Fakhri sextant
An arc in the rock.
Hasan Tohirov — CC BY-SA 4.0 · Jean Housen — CC BY-SA 4.0 · ほっきー — CC0 · Adam Harangozó — CC BY-SA 4.0 · ShHamrayev — CC BY-SA 4.0 · BERNARDO RUZICKA — CC BY-SA 4.0 · Jean Housen — CC BY-SA 4.0 · Jean Housen — CC BY-SA 4.0
An astronomical observatory built in the 1420s by Ulugh Beg, Timur's grandson and ruler of Samarkand, himself a mathematician and astronomer. It was the last of the great medieval Islamic schools of astronomy, and scholars including Jamshid al-Kashi, Ali Qushji and Ulugh Beg himself worked here. Here Ulugh Beg measured the solar year at 365 days, 5 hours, 49 minutes and 15 seconds, only 25 seconds off, more accurate than Copernicus about a century later. His astronomical tables were translated into many languages. The observatory was destroyed in 1449 and its remains rediscovered in 1908. Today visitors see the surviving part of the giant Fakhri sextant, an arc cut into the rock below ground, and next to it a small museum of manuscripts, instruments and the observatory's history, with a statue of Ulugh Beg. Entry is by ticket, per visitor guides. It is about three kilometres from the Registan, easily reached by taxi.
An arc in the rock.
25 seconds off.
Manuscripts and tools.
On a hill in northeast Samarkand
It measured the solar year to within 25 seconds and produced astronomical tables translated into many languages, more accurate than Copernicus a century later.