Coordinate System
A crater named Anat provides the reference point for measuring longitude on Ganymede. By definition, Anat is at 128 degrees longitude.
Read more about this topic: Ganymede (moon)
Famous quotes containing the word system:
“Intimately concerned as we are with the system of Europe, it does not follow that we are therefore called upon to mix ourselves on every occasion, with a restless and meddling activity, in the concerns of the nations which surround us.”
—George Canning (1770–1827)