Io Galileo-SSI-1km survey collection

Although the subjovian hemisphere of Io was poorly seen by Galileo, superbly detailed Voyager 1 images cover longitudes from 240deg W to 40deg W and the nearby southern latitudes. A monochrome mosaic of the highest resolution images from both Galileo and Voyager 1 was assembled that includes 29 Voyager 1 images with spatial resolutions sometimes exceeding the 1 km/pixel scale of the final mosaic.

Because this mosaic is made up of images taken at various local times of day, 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 40 deg to 270 deg W, and from the east over longitudes 270 deg W to 40 deg W. Color information was later superimposed from Galileo low phase angle violet, green, and near-infrared (756 nanometer wavelength) images.