Ulug Bek, grandson of Amir Temur, found a place in history as one of the greatest sienctists in the historyof the world. He first founded a university for the study of theology and science, the Ulug Bek Medresse in the Registan Square, one of the world's most beautiful monuments, where the leading mathematical scientists researched and taught. He then went on to establish the largest and best equipped astronomical observatory of the Middle Ages. Samarkand became an important scientific center for much of the world, with its scholars influencing scientific thinking and work in many countries

The observatory was built in the form of a cylinder on 3 levels. 30.4 m high, 46.4 m in diameter. Sunk deep into the ground for stability in this earthquake prone area, lay the monumental Fakhri Sextant made of marble with the exceptional radius of 40.21m to improve scientific accuracy, since telescopes were not available.

The sextant was found during archaeological excavations and appeared to remain well-preserved. It is an arc of one sixth of a circle (60o). The arc of the sextant is limited by two barriers tiled with marble. The sextant is precisely oriented towards the meridian. Points and digits are carved on the marble surface, indicating degrees of the circle. Each degree corresponds to an interval of 70 cm. Along the barriers, brick stairways lead under ground.

Azimuthal observations were carried out on the horizontal circle at the top of the building, with other instruments that have not been preserved. In the observatory, there were also small-sized measuring instruments: a sundial, a sidereal clock, astrolabes, armillary spheres, and others.

2 of the most renouned scientists of the time, invited by Ulug Beg to Samarkand, were Jamshid al-Kashi's and Qadi Zada with Al Kashi becoming the eminent scientist and closest collaborator of Ulug Beg. At the Medresse, scientific problems andvarious approaches were freely discussed.

Ulug Beg and his team of 60 scientists, scolars and students worked on a number of projects. Their primary target was to revise the findings of their astrological predecessor Ptolemaeus from II century and Al Sufi from X century. In 1437, the Sij i Sultani calendar of stars was completed, comprising 992 fixed stars and detailed tables of the longitudinal motion of the sun, moon, and the planets, longitudinal and latitudinal parallaxes for certain geographical latitudes,eclipses, of the visibility of the moon. Translated into several languages, the Sij i Sultani became the reference work for the next 200 years and established Ulug Bek among the world's greatest astronomers.

In 1437 the scientists around Ulug Bek determined the length of the sidereal year as 365.2570370 days.

The base of Astronomical studies are higher mathematics trigonometry and spherical geometry and Al-Kashi set new, highly praised teaching standards with his work The Key to Arithmetic in 1427, prepared students for the scientific endeavour at the Medresse.

The complex architectural structures of the splendid buildings of Medieval Central Asia also required knowledge of higher mathematics. For example the measurement of the muqarnas refers to a stalactyte type of decoration made of 3-dimensional polygons to hide the edges and joints in mosques and palaces with plane or curved surfaces. Al-Kashi used decimal fractions in calculating their total surface.

Although Al Kashi did not invent decimal fractions per se, he was influential in contributing to the usage of decimal fractions no longer for approaching algebraic numbers, but for real numbers such as Pi.

The groupe's Treatise on the Circumference in July 1424 was an achievement far beyond anything which had been obtained before, either by the ancient Greeks or by the Chinese.

An treatise by Qadi Zada was on the problem of facing Mecca, making invaluable contributions to determining the exact direction of the holiest place of Islam's holiest place

All these discoveries were long unknown in Europe and were studied only in the IIX and XX centuries by historians of science
In 1964, the Ulug Bek Memorial Museum was opened by the observatory, exhibiting items that show the life and scientific work of the great scientist such as ceramics, coins, metalware, architectural drawings of Chil-Sutun, Ulug Bek's palace, and his Medresse.
On the second level of the exhibition you find exhibits about Ulugbek's teachers and associates, as well as models of small-sized astronomical instruments, work data of Samarkand astronomers in comparison with the data by modern scientists. Replicas of XVII century engravings show Ulug Bek's place among astronomers of the world.

The exhibition is crowned with a dome depicting "Ulug Bek's celestial map".