« I swear by the Sky and the Going in Night!
And, what let you know, who is the Going in Night?
Star All-pervading … »
(From Sura 86, Koran)
One of the essential aspects of Islam is deeply sacral relation to the heaven, the moon and the sun, spheres and stars. For example, Islamic ritual practice is strictly correlated with lunar calendar, and motion of the spheres is considered unconditional symbol of time. All that caused needs in exact astronomic knowledge. Besides that, in the Middle Ages, astrology, which recognized dependence of personal destiny on constellations of stars and planets as supreme divine creations, was a component of Islamic culture. Almost all first Muslim astronomers were from Central Asia, where Zoroastrian astrological and astronomical tradition developed in such centers as Merv and Khorezm. Observational astronomy had obtained a status of the most high-toned field of Islamic scientific knowledge. The most educated governors patronized it.
In the 1420s, Ulugbeg initiated the establishment of the large observatory in Samarkand. Here, during three decades, the medieval scholars, including outstanding astronomers Qazi-Zadeh Rumi, Djemshid Giyas ad-Din Kashi and Ali Kushchi, had been carrying out observation and measurements of celestial movements. In the Islamic world, proximal foregoers of Ulugbeg’s group were Umar Hayyam in the 11th century and Nasr ad-Din Tusi in the 13th century, which created ephemeris tables “Melik-shah Zidj” and “Ilkhani Zidj”. The Samarkand observatory became famous for the edition of “Ulugbeg Zidj”, containing theoretical introduction and tables of 1018 stars. The first part of the introduction is devoted to oriental computation; the second – to practical astronomy; the third – to theories of celestial movements; the fourth - to astrology. European scientists learned about the observatory in 1648, after John Grivs published some parts from “Ulugbeg Zidj” in Oxford. In 1665, T. Hide published “Tables of longitudes and latitudes of fixed stars upon Ulugbeg’s observations” in Oxford.
In difficult years of the late Middle Ages, the observatory was destroyed and fallen into neglect. By the 19th century, even location of the observatory had become forgotten. The honour of Ulugbeg observatory discovery belongs to outstanding Samarkand archeologist Vyatkin V. L., whose tomb is located beside the site of observatory. He excavated the observatory in 1908 on the rocky Kuhak hill at the feet of Chupanatin mounds. The eastern sector of the building was excavated in 1941, and the western - in 1948. The excavations revealed that the building had a form of a huge cylinder about 46 m in diameter and at least 30 m in height. Underground remains of the major instrument, which provided amazing accuracy of astronomic observations became the most important find. It was the largest medieval astronomic instrument - a vertical quadrant for observation of the Sun, Moon and the other celestial bodies. It was exactly oriented at meridian “south-north”. Arc radius was 40.21 m., and the length of the arc - 63 m.