the zodiac was made during the lives of these men of myth and legend. it is a map written in the stars. hercules is leo, and cancer is hell, denoting death valley and the amazon.  think of it like this. an azimuthal equidistant map that is centered on rome, has the americas, asia, and australia in a kind of ring around it. they used major landmarks, like hercules settlement in america, to represent what would be under those stars at the time of the maps drawing, from the center point of rome.  take the angle your ship is facing against multiple constellations and overlay this in the azimuthal map, rotate the zodiac accordingly, and you will get your exact coordinates on a map.
Confederate