Fig. 23. Visual Comparison of Topography on Ganymede and Callisto.

Voyager 1 images of the terminator regions of Ganymede (left) and Callisto (right), qualitatively showing the difference in surface roughness. Note the greater frequency of highlighted sun-facing slopes on Callisto, indicating a rougher surface at a kilometer scale. Both images have very similar resolution, geometry, and processing (simple linear stretch). Distance across each image is about 1000 km. Images are:
Ganymede: 16405.42, range = 133,000 km, solar phase angle = 81^o.
Callisto: 16425.18, range = 125,000 km, solar phase angle = 83^o.
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