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|Fig. 1. — PERSIAN ASTROLABE (c.1712) INSCRIBED IN ARABIC.|
|Front, showing the Rete or Spider, a network of star pointers. Beneath the Rete, in a hollow, are four thin brass discs, called Tables or Climates, engraved with projections of the sphere for different latitudes.||Back, showing graduations, parallelogram for measuring heights, and other tables, together with the Rule with sights (A) held by a moveable pin (B), known as the Horse or Wedge.|