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Paris, France (ESA) May 16, 2005 As the large amount of data collected by the ESA Huygens probe during its descent onto Titan is being processed, new views of this fascinating world become available. The Descent Imager Spectral Radiometer (DISR) team have now produced the first complete 'stereographic' and 'gnomonic' mosaic images. Using special image projection techniques, the team combined a series of images captured by Huygens while rotating on its axis at an altitude of about 20 kilometres. The DISR on board Huygens took its series of photographs of the ever-approaching surface in sets of three, or 'triplets', as it dropped through Titan's atmosphere on 14 January this year. The images sent back to Earth partially overlap, due to the probe's rotation during the descent and due to the overlap between the fields of view of the different cameras. DISR scientists are studying these images for similarities, such as physical features common to more than one image, and are constructing 'mosaics', like jigsaw puzzles. There are many different ways of rendering three-dimensional objects into two dimensions. Different kinds of projections for maps or photographs are able to represent realistically things like size, areas, distances, and perspective. One particular kind of projection used for spheres in two dimensions (for example on some maps of Earth or the celestial sphere) is 'stereographic' projection. A 'gnomonic' projection (pictured) has also been produced, and this tends to make the surface appear as if it was flat. This type of projection is often found on maps used by navigators and aviators in determining the shortest distance between two points.
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