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Jovian Satellites
Io
-Mosaics
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Images

Jupiter Satellites - Io

Merged Products

To present more information-rich views of Io, the global color derived from the Galileo color images was superimposed on the more detailed, higher resolution monochrome mosaics. The procedure adopted was to calculate color ratio images from the Ga lileo data and apply them to the monochrome mosaics, requiring that the color ratios of the composite images match the color ratios of the Galileo data. The Galileo SSI camera's silicon CCD was sensitive to longer wavelengths than the vidicon cameras of Voyager, so that dist inctions between red and yellow hues can be more easily discerned. However, this approach suffers from an obvious disadvantage in areas where the surface appearance changed dramatically during the 20+ year interval between the Voyager and Galileo eras, for example near Kaneh ekili.

Galileo/Voyager Merged Product

Galileo Color Mosaic
Latitude range: -90 to 90
Longitude range: 0 to 360
Map Scale: 1.0 kilometers/pixel
Larger image for viewing: 1 MB
Full size image for downloading: 152 MB
Compressed ISIS cub file: 67 MB

Galileo Merged Product

Merged Product
Latitude range: -90 to 90
Longitude range: 0 to 360
Map Scale: 1.0 kilometers/pixel
Larger image for viewing: 49 KB
Full size image for downloading: 152 MB
Compressed ISIS cub file: 63 MB

Galileo High Resolution Mosaic

The best quality global monitoring images taken by the Galileo imaging system at spatial resolutions up to 1 km/pixel have been assembled here to depict the global and regional morphology of Io. This mosaic is made up of 32 monochrome images taken at various phase angles and local times of day, so care must be taken to note the solar illumination direction when deciding whether topographic features display positive or negative relief. In general, the illumination is from the west over longitudes 0 to 270 W, and from the east over longitudes 270 W to 360 W. The images were empirically adjusted in brightness and contrast to match one another in areas of overlap. Most of the images were taken in the clear filter, but green and 756 nm filter images were substituted when they were more detailed than other available images. Image resolutions range from 1.3 to 10 km/pixel along the equator, with the poorest coverage on the Jupiter-facing side of Io.

Galileo High Resolution Mosaic
Latitude range: -90 to 90
Longitude range: 0 to 360
Map Scale: 1.0 kilometers/pixel
Larger image for viewing: 318 KB
Full size image for downloading: 24 MB
Compressed ISIS cub file: 17 MB

Galileo/Voyager High Resolution Mosaic

Although the subjovian hemisphere of Io was poorly seen by Galileo, superbly detailed Voyager 1 images cover longitudes from 240?W to 40?W and the nearby southern latitudes. A global mosaic of the best resolution images from both Galileo and Voyager 1 is shown here that includes 51 Voyager 1 images with spatial resolutions sometimes exceeding the 1 km/pixel scale of the final mosaic. While most of these images neatly overlie the Galileo coverage, the Voyager 1 images of regions west of 0? longitude appear displaced from the positions predicted from the control net derived from the solution of the combined Galileo and Voyager data set. We suspect that the discrepancy arises from regional topography west of the sub-Jupiter point, and have adjusted the positions of the Voyager 1 images (all acquired near the limb of Io) to match the best-fit geometry of Archinal et al. (2001). Solar illumination of these longitudes was from the east during the Voyager 1 flyby. Image resolutions range from 1.0 to 10 km/pixel along the equator, with the poorest coverage centered on longitude 50 W.

Galileo/Voyager High Resolution Mosaic
Latitude range: -90 to 90
Longitude range: 0 to 360
Map Scale: 1.0 kilometers/pixel
Larger image for viewing: 326 KB
Full size image for downloading: 25 MB
Compressed ISIS cub file: 18 MB

Galileo Color Mosaic

This Galileo global false color mosaic was constructed from low phase angle violet, green, and near-infrared (756 nanometer) images from orbits G2, E6, C9, and C21. The images were calibrated using the best end-of-mission calibration information, corrected empirically for limb-darkening, and map projected using the camera-pointing corrections of Archinal et al. (2001). The coregistered color images were next hand-edited to remove topographic shadows and pixels too near the limb, and mosaicked using a numerical procedure (Soderblom et al., 1978) that reduces the mismatch at the seams. This mosaic represents our best understanding of Io's color as pictured during the Galileo Mission. The true colors that would be visible to the eye are similar but much more muted than shown here. The spatial resolution of the mosaic ranges from 1.3 to 21 km/pixel at the equator, with the poorest resolution on the Jupiter-facing hemisphere of Io.
Merged Product
Latitude range: -90 to 90
Longitude range: 0 to 360
Map Scale: 1.0 kilometers/pixel
Larger image for viewing: 33 KB
Full size image for downloading: 142 MB
Compressed ISIS cub file: 42 MB

Ancillary Data

Galileo monochrome

CUB files PDF files

Galileo color

CUB files PDF files

Voyager + Galileo

CUB files PDF files

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