AN OTTOMAN DAIRAT AL-MUADDIL (COMBINED SUNDIAL AND QIBLA FINDER), 17TH CENTURY

Diameter: approx. 24 cm.

The dairat al-mu’addil (Eng. equatorial circle) is an instrument with combines a sundial with a qibla indicator. It was invented by the 15th century astronomer and timekeeper at the al-Mu’ayyad mosque in Cairo, ‘Abd al-Aziz ibn Muhammad al-Wafa’i al-Miqati. It was later also described by other scholars, including the Turkish admiral Seydi Ali Reis, making the instrument very popular in Ottoman circles. [Maddison & Savage-Smith, p. 277].

Al-Wafa’i’s instrument seems to be inspired by another instrument, namely the “Sanduq al-Yawakit” or the “Jewel Box”, invented by an earlier, well-known, fourteenth century Syrian astronomer and timekeeper Ibn al-Shatir. [King, p.53]

TECHNICAL DESCRIPTION
The main disk of the instrument consists of a circular brass plate. The center of a disk features a magnetic compass. Around the magnetic compass is a wind-rose with the typical four quarters of the compass: shimal (north), junub (south), sharq (west), garb (east)], and in between alternatingly in Ottoman Turkish “orta” (intermediary winds) and “kerte” (rhumb lines). Around the circumference are marked the names and Qiblas of various localities. When the compass is used to align the instrument along the cardinal points, the Qibla can be read off simply by locating the name of the locality and reading of the direction of the Qibla.

The instrument also features a small sundial below the south point of the instrument equipped with a small gnomon. The various holes on the instrument are due to the missing parts such as four leveling screws and a graduated semi-circular arc which is hinged along the east-west line of the instrument. This arc can be inclined at any desired angle to the horizontal plane by means of the graduated scale in the plane of the meridian.

In this case this semi-circular arc and the graduated scale are missing along with other smaller parts.

DATE AND MAKER
The instrument is signed by the maker above the north point of the instrument in a cartouche as “ ’Amal Hasan Baba al-Duyuwi
1171” [1757/1758 AD], who seems to be unknown to literature.

LITERATURE
W. Brice, C. Imber and R. Lorch, The Dāi’re-yī Mu'addel of Seydī 'Alī Re'īs. Seminar of Early Islamic Science, Monograph no. 1, University of Manchester, July 1976
David A. King, “An Islamic Astronomical Instrument”, Journal for the History of Astronomy, Vol. 10 (1979), Issue 1, p 51-53
Francis Maddison & Emilie Savage-Smith, Science, Tools and Magic. Part One. Body and Spirit, Mapping the Universe. Nour Foundation, Oxford, 1997, p. 277-279