The Tantrasaá¹ graha, composed by the renowned Kerala astronomer NÄ«lakantha SomayÄjÄ« (c. 1444â1545 AD), ranks along with the Äryabhaá¹Ä«ya of Äryabhaá¹a and the SiddhÄntaÅiromaá¹i of BhÄskarÄcÄrya as one of the major works which significantly influenced further work on astronomy in India. One of the distinguishing features of this book is the introduction of a major revision of the traditional Indian planetary model. NÄ«lakaá¹á¹ha arrived at a unified theory of planetary latitudes and a better formulation of the equation of centre for the interior planets (Mercury and Venus) than was previously available. In preparing the translation and explanatory notes, the authors have used authentic Sanskrit editions of the Tantrasaá¹ graha by Surand Kunjan Pillai and K. V. Sarma. All verses have been translated into English, which have been supplemented with detailed explanations including all necessary mathematical relations, illustrative examples, figures and tables by using modern mathematical notation. The book includes a glossary of frequently occurring Sanskrit terms and several appendices that serve to clarify many concepts relevant to the topics discussed in the main text.
