Details
An Ottoman Turkish Quadrant,
undated, in wood and paper, lacquered, radii 6.1/8in. (15.6cm.) and 6¾in. (17.2cm.)
This is a typical astronomical quadrant from Ottoman Turkey, probably from the 19th-Century. This kind of instrument, with astrolabic markings for a specific latitude on one side and a trigonometric grid on the other, generally replaced the astrolabe as the favorite instrument of the Ottoman astronomers. This one is signed by [..?..], an unusual name unknown to the modern literature, and the astrolabic markings are for latitude 40°, probably intended for Bursa or Ankara. The markings are standard and include special curves for the first and second afternoon prayers, and for the time of fasting before daybreak during Ramadan (labelled imsâk). This last curve is drawn discontinuous below the horizon, part of the curve being folded over in order to fit on the quadrant. The two circular cartouches on this side and the five ovoid ones on the other side contain terse astronomical instructions on how to use this curve. Inside the main markings there is a universal horary quadrant and inside the semi-circular curve for midday there is an unusual inscription mâ phâ Allâh kân 'What God wills will be'. The back of the instrument bears a sexagesimal grid (base sixty) and various lines and curves, most of which provide different means of determining the altitude of the sun at the time of the afternoon prayer.
undated, in wood and paper, lacquered, radii 6.1/8in. (15.6cm.) and 6¾in. (17.2cm.)
This is a typical astronomical quadrant from Ottoman Turkey, probably from the 19th-Century. This kind of instrument, with astrolabic markings for a specific latitude on one side and a trigonometric grid on the other, generally replaced the astrolabe as the favorite instrument of the Ottoman astronomers. This one is signed by [..?..], an unusual name unknown to the modern literature, and the astrolabic markings are for latitude 40°, probably intended for Bursa or Ankara. The markings are standard and include special curves for the first and second afternoon prayers, and for the time of fasting before daybreak during Ramadan (labelled imsâk). This last curve is drawn discontinuous below the horizon, part of the curve being folded over in order to fit on the quadrant. The two circular cartouches on this side and the five ovoid ones on the other side contain terse astronomical instructions on how to use this curve. Inside the main markings there is a universal horary quadrant and inside the semi-circular curve for midday there is an unusual inscription mâ phâ Allâh kân 'What God wills will be'. The back of the instrument bears a sexagesimal grid (base sixty) and various lines and curves, most of which provide different means of determining the altitude of the sun at the time of the afternoon prayer.