Ulugbek Observatory

Among the historical monuments of Samarkand, the observatory, built by Ulugbek in 1428-1429 on one of the hills of Samarkand, occupies a special place. According to Babur (Timurid and founder of the Mughal state in India), who personally saw the observatory, it was a three-story, beautifully tiled circular building with a diameter of more than 46 meters and a height of at least 30 meters. In the main hall there was a huge instrument for observing the Sun, Moon and other luminaries of the firmament. The observatory was a unique building for its time.

The observatory was based on a giant protractor (vertical circle) with a circumference of 40.212 meters and an arc length of 63 meters. The main instrument, the sextant, was oriented with amazing accuracy along the meridian line from south to north. This is evidenced by the verification definitions of modern astronomers T. N. Kastalsky and V. P. Shcheglov.

The size of the main instrument, its successful design, and the scientific knowledge of Ulugbek and his associates ensured the astounding accuracy of astronomical observations.

Ulugbek is credited with creating the Ziji-Guragan astronomical catalog, known as the Ulugbek Star Tables. A whole galaxy of major scientists worked on them for a long period and completed them by 1437. The work created at the Ulugbek Observatory was an outstanding contribution to the treasury of world astronomical science. "Everything that observation and experience have learned about the motion of the planets has been deposited in this book," wrote Ulugbek himself. This work summarizes the fundamentals of astronomical research conducted by scientists of the East. The accuracy of the observations of Samarkand astronomers is all the more amazing because they were conducted without the help of optical instruments, with the naked eye. The astronomical tables of Ulugbek contain the coordinates of 1018 stars. "Ziji-Guragan" has not lost its value in our days. The length of the sidereal year was calculated with amazing accuracy, which, according to Ulugbek's calculations, is 365 days, 6 hours, 10 minutes, and 8 seconds. The true length of the sidereal year, according to modern data, is 365 days, 6 hours, 9 minutes, 9.6 seconds. So the error is less than one minute.

Today, tourists can see the architectural and memorial complex, including the remains of a huge sextant, a small but interesting museum, and the Ulugbek monument.