Kara?apaddhati of Putumana Somayaji

Kara?apaddhati presents the theoretical basis for the vakya system, where the true longitudes of the planet are calculated directly by making use of certain auxiliary notions such as the kha??a, ma??ala and dhruva along with tabulated values of changes in the true longitude over certain regular intervals which are expressed in the form of vakyas or mnemonic phrases. The text also discusses the method of vallyupasa?hara, which is essentially a technique of continued fraction expansion for obtaining optimal approximations to the rates of motion of planets and their anomalies, involving ratios of smaller numbers. It also presents a new fast convergent series for p which is not mentioned in the earlier works of the Kerala school. As this is a unique text presenting the rationale behind the vakya system and the computational procedures used in the kara?a texts, it would serve as a useful companion for all those interested in the history of astronomy. The authors have provided a translation of the text followed by detailed notes which explain all the computational procedures, along with their rationale, by means of diagrams and equations.

K. RAMASUBRAMANIAN is professor at the Cell for Science and Technology in Sanskrit, Indian Institute of Technology (IIT) Bombay. He worked on nonlinear dynamics to obtain his PhD from the University of Madras in 2001. He has been working in the area of Indian astronomy and mathematics for more than 25 years and is also a scholar in Advaita-Vedanta. He was awarded the Maha??i Badaraya?a Vyas Samman by the President of India in 2008.

M.S. SRIRAM worked on field theory and obtained his PhD in physics in 1978 at Indian Institute of Technology (IIT) Kanpur. He was a faculty member at the Allahabad University for five years. Subsequently, he joined the Department of Theoretical Physics, University of Madras, and retired as the head of the department in 2011. He has worked in the areas of high energy physics and nonlinear dynamics. He has been engaged in research in Indian astronomy and mathematics for over 25 years. Presently he is associated with Prof. K.V. Sarma Research Foundation, Chennai.

M.D. SRINIVAS did his PhD in the theoretical physics at the University of Rochester, U.S.A. He was a faculty member at the Department of Theoretical Physics, University of Madras, for two decades and worked on the conceptual and mathematical foundations of quantum mechanics. He has been associated with the Centre for Policy Studies, Chennai, for over two decades and has been working on various aspects of Indian sciences, society and polity.