細節
A SAFAVID BRASS ASTROLABE
IRAN, SECOND HALF 17TH CENTURY
The brass mater with throne and suspension shackle above, the rim graduated degree scale, with three plates engraved on both sides each bearing stereographic projections except for one marked with hours for prayer, all with naskh inscriptions, altitude circles every six degrees, azimuth arcs every ten degrees, the rete with 25 named star pointers, the reverse of the mater with an empty top left quadrant, a quadrant with ten projections, calendarical scales to lower half, gazetteer to the back plate of the mater, the original graduated alidade with two holed sighting vanes, the edge with further naskh inscription
3¼in. (8.3cm.) diam.; 4 3/8in. (10.6cm.) high (excluding shackle)