Surya Siddhanta (सूर्य सिद्धांता)
Sūrya Siddhānta is an ancient Indian treatise in Astronomy. Like many classical Indian works, the Sūrya Siddhānta is a poem in Sanskrit language. It has fourteen chapter and 500 verses. It is composed in śloka metrical style of Sanskrit. It contain works on Indian sine tables, cosmology, eclipses, planetary motions, conjunctions, star positions, geography, instrumentation, concepts of time and mathematics. Unlike conventional books Sūrya Siddhānta contains advanced calculation and methods which are not easily comprehensible for a rank beginner. [1] The text had been updated several times and the last update appears to have been made around 580 CE to the Nakshatra longitudes. In second chapter, the text contains the calculation of Earth's obliquity of 1397 jya (R.sine) 23.975° modern units indicating the time of calculation around 3000 BCE. There are several other observations in the tradition of Indian Astronomy that were also recorded in the vicinity of 3000 BCE. This could possibly be the time of the origin of Sūrya Siddhānta although scholars do not seem to have a consensus on the origin of this text of Indian Astronomy.
History
''Sūrya Siddhānta'' is well known, most referred and most esteemed. The original author of ''Sūrya Siddhānta'' is ''Mayasura'' as described in the story in the first chapter that ''Mayasura'' obtained his knowledge from ''Sūrya'' (the Sun). ''Siddhānta'' in Sanskrit means ''treatise'' and it usually has author's name prefixed to it. There were several other works on Astronomy in ancient India, many of which have since been lost.
| Surya Siddhānta | Brahma Siddhānta | Soma Siddhānta |
| Vyasa Siddhānta | Vashishtha Siddhānta | Atri Siddhānta |
| Parashira Siddhānta | Kashyap Siddhānta | Nārad Siddhānta |
| Garga Siddhānta | Marici Siddhānta | Manu Siddhānta |
| Angiras Siddhānta | Lomasha Siddhānta | Pulisha Siddhānta |
| Cyavana Siddhānta | Yavana Siddhānta | Bhrigu Siddhānta |