Depiction of Mecca by Louis-Nicolas de Lespinasse, 1787

Commentary
Depiction of Mecca by Louis-Nicolas de Lespinasse, 1787

One of the many functions of the astrolabe in the Islamic world was to find the sacred direction towards the Ka’aba in Mecca, known as the qibla. Most Islamic astronomical handbooks compiled during the millennium beginning 750 AD contain a chapter on the determination of the qibla, in which the problem is solved via some trigonometric function involving the longitude and latitude of Mecca and the local coordinates.

Commentary. Philipp Nothaft (May-June 2019)