The Astronomical Observatories of Jai Singh c16.1

c16.1

79. The history of the evolution of Jai Singh's astronomical instruments would, if it could be recorded, step by step, be of great interest; but detailed descriptions of the larger Arabic instruments are not generally available, and we must, for the present, be content with general indications of the lines of development. Generally speaking, Jai Singh's instruments are copies of, or direct developments from, those used by Ulugh Beg and his predecessors and successors. The flat astrolabe played an important part. Jai Singh's first attempt at improvement was apparently the construction of huge astrolabes, such as those shown in figures 28 and 29, and the construction of large graduated circles. He had some excellent Arabic and Persian models (figures 5—20) but the metal instruments he had constructed do not appear to be of that fine workmanship that adds so much to the value of many of the mediæval astrolabes. As far as can be gathered Jai Singh did not use the ordinary sextant and quadrant instruments, such as were used by Naṣīr al-Dīn Ṭūsī, Tycho Brahe, Flamsteed, and others.