I wont dispute the astronomical data in the epic literature, however any early date for the ealy puranas, the Ramayana and the Mahabharata, does not appear to have any resonance with the archaeological data. Prof B.B Lal, Independent India's first DG of ASI, carried out a series of excavation , called the Archaeology of Mahabharatha and Ramayana, where he excavated in the sites traditionally associated with the epics like Hastinanapura, Ahichchhatra , Kosambi, Sravasti etc, and was able to detect evidence for settlements only as old as 1200 BCE( the painted grey ware culture)
Even if we take into accounts the recent attempts that have been made to associate new archaeological sites in Sanauli and the OCP sites to the epic period, even then it would be 2000 BCE at the earliest. Epics describe a society that was reasonably well developed with walled settlements, existence of a functioning state, knowledge of iron metallurgy , primitive coinage system. All the archaeological evidence for such a society in Gangetic India is not older than 1300 BCE.