The eclipses and planetary observations of the Mahabharata should belong to 1493 BC to 1443 BC of Indian history. The war should have taken place in 1478 BC with an error bond of one year, Dr R N Iyengar from the department of civil engineering at Indian Institute of Science in Bangalore, said.
This is a new date proposed for the Mahabharata War. Dr. Subhash Kak wrote an article on the same issue in Sulekha and his conclusion was
This leaves us with the dates of 1924 BC and 3137 BC. I don't think we have evidence at this time to pick one of these two as the more likely one. If one gives credence to the Puranic genealogies, then 1924 BC would be the time for the War; if, on the other hand, we go by the astronomical evidence related to the Vedas and the subsequent literature, then 3137 BC remains a plausible date. If the pre-Nanda Puranic lists are not accurate for the regnal periods, then the War will have occurred a few centuries later than 1924 BC.
This is an issue I had investigated deeply. If you want to know the exact date of Mahabharata, then read my article When Did Mahabharata Happen?
(thanks ashwini for the link)