I chose an old Islamic astrolabe, for example, a Yemeni astrolabe from the 12th century, and drew by hand a somewhat simplified model of two parts of the instrument on paper. These two drawings I ...

I chose an old Islamic astrolabe, for example, a Yemeni astrolabe from the 12th century, and drew by hand a somewhat simplified model of two parts of the instrument on paper. These two drawings I ...

A computerized model of al-Khujandi's astrolabe, through which scientists can demonstrated how easily it could function as a kind of a rudimentary analogue. Credit: Wilfred de Graaf, Utrecht ...

The identification of an eleventh-century Islamic astrolabe bearing both Arabic and ... They provided a portable two-dimensional model of the universe fitting in their user's hand, enabling ...

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.