Ancient Indian Astronomy : Planetary Positions and Eclipses

Contents:  Preface. 1. Introduction—historical survey. 2. Zodiac and constellations. 3. Co-ordinate systems. 4. Yuga system and eras. 5. Ahargana. 6. Motions of the sun and the moon. 7. True positions of the sun and the moon. 8. True daily motions of the sun and the moon. 9. Lunar eclipse. 10. Solar eclipse. 11. Mean positions of the star-planets (Kuja, Budha, Guru, Sukra and Sani). 12. True positions of the star-planets. 13. Suggested improved procedures for eclipses. 14. Suggested Bijas (corrections) for planets’ positions. Computer programs. Appendices: 1. Precession of equinoxes. 2. Lagna (ascendant). Bibliography. Glossary of technical terms in Indian astronomy. Index.

“The book Ancient Indian Astronomy—Planetary Positions and Eclipses is mainly addressed to students who are keenly interested in learning and becoming proficient in the concepts, techniques and computational procedures of Indian astronomy.

The procedures and algorithms described succinctly in the popular Indian traditional texts like Khanda Khadyaka of Brahmagupta, Surya Siddhanta and Graha Laghavam of Ganesa Datvajna for (i) the mean and true positions of the sun and the moon, the taragrahas (star planets) and (ii) computations of lunar and solar eclipses are elaborated with actual examples.

A unique and pioneering feature of the book is providing ready-to-use computer programs for the above-cited procedures, which can be readily used by the students and researchers in the field of astronomy for computations of planetary positions and eclipses according to the popular Indian astronomical texts used in this work and for a comparative study.

Appendices present the effect of the phenomenon of precession of equinoxes and the resulting ayanamsa, relevant to Indian astronomy and the computation of lagna, the orient ecliptic point (ascendant) according to the traditional Indian method respectively. To enhance the usefulness of the book, a detailed bibliography of the original Sanskrit works and also of the secondary sources in English is provided. Fairly exhaustive glossary of technical words and an index, for ready reference, form the last part of the book.

A sincere attempt has been made to contribute significantly to the field of astronomy by (i) providing suggested improved procedures for computing lunar and solar eclipses, and (ii) suggesting bijas (corrections) for planetary positions to yield better results comparable to modern ones. “ (jacket)

[S. Balachandra Rao has also written Indian Mathematics and Astronomy—Some Landmarks.]