Islamic horary quadrant, Persian, 1701-1800

Wooden horary quadrant (25-cm radius) with painted scales and leather case, Islamic script, unsigned, Persia, 1701-1800.

This unsigned Islamic horary quadrant was made in Persia (Iran) during the eighteenth century. Made of wood the quadrant has hand drawn painted scales and inscriptions. The horary quadrant was used for finding local time by sighting either the Sun or a bright star at night. Held vertically, a measurement could be taken from the position on the scale of a moveable bead on the thread of the plumb bob of the instrument. The horary quadrant was derived from the astrolabe and first appeared during the Medieval Period. Like its predecessor, it includes a two-dimensional depiction of a celestial sphere that is reduced to a quarter.