See Titan with infrared eyes

Credit: NASA / JPL-Caltech / Stéphane Le Mouélic, University of Nantes, Virginia Pasek, University of Arizona

These six infrared images of Saturn's moon Titan represent some of the clearest views and the most more transparent of the world. surface of the icy moon produced up to now. The views were created using 13 years of data acquired by the Visual and Infrared Mapping Spectrometer (VIMS) instrument aboard the NASA Cassini spacecraft. The images are the result of a focused effort to seamlessly combine data from the multitude of observations that VIMS has made in a wide variety of lighting and visualization conditions during the mission of Cassini

. ) exhibit a wide variation in the resolution of imaging and lighting conditions, resulting in obvious seams between different areas of the surface. With the seams now gone, this new collection of images is by far the best representation of how the Titan Globe might appear to the casual observer if it was not for the first time. misty atmosphere of the moon, and it will probably not be replaced for some time to come.

It is difficult to observe the surface of Titan in the visible region of the spectrum, because of the fog that surrounds the moon. This is mainly because small particles called aerosols in the upper atmosphere of Titan strongly scatter visible light. But the surface of Titan can be more easily imaged in some infrared "windows" – infrared wavelengths where diffusion and absorption of light are much lower. It is here that the VIMS instrument has excelled, separating the haze to get clear images of Titan's surface. (For comparison, Figure B shows Titan as it appears in visible light, just like PIA11603.)

Figure B. Credit: NASA / JPL-Caltech / Stéphane Le Mouélic, University of Nantes, Virginia Pasek University of Arizona

Making mosaics of Titan's VIMS images has always been a challenge as data has been obtained on many different flybys with observation geometries and conditions different atmospheres. One result is that very visible seams appear in mosaics that are quite difficult to eliminate for imaging researchers. But through painstaking and detailed analysis of the data, as well as the manual processing of the mosaics, the seams were mostly removed. This is an update of the work previously discussed in PIA20022.

Any color image is composed of three color channels: red, green, and blue. Each of the three color channels combined to create these views was produced using a ratio between the brightness of the Titan surface at two different wavelengths (1.59 / 1.27 microns [red] 2.03 / 1.27 microns [green] and 1.27 / 1.08 microns [blue]). This technique (called the "ratio-band" technique) reduces the prominence of the seams, while highlighting the subtle spectral variations of the materials on Titan's surface. For example, the equatorial dune fields of the moon appear here in a uniform brown color. There are also bluish and purplish areas that may have different compositions from other light areas, and may be enriched with ice water.

For a Titan map with latitudes, longitudes and labeled surface features, see PIA20713. is very clear from this unique set of images that Titan has a complex surface, sporting a myriad of geological features and composition units. The VIMS instrument pioneered future infrared instruments capable of imaging Titan at a much higher resolution, revealing features that were not detectable by any of Cassini's instruments.