Horizontal quadrant with compass

The arcs of hyperbola of this quadrant represent the surplus of the sun in the solstices and the straight line represent its course in the equinoxes. It would be used by suspending three threads located at the base of the quadrant at equidistant points. It contains a circle in which the magnetite was placed, so that the quadrant was oriented towards the magnetic north. Ibn a-Raqqam (1315) was a Maghrebi astronomer of probably Murcian ancestry who spent most of his life at the court of Nasrid King Muhammad II. He wrote a treatise that developed the construction of all type of sundials.