 miles ) from the ringed planet. Its diameter is 5,150 kilometers or 3,200 miles. Dione moves closer to Saturn at a mean distance of 377,000 kilometers ( 235,625 miles ) from the Gas Giant and it is well smaller than Titan with a diameter of 1,123 kilometers or 698 miles.
Light and dark areas on Dione can be discerned in this view, revealing the moon's fractured surface. Contrary to Titan, Dione has no atmosphere to protect its surface from meteorites. The image of Titan's disk reveals the optically dark region of Senkyo which lies between the optically darks areas of Fensal / Aztlan and Belet.

Image source: NASA / JPL / Space Science Institute

This composite image shows a portion of the region of Hotei Arcus in the south east of the optically bright Xanadu. The black and white view at the top corresponds to a radar view of the area taken by the radar mapper of the Cassini spacecraft during the T41 flyby on February 22, 2008. This radar image is converted into a topographic map appearing with colors to reveal variations in altitude as shown in the lower part of the image. 3D data was inferred from two radar views of the same region during the T41 flyby on February 22, 2008 and the T43 flyby on May 12, 2008. The color bar at left provides the scale of altitude from the lowest altitude of -650 meters associated with the purple or violet color and the highest altitude of -150 meters below zero elevation associated with the red color. One admits that zero elevation is equal to a distance of 2,575 kilometers ( 1,600 miles ) from the center of Titan, which corresponds, approximately, to the average radius of Saturn's largest moon. The maps are represented in equirectangular projection with north to the top.
This area of the southern hemisphere is centered near 30 degrees south latitude, 83 degrees west longitude, and is approximately 860 kilometers ( 530 miles ) across. The radar and topographic views make it difficult to clearly discern the topographic structure of Hotei Arcus and its bright circular edges that are clearly identified in the global infrared or near-infrared images. The topographic map shows that the total range of relief from the lowest terrain appearing in purple to the highest hills, mountains or plateaus appearing in red is around 500 meters ( approximately 1,600 feet ). One of the intriguing features in the area is the presence of radar-bright channels generally originating from hills or elevated terrains. Is it linked to cryovolcanism or rains of hydrocarbons ? Or is it linked to a meteoritic impact ?
Most channels, probably related to flows of liquids, have bright tops and radar-dark margins and appear to be 100 to 200 meters ( 300 to 600 feet ) thick. The presumed flows have apparently taken shape on low slopes. Therefore, if one considers the weak slope, the thickness and the shape of the channels, it is likely that the material was at least as viscous ( stiff ) as basaltic lava on our own planet. One can notice, moreover, a branched channel to the south. The channels which are connected seem to run from the mountains or hills toward a "topographic trap" that is a relatively low and uniform land at about -650 meters below zero elevation. One can note however that the slope is relatively weak which implies that the fluids must be or must have been less viscous than basaltic lava. It may rather be linked to liquid methane or ethane provided by rainfalls. Most channels tend to disappear in the topographic traps. If this region is volcanically active or if it regularly undergoes rainfalls, one can hope that further radar views of the area will bring precious information or clues on the identity of the flows.

Image source: NASA / JPL / USGS

This composite image presenting intriguing landscape features in Titan's northern hemisphere is based on radar data obtained by the radar mapper onboard the Cassini spacecraft. Stereo views of this radar strip were generated by using two radar images of the same region captured during the Ta flyby on October 26, 2004 and the T23 flyby on January 13, 2007.
The black and white portion at the top corresponds to the radar view acquired by the radar mapper during the Ta flyby. The same view of the region is presented below with color coding to provide elevations, as shown by the color bar at left. This topographic map which brings 3D information to the observer shows that the total range of relief from purple ( low ) to red ( high ) appears to represent 1,000 meters ( around 3,300 feet ) from -1,200 meters to -200 meters below zero elevation.
The radar strip is centered near 50 degrees north latitude and 80 degrees west longitude above Menrva. The region is approximately 1,480 kilometers ( 920 miles ) across and the maps are represented in equirectangular projection with north to the top.
One of the most striking features in the radar view is the roughly circular and uniform patch in the western part of the image: this landscape feature about 180 kilometers wide ( 100 miles ) is known as Ganesa Macula. At first sight, it is reminiscent of steep-sided volcanic domes or pan-cake shaped domes on Venus that were spotted with the NASA Magellan orbiter in the 1990s. The artist Michael Carrroll had represented in his painting Ganesa Macula as a cryovolcano similar in its shape to the Venusian volcanoes, with remnants of a bright, frozen lava flow.
The new topographic map based on stereo data is not consistent with the previous hypothesis of the volcanic dome. The circular patch doesn't appear to be a dome. The western part of Ganesa Macula is dominated by relatively lowlands well below zero elevation. The eastern part of Ganesa Macula is made of elevated terrain and unveils a topographic wall in the rims of the circular shape. The highest land reaching an altitude of about 200 meters above zero elevation is located close to the eastern rims of Ganesa Macula. Thus, contrary to what was initially believed, the bright dot or patch in the center of the circular shape, in the radar view, is not a peak. It is rather a low land. The maximum relief in Ganesa Macula turns out to culminate at approximately 1,200 meters ( 4,000 feet ).
Ganesa Macula could be or could have been a volcanic crater or a caldera. However, Ganesa Macula could also be the outcome of a meteoritic impact. One can notice, notably, that some bright channels are connected to the central patch of the circular shape: some flows coming from higher lands seem to have run toward the lowest land in the center of Ganesa Macula and that's not the opposite as initially believed.
Beyond Ganesa Macula, to the east, relatively lowlands alternate with hills or mountains: the violet or purple patches indicate low-lands which can be as low as 1,200 meters ( 4,000 feet ) below zero elevation. Another topographic wall with a north-south direction follows. To the east of these highlands appear relatively uniform lowlands which seem to be made up of a bright material, a flow deposit resulting from flows of liquid coming from the west as suggest the two triangular fan structures deriving from the second topographic wall.
The large area with the radar-bright material and the channels is known as Leilah Fluctus. The origin and the nature of the bright material is unknown: is it linked to cryovolcanic events, liquified materials resulting from a meteoritic impact or quakes, or meteorologic phenomena ( rainfall ) ? The nature of the bright material might be linked to cobbles, roughly fist-sized rocks deposited by the flows. The data suggest, anyway, that erosion plays a key role in the area, especially via tectonic ( faulting ) and fluvial processes as inferred from the topographic data of Ganesa Macula and Leilah Fluctus.

Image source: NASA / JPL / USGS

This set of radar images reveals topographic features of the Belet region on Saturn's largest moon. The lower view is the same view as the black and white view with color coding to reveal elevations, as shown by the color bar at left. The black and white portion at the top corresponds to a view taken by the Cassini spacecraft during the T8 flyby on October 28, 2005. The area is centered near 9 degrees south latitude, 290 degrees west longitude, and is approximately 450 kilometers ( 280 miles ) across. The maps are represented in equirectangular projection with north to the top.
Elevations data provided by the color view were obtained thanks to different views of the same region captured by the radar mapper. As a result, the Cassini scientists have produced stereo views of the equatorial region, Belet, which enables them to present 3D images of the landscape. The portions used for mapping were captured during flybys on October 28, 2005 ( T8 ) and December 12, 2006 ( T21 ).
As the color map shows, from the lowest land, appearing in purple, to the highest terrain, appearing in red, the total range of relief is about 700 meters ( about 2,300 feet ). The zero elevation level represents a distance of 2,575 kilometers ( 1,600 miles ) from the center of the moon, which corresponds, approximately, to the mean radius of the satellite. The Belet region unveils the wide-spread pattern of linear and parallel dunes. The equatorial band turns out to be dominated by Sand Seas and Seif dunes or longitudinal dune fileds.
The topographic map unveils large dune structures whose height ranges from 100 to 150 meters ( 300 to 500 feet ). This result is consistent with previous estimates. The light streaks of the dunes generally correspond to their crest or peak. It seems that only around 200 meters ( 600 feet ) of relief is enough to stop or divert the dunes. The elevated terrains represented by green, yellow or red patches, appear, mostly, to be dune-free areas and they act as obstacles for the dunes.

Image source: NASA / JPL / USGS

In this mosaic of images, the southern boundary of the optically bright region Xanadu is represented. The radar swath was obtained by the radar mapper of the Cassini spacecraft on February 22, 2008. The broad radar arc is approximately 3,450 kilometers long ( around 2,145 miles ) and the topography scanned extends from 28 degrees south latitude, 150 degrees west longitude to 28 degrees south latitude, 65 degrees west longitude. The width of the radar portion , from top to bottom, ranges from 150 to 530 kilometers ( approximately 95 to 330 miles ). Radar illumination comes from the south. On the upper left of the mosaic, the blue and grey inset is a global map of Saturn's largest moon which shows the location of this radar swath.
Xanadu appears relatively bright in both infrared and radar wavelengths. It's likely that the area is composed of mixtures of water ice, ammonia ice or frozen carbon dioxide. Xanadu was first believed to be an elevated terrain but Cassini near-infrared and radar data have revealed that the region seems relatively flat, although it has probably been both compressed and extended by potentially strong tectonic forces.
The radar swath shows clear landscape contrasts with a darker and more absorbing western part. The western area seems to be dominated by dark plains which are relatively common on Titan's surface. In that area, a few cavities or round features can be spotted: are they remnants of meteoritic impacts or dried-up lakes ? From the middle of the swath to the east or the right, bright patches appear: they correspond to mountainous terrain typical of Xanadu. Some bright and sinuous channels can be identified: are they the outcome of cryovolcanic phenomena, meteorological phenomena or meteor impacts ?
One of the most intriguing landscape features of Titan dominates the eastern part of Xanadu, at the extreme right portion of the swath: this is the landscape feature called Hotei Arcus which shows bright lobate features and radar-bright channels. The bright channels originating in the bright arc of Hotei Arcus are oriented northward. The bright arc seems to be dominated by mountains or hills. And like most mountains, they appear to have driven the bright channels to the north. Some scientists advance the idea of cryovolcanic flows of frozen ammonia-water slush. Marc Lafferre argues that Hotei Arcus might be the outcome of a meteoritic impact which would have crashed with a low angle from a north-south direction generating a bright arc of mountain ranges. The bright channels, observed, would have transported the molten material resulting from the impact northward.

Image source: NASA, JPL

This view of Titan's disk which represents the Saturn-facing hemisphere of the moon was captured by the narrow-angle camera of the Cassini probe on January 30, 2009. North is up and inclined 34 degrees to the left. The image was obtained at a distance of about 2.3 million kilometers ( 1.4 million miles ) from Titan, using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The image was captured with a low phase angle: the camera acquired this view with a Sun-Titan-spacecraft, or phase, angle of only 26 degrees. As a result, nearly the entire disk of Saturn's largest moon is illuminated by the Sun, with the star appearing behind the Cassini spacecraft.
One can clearly notice the dark equatorial regions of the moon with, from the left to the right, the eastern part of Fensal and Aztlan, the Senkyo region and to the east, the western part of Belet. One can also mention the bright area called Tsegihi, in the south of the equator, below Aztlan and Senkyo.
The most intriguing feature in this view appears to be the relatively dark patch in the north polar region, called Kraken Mare. There is a high probability that this landscape feature is the largest pool of liquid on Titan. This assumption is, mainly, based on radar data.

Image source: NASA, JPL, Space Science Institute

This updated map of Saturn's largest moon Titan was generated using infrared or near-infrared views captured by the imaging science subsystem ( ISS ) aboard the Cassini spacecraft. The views were obtained using a spectral filter centered at 938 nanometers. The global digital map is an equidistant projection and has a scale of 4 kilometers ( 2.5 miles ) per pixel. The map is still incomplete and the actual resolution is better near the center and edges of the map. The worst coverage turns out to be on the leading hemisphere centered around 120 degrees west longitude.
The coverage of Titan's north polar region is incomplete because the area has been in the winter season for several years. However, northern vernal equinox will occur in August 2009 which implies that the north pole comes out of shadow and that it will turn to summer very soon.
The near infrared views enable scientists to pierce through the opaque and hazy atmosphere of Titan and to discern landscape features via brightness variations or variations in albedo across the surface. As the atmosphere of the moon scatters light, no topographic shading is observed in the images presented here. The map is based on the hypothesis that the moon is spherical until a control network is created for Titan.
The map clearly shows that the equatorial latitudes present a relatively low reflectivity or albedo. Radar data have shown that they are dominated by longitudinal dunes similar to "Seif dunes", generally oriented from the west to the east. The northern and southern latitudes appear to harbor lakes or seas of hydrocarbons as radar images suggest. In this map, one can, notably, see the lower part of Kraken Mare at about 60 degrees north latitude and 320 degrees west longitude, a landscape feature which is likely to be the largest body of liquid on Titan.

Image source: NASA, JPL

This radar view of Titan was obtained by the radar mapper of the Cassini probe during the flyby of December 21, 2008. The portion shown is centered near 19.2 degrees south and 257.4 degrees west. The covered area is 220 kilometers long ( 137 miles ) and 170 kilometers wide ( 106 miles ) and north is approximately found toward the upper part of the image. The radar illumination comes from the right and the incidence angle is roughly 25 degrees.
This geographic portion which is part of the Belet region shows topographic characteristics which appear to be common in the dark equatorial areas of Titan: a multitude of linear, parallel or longitudinal grooves, channels or dunes dominate the landscape. Those particular features were first identified in radar images captured during the T3 flyby on February 15, 2005 toward the north-east of the bright Xanadu. Scientists called these features "cat scratches".
Those "Cat Scratches" have been identified as dune fields which appear to be generated by prevailing winds which tend to blow from the west to the east. In this view of the southern boundary of the dark equatorial region Belet, the dunes are generated by winds, which locally come from the west and north-west and blow toward the east. The dunes are reminiscent of Seif dunes on Earth.
One can clearly notice the action of winds and dunes on topographic obstacles which deflect the dominating movement of the dunes. In the upper part of the view, the radar-bright patches are identified as obstacles rising above the surrounding terrain and their shape is influenced by the winds and the dunes.
In the lower part of the portion, a plateau or a featureless plain seems to be present: no dunes take shape in that area. It is probably made up of a different kind of material and it is not sandy or the sand is not abundant enough to generate the typical dune fields observed above.

Image source: NASA, JPL

This global map of Saturn's largest moon, Titan, reveals the orientation of prevailing winds indicated by white arrows. The base map, appearing in false color, uses infrared or near-infrared views obtained from the imaging science subsystem ( ISS ) aboard the Cassini spacecraft. The direction or the orientation of dominating winds was inferred from data captured by the Cassini radar mapper and collected over a four-year period.
Radar images have revealed that the equatorial dark areas, which are particularly absorbing in the infrared spectrum, are dominated by longitudinal dunes, generally oriented west-east. The white arrows show the presumed direction of the winds, based on the radar observations. It's likely that the winds are not completely uni-directional. As a result, the shape and the orientation of the dunes, reminiscent of Seif dunes on Earth, is probably the outcome of the net effect of winds which can blow, occasionally or permanently, from different directions and combine to draw the landscape patterns observed.
Some dark areas have not yet been examined by the radar mapper. It's likely that they are also dominated by longitudinal dunes. This map clearly unveils global wind patterns in the equatorial region, with prevailing winds apparently blowing from the west to the east which contradicts some previous models of Titan's climate.

Image source: NASA, JPL

This infrared view of Titan was acquired from the Cassini probe with the ISS narrow-angle camera on January 2, 2009 using a spectral filter sensitive to wavelengths of near-infrared light centered at 938 nanometers. The image was captured at a distance of about 1.7 million kilometers or 1.1 million miles from Titan, and at a Sun-Titan-spacecraft, or phase, angle of 54 degrees. North is up and inclined at an angle of 24 degrees to the right. The shot looks toward the Saturn-facing hemisphere of Saturn's largest moon.
One can clearly notice the "Lying H", the dark-looking area extending along the equator. The upper band of the dark area, lying above the equator is Fensal, named after a magnificient mansion in Norse mythology. The lower band of the dark area, lying beneath the equator, is Aztlan, a region named after the mythical Aztec homeland. The two dark bands are separated by a bright patch named Quivira.
In the eastern part of Fensal, one can spot a bright patch encircling a dark, circular landscape feature. The bright patch, named Bazaruto Facula, is approximately 215 kilometers wide or 134 miles wide. The dark, round area, named Sinlap, inside this bright patch, appears to be a crater. It is about 80 kilometers or 50 miles in diameter.

Image source: NASA, JPL

These three updated maps of Saturn's largest moon, Titan, released on January 29, 2009 were generated from views dating from April 2004 through August 2008. They incorporate data from the Cassini Imaging Science Subsystem. The map in the upper part of the mosaic, which covers the whole globe of Titan, is a simple cylindrical projection. The circular maps in the lower part of the mosaic focus on Titan's polar regions: the incomplete map at bottom left is a north polar projection unveiling landscape or atmospheric features ranging from 55 degrees north latitude to 90 degrees north latitude. The lower right map which is a south polar projection covers the portion ranging from 55 degrees south latitude to 90 degrees south latitude. The resolution of landscape or atmospheric features in the maps varies from a few meters to a few tens of kilometers per pixel. In the top map, the northern latitudes are not entirely covered due to atmospheric effects which complicate integration of data from the "arctic region". The polar maps, on the other hand, correctly incorporate the polar views gathered up to now. The maps notably include Cassini's August 2008 imaging of Titan's northern hemisphere.
Brightness variations yield some information on the nature of the landscape or the topography because they are linked to differences in surface albedo rather than topographic shading. Dark areas will be less absorbing in that spectrum than bright areas: a potential lake or sea is likely to appear uniformly dark in those infrared maps while a potential ice shell should appear very bright. The dark equatorial regions, Senkyo, Belet, Shangri-La and Fensal Aztlan turn out to be mostly dry, often dominated by dune fields. However, the Huygens probe revealed on January 14, 2005 the presence of drainage channels on Adiri hills which implies that rainfall occurs.
The polar maps show a pleiad of potential lakes or seas surrounded by red or blue lines: blue outlines reveal features that changed between observations carried out one year apart. This may reveal new lakes appearing during tropical-like storms. The lakes are likely composed of liquid hydrocarbons such as ethane and methane. The radar data as well as the Visual and Infrared Mapping Spectrometer ( VIMS ) data strongly suggest the presence of bodies of liquid and Kraken Mare appears to be the largest pool of liquid in the north polar region while Ontario Lacus seems to be the largest sea in the south polar region.

Image source: NASA, JPL

These mosaics of infrared images show Titan's south polar region at two different times. The images were obtained in infrared light at a wavelength of 938 nanometers. The views have been oriented with the south pole in the center ( black cross ) and the 0 degree meridian toward the top. The upper left image was captured on July 3, 2004. The bottom left view is the same image with names, landmarks and descriptions of the main topographic or atmospheric features. The right images ( unlabeled at top and labeled at bottom ) were acquired on June 6, 2005.
The images, captured approximately one year apart, clearly reveal significant changes in landscape and atmospheric features: the bright patches identified as cloud formations appear in different locations between the two periods which implies that they are particularly dynamic as on Earth. Has there been precipitations ? Have they migrated northward ? The different observations of the south pole and mid-latitudes suggest that clouds change rapidly on timescales of hours and appear in different locations from day to day. Observers on Earth as well as Cassini's imaging science subsystem have had the opportunity to regularly spot the south polar cloud formations between the two Cassini observations above. The clouds turn out to appear in the troposphere that is Titan's lower atmosphere.
The south polar region seems to show a myriad of lakes as dark landscape features suggest. In the 2005 observation, an area, circled in the mosaics, which appeared relatively uniform in the 2004 observation is covered by dark patches: those low-albedo patches which, in other words, have a low reflectivity in the selected infrared spectrum are likely lakes filled by seasonal rains of liquid hydrocarbons such as ethane or methane. The new lakes or dark areas may originate from an exotic storm generating significant quantities of rain.
The giant lake,Ontario Lacus, as well as the dark patch Mezzoramia show changes in brightness between the two infrared observations: it is linked to differences in illumination between the two Cassini observations. The questions regarding the development of the lakes and their evaporation process don't lead to clear answers yet but it seems that the hydrocarbons show a great volatility.

Image source: NASA, JPL

This infrared view of Titan was obtained with the Cassini probe narrow-angle camera on December 12, 2008 using a spectral filter sensitive to wavelengths of infrared light centered at 938 nanometers. The image was captured at a distance of about 2.361 million kilometers ( 1.467 million miles ) from Saturn's largest moon and at a Sun-Titan-spacecraft, or phase, angle of 35 degrees.
The hemisphere shown by the Cassini orbiter corresponds to the Saturn-facing hemisphere, the hemisphere which always faces the ringed planet. Thus, the lowland dunes of Shangri-La and the higher terrains of Adiri, visited by the Huygens probe, are not visible, here: they are located on the opposite side of Titan. The image unveils the dark regions of Senkyo and Aaru. Senkyo is the dark equatorial region to the east of the view and Aaru appears above Senkyo. To the west, one can notice the eastern part of the dark regions Fensal and Aztlan. The region Belet which lies to the east of Senkyo doesn't appear in this view. North is up in this image.
Aaru's name derives from the Egyptian fields of Aaru which were paradise for the god Osiris. Senkyo's name derives from the Japanese ideal realm of aloofness and serenity, freedom from wordly cares and death.

Image source: NASA, JPL