English: This is a star map for the celestial globe of Su Song (1020-1101), a Chinese scientist and mechanical engineer of the Song Dynasty (960-1279). It was first published in the year 1092, in Su's book known as the Xin Yi Xiang Fa Yao (Wade-Giles: Hsin Yi Hsiang Fa Yao). On this star map there are 14 xiu (lunar mansions) on Mercator's projection. The equator is represented by the horizontal straight line running through the star chart, while the ecliptic curves above it. Note the unequal breadth of the lunar mansions on the map.

Su Song's star maps had the hour circles between the xiu (lunar mansions) forming the astronomical meridians, with stars marked in quasi-orthomorphic cylindrical projection on each side of the equator, and thus was in accordance to their north polar distances. Not until the work of Gerard Mercator in 1569 was a celestial map of this projection created in the Western world (Needham, Volume 4, Part 3, 569).

This picture appears on page 277 of Joseph Needham's book Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth.