The astrolabe reached the peak of its popularity in the 16th century. The Spanish astronomer and mathematician Juan de Rojas presented to the European public the Orthographic Projection (1550). This projection was successfully applied in a new type of astrolabe that offered remarkable advantages over its predecessors because it could be used in any Northern latitude.
Traditional astrolabes required different plates for each Latitude, and this made them costly and awkward. Furthermore, though the instrument was flexible, it was not apt to solve a certain set of problems. Gemma's Astrolabum Catholicum had two faces: one of them correspondent to a common astrolabe, and the second one could be used in any Latitude by placing a magnetic compass at the throne. The Rojas' Astrolabe was named after Juan de Rojas y Sarmiento. However, he did not invent this type of instrument, nor was he the first to use orthographic projection, and he willingly acknowledged this.
This reproduction was made as faithful as possible to the original but, at the same time, updated and furnished with certain essential elements that make it useful in present times.