Nasiraddin Tusi and development of astronomy

Ten devices and equipments were used in Maragha observatory for scientific experiments and observations. Five of those devices and equipments were known before the middle of XIII century, but other five were invented in Maragha observatory under the leader-ship of N. Tusi. Equipments and devices invented in Maragha observatory were used in Peking observatory of Chine, Ulugbek¿s observatory of Samarqand, Tycho Brahe¿s observatory of Denmark and Jaipur observatory of India established during next years and great works were carried out in order to improve those equipments. Let¿s give some information about mentioned observatories. The table of geographic coordinates of 256 cities was made in Maragha observatory and it was included in ¿Zij-i Ilkhani¿. Such table existed in ¿Zij-i Ulugbek¿ too. According to results of investigations, that table was copied from ¿Zij-i Ilkhani¿ to ¿Zij-i Ulugbek¿. Only coordinates of Samarqand were redetermined. There were sine and tangent charts in ¿Zij-i Ulugbek¿ too. But those charts were more exact that charts prepared in Maragha observatory.