What I'm holding is a portable model of the heavens, in the shape of an exquisite, circular brass instrument that looks a bit like a large brass pocket watch, and it's called an astrolabe.

What I'm holding is a portable model of the heavens, in the shape of an exquisite, circular brass instrument that looks a bit like a large brass pocket watch, and it's called an astrolabe.

The identification of an eleventh-century Islamic astrolabe bearing both Arabic and Hebrew inscriptions makes it one of the oldest examples ever discovered and one of only a handful known in the ...