Bidspirit auction | AN INDO-PERSIAN ENGRAVED BRASS PLANISPHERIC

AN INDO-PERSIAN ENGRAVED BRASS PLANISPHERIC ASTROLABE, 19TH CENTURY. - A complete  Indo-Persian planispheric astrolabe constructed from engraved brass. The instrument consists of a thick-walled mater with a raised rim or limb, which is engraved with degree scales and Arabic Abjad numerals. The interior of the mater, known as the umbilicus, contains a detailed gazetteer listing various cities alongside their respective longitudes and latitudes. The ornate throne or kursi is of high profile, featuring pierced and engraved floral and foliate scrolls, and is fitted with a circular shackle and a large brass suspension ring. The instrument includes a complex openwork rete or ankabut, representing the celestial sphere. This component features flame-shaped pointers for specific stars and a circular ecliptic band engraved with the signs of the zodiac in Arabic script. Accompanying the rete are four removable brass plates or tympanums, each engraved on both sides with stereographic projections for eight different latitudes. The reverse side of the astrolabe is fitted with an alidade or sighting rule, secured by a central pin and a later modern slotted screw. The back is densely engraved with various astronomical scales, including a quadrant for sines and cosines, a graph for determining the sun altitude, and a central shadow square. The lower section of the shadow square contains an engraved maker's signature and date. The inscription in Naskh-style Arabic script reads Sana'ahu aqall al-ibad Muhammad followed by a partially illegible name and the Hijri date. H: Approximately 17.2cm