Ottoman Turkish instrument made by İbrahim in 1866 of wood, richly decorated with flowers and leaves. Quadrants are used to measure the altitude of a celestial object – its angular distance above the horizon. The angle is measured by sighting the celestial object along the edge of the quadrant (quarter circle) and reading off the angle indicated by the plumb-line. On loan from the Bosphorus University Kandilli Observatory. L: 23.3 cm W: 22 cm H: 3 cm

This brass sextant with silver scale is signed “G. Santi et Cie à Marseille”. L: 30 cm W: 22 cm H: 9.8 cm