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instruments except rasivalaya for which an effort was made by garrel in 1907 to reconstruct it. However in the process, he changed it completely. Raja Jai Singh also built the observatory at Delhi.
3. Assessment of Ancient Indian Astronomy -
We start by giving a quotation from O. Neugebauer's 'A Histroy of Ancient Mathematical Astronomy' a scholarly work comprising 3 volumes and more than 1200 pages, published in 1976.
In spite of that pioneering work done by H.T. Colebrook (1765-1837), G. Thibault (1848-1914) and others, the study of Hindu astronomy is still at its beginning. The mass of uninvestigated manuscript material in India as well as in western countries is enormous. May it suffice to remark that many hundreds of planetary tables are easily accessible in American libraries? So far only a preliminary study of this material has been made revealing a great number of parameters for lunar planetary tables.
The Planetary tables are of great extent and based on methods so far not encountered in western materials, the basic idea being that the planetary positions are computed for a whole year as a function of the Aries. when these methods were developed, we do not know, the extent texts suggest the date of the fourteenth century AD.
This statement clearly establishes the need for a massive research effort. It is a testimonial to the originality of Indian work on astronomy.
There is a feeling that there has been some Greek influence on Indian astronomy, and two of the Siddhanta's show this influence. However, the Surya Siddhanta's which is purely Indian is far superior to them, and this was entirely due entirely to the great mastery of ancient Indians over arithmetic and algebra. The Greeks were superior in geometry, but astronomy required computations, and therefore the Greeks were not proficient in astronomy.
The independence of the two developments is testified by the fact that the parameters used are different; the methods of correction are different, the styles of presentation are different and mathematical backgrounds are somewhat different. Moreover, Indian astronomy was influenced much more by the needs of astronomers, Ujjain, the important centre of Indian astronomical activities, was taken as having zero longitude.
Astronomy is a practical subject, and truth in this field is obtained by successive approximations. The Hindus were always ready to give up the methods which gave wrong results, and were prepared to improve them. Starting with Panca Siddhantikā, each succeeding work gives more accurate methods than the 72 अर्हत् वचन 23 (3), 2011
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