Frontispiece from the Blaeu world atlas, published in Amsterdam in 1647, showing a model representing the Earth and stars. The line passing through the Earth shows its axis of rotation. The multi- coloured band, marked with the signs of the zodiac, represents the ecliptic, the path the Sun traces out each year as projected against the fixed stars. The planets also move only in a narrow band centred on the ecliptic, and so appear always in one or other of the constellations of the zodiac.