Xplanet renders planetary and solar system images. It can be used to create
computer wallpapers or single images. Xplanet can show city names, overlay 
cloud maps or display which regions of Earth are day or night.  Xplanet can
be used to produce projected maps based on several projections, such as 
mollweide, which show the whole earth at once, or mercator, which is 
rectangular and is suitable for filling the screen.

See /usr/share/xplanet for maps, config files, scripts, and so on.