Lot 171: A MOROCCAN ENGRAVED BRASS SINE AND HORARY QUADRANT RUB AL-MUJAYYAB

An Islamic astronomical quadrant of the Rub al-Mujayyab, crafted from engraved brass. The instrument is constructed in a ninety-degree sector shape with a suspension ring mounted on a decorative floral-motif swivel shackle at the apex. Two integral sighting vanes, or pinnulae, are positioned along one of the straight radial edges. The obverse face serves as a horary quadrant, featuring a series of concentric arcs and curves designed to calculate solar altitude and the times for the afternoon prayers known as Asr. The outer curved edge is marked with a scale from 0 to 90 degrees using Abjad alphanumeric notation. The reverse face acts as a sine quadrant, or graphical calculator, containing a dense grid of horizontal and vertical lines for trigonometric functions. Superimposed arcs on this grid represent solar paths or universal latitude markers. 

L: 20cm