Jyotihshastra: Astral and Mathematical Literature c4.s6.18

c4.s6.18

Interest in the astrolabe was reawakened in north India in the Mughal period. The Risālat al-uṣṭurlāb of the great thirteenth century Persian polymath, Naṣīr al-Dīn Muḥammad al-Ṭūsī,²⁸⁴ was translated into Sanskrit at some time during this period. In 1615 at Jambūsara in Gujarāt Viśrāma wrote a Yantracintāmaṇi²⁸⁵ in which he describes the astrolabe, the gnomon, the water-clock, the quadrant, and several other instruments. Incidentally, he presents several elements borrowed from Islamic astronomy in addition to the astrolabe: tables of the Sine and Cosine functions at intervals of 1° with R = 120; a declination table with ε = 23;35°; and the goal year periods of the planets.²⁸⁶