Ancient Stargazing Marvel Seeks $1.1 Million at Auction

This exceptionally rare, gilt brass astrolabe helped orient travelers toward Mecca.

Well before sextants were invented, people across the medieval world used astrolabes to calculate the altitude of a star above the horizon. (Christopher Columbus apparently carried one when he crossed the Atlantic.) It had both practical and religious applications: Muslims used the thin, disclike objects to determine the direction of Mecca. This particular gilt-brass example was probably used for the latter purpose. The letters are written in Kufic, a type of Arab script, and the exquisite, intricate case bears the signature of a Muslim craftsman from northern Spain. The work is expected to sell for £600,000 to £800,000 ($835,000 to $1.1 million) at a Sotheby’s London auction on March 31.


• Not all astrolabes were metal—it’s just that most of the paper ones didn’t survive. A 19th century example that did is available at Daniel Crouch Rare Books for £35,000.

• Astrolabes don’t have to cost as much as a mansion. In the same sale, Sotheby’s has listed a slightly less rare Persian astrolabe that dates from about 1660. It carries a high estimate of £150,000.