In the 15th century, Ulugh Beg, the ruler of the Timurid Empire, transformed Samarkand into a major scientific center of the East. He invited leading scholars to the city and built an observatory where they calculated the length of the sidereal year and the tilt of the Earth’s axis with astonishing accuracy.

Ulugh Beg Observatory is located on the northeastern outskirts of historic Samarkand, near the ancient settlement of Afrasiyab. Only part of the original structure has survived. But the ruins still give visitors an idea of the observatory’s scale and the remarkable level of scientific knowledge achieved in medieval Central Asia.

A Ruler Devoted to Science

Unlike many medieval rulers, Ulugh Beg is known not for military campaigns but for his passion for science, especially mathematics and astronomy.

Between 1417 and 1420, the Ulugh Beg Madrasa was built on Registan Square. This institution taught not only religious disciplines but also mathematics and other exact sciences. A few years later, Ulugh Beg decided to establish an observatory.

The observatory was a three-story cylindrical building about 30 meters (100 ft) tall, roughly the height of a ten-story apartment building. Inside was a massive sextant measuring about 40 meters (130 ft) in diameter. It was used to determine the altitude of celestial bodies above the horizon.

The observations made in Samarkand were remarkably precise for their time. European astronomers reached a comparable level of accuracy only two centuries later.

The scholars working in the observatory also calculated the length of the year with great precision. Some of their calculations differed from modern measurements by only a few seconds. All these observations were compiled in the Zij-i-Sultani, a groundbreaking astronomical work that mapped more than a thousand stars and recorded the movements of planets and other celestial bodies.

Destruction and Oblivion

After Ulugh Beg’s death in 1449, the observatory continued to operate for another twenty years before falling into ruin.

Over time, local residents dismantled the building. The remains of the giant sextant were gradually buried beneath layers of earth. For several centuries, the exact location of the observatory was forgotten.

In 1908, archaeologist Vasily Vyatkin found the remains of the sextant and the site of the former observatory was finally determined.

What Remains Today

Today, the underground section of the massive sextant is what is left of the observatory. An arched pavilion was built over the structure to protect it from the elements. Visitors are allowed to go inside.

Nearby, stands a museum that tells the story of Ulugh Beg’s life and the development of astronomy in Central Asia.

Vasily Vyatkin is buried near the observatory in recognition of his role in unearthing and preserving the site. A monument to Ulugh Beg also stands within the complex grounds.

Other tourist attractions near the observatory:

• Mausoleum of Prophet Daniel
• Samarkand History Museum
• Konigil Meros Paper Mill
• Shah-i-Zinda Ensemble
• Islam Karimov Mausoleum
• Siab Bazaar
• Bibi Khanym Mosque
• Registan