Ulugh-Beg or Ulug-Beg, 1394-1449, Timurid ruler and astronomer. The grandson of Timur (or Tamerlane), he succeeded to the Timurid domain in 1447. A patron of the arts and sciences, he established an astronomical observatory at Samarkand and compiled a star catalog (1420-37). His work, written in Arabic, was translated into Persian. It became known in Europe in the 16th cent. and a Latin version appeared in England (1665). A small museum of astronomy now stands on the remains of his observatory.