ABSTRACT
Astronomy is known to have been cultivated in the 'house of wisdom' of Harun al Rashid, the fifth caliph, in Baghdad; and its study progressed greatly in the next century under Al Mamun, the seventh caliph. Ulugh Bek's interests in astronomy must have been awakened early in his life, while he was still prince and heir-apparent to his father Shah-rukh; at least work on the building of the observatory in Samarkand was started some time between 1420 and 1427. The world of Islam, especially at the peak of its intellectual creativity between the eighth and twelfth centuries, indeed made great contributions to observational astronomy. The simplistic approach to duty by our predecessors can be understood only if we remember that the astronomy of Bessel or Gauss was governed by one very simple physical law (that of gravitation, which represents the weakest force operating in nature).
