The Nova Compositio Astrolabii Particularis (found in only 4 manuscripts) describes the construction and use a universal astrolabe which could be used at a variety of latitudes without changing the plates. Unlike al-Zarqālī 's more famous universal astrolabe in which vertical halves the heavens were projected onto a plane through the poles, this one had both the northern and southern hemispheres projected onto a plane through the equator (which was also the limit of projection). There are no known surviving astrolabes based on this treatise. The use of such an astrolabe is very complicated, and since it is probable that most sophisticated users were not frequent travelers, they were more likely happier with the traditional (and simpler) stereographic planispheric astrolabe.