Bayrām Ibn Ilyās. Sundial, Compass and Quibla Indicator, Istanbul, ca. 1583.
The 'Weldon' Pocket Compass and Sundial.
Sundial, Compass and Quibla Indicator by Bayrām Ibn Ilyās (1582-1583) A Qibla compass or qiblah compass (sometimes also called qibla/qiblah indicator) is a modified compass used by Muslims to indicate the direction to face to perform ritual prayers. In Islam, this direction is called qibla, and points towards the city of Mecca and specifically to the Ka'abah. While the compass, like any other compass, points north, the direction of prayer is indicated by marks on the perimeter of the dial, corresponding to different cities. To determine the proper direction, one has to know with some precision both the longitude and latitude of one's own location and those of Mecca, the city toward which one must face. The outermost circle along the rim is divided into 72 sectors that give the names of cities and regions in the Islamic World, all written in black with the exception of Qustantinīa (Istanbul) which is written in red. Each sector contains at least two, often more names, separated from each other by gold dots. Presumably, one finds the city one wants and determines the direction of Mecca from the markings around the compass. [British Museum, London]