The ancient astrolabe where Jewish and Islamic science mix

AImost exactly a year ago, Federica Gigante was preparing a lecture and searching the internet for a portrait of the 17th-century Italian nobleman and collector Ludovico Moscardo when an altogether different image caught her eye.

- SAM JONES

The historian's gaze snagged on a photo of a metal disc with a ring at the top that was kept in the same Verona museum as Moscardo's picture.

Gigante immediately knew she was looking at an astrolabe - an instrument used to map the stars and tell the time - and an extraordinary one at that.

But she would have no idea just how rare and special it was until she travelled to the Fondazione Museo Miniscalchi Erizzo three months later and watched the light stream through one of the museum's windows to illuminate the instrument's brass features.

"I saw it was a lot more ancient than they'd realised," she said. "But at that point, I had no idea it had Hebrew on it. It was only when we took it to a side room and I started to analyse it - by chance I was sitting by a window and the raking light came in - that I started to see these scratches. They were very strange because they weren't the scratches you'd expect from use. I thought maybe I was just a bit too tired, but more kept coming out."

Gigante, a research associate at Cambridge University's history faculty and a former curator of Islamic scientific instruments at Oxford University's History of Science Museum, had stumbled on a remarkable astrolabe that has passed through Muslim, Jewish and Christian hands in Spain, north Africa and Italy in the 10 centuries since it was constructed in Andalucía.