While reading the Mahabharata text, I ran into the story of sage Dhaymya (specifically Ayoda-Dhaumya) and his three disciples – Aruni, Upamanyu and Veda. (Mahabharata, Adi Parva, Adhyaya 3)
They all were contemporary of King Janmejaya, some ~60 years after the Mahabharata War (5561 BCE) and thus contemporary of Mahabharata.
Readers may be aware that King Parikshit who was born immediately after the Mahabharata War lived for 60 years. At this time his son, Janmejaya, began his rule of Hastinpura.
Mention of Ashwini (nakshatra) in the story of Upamanyu is very significant for its details.
The story has astronomy flavor….
Upamanyu went roaming around, while hungry ate the leaves of Arka tree in a forest (note Arka also mean the sun) and he became blind and while walking in that state, fell into a deep well. His Guru – Ayoda-Dhaumya, asked Upamanyu to pray to Ashiwni.
Upamanyu praised Ashwini (Adi Parva 3:57-70)
I will refer to specific verses of interest to us, at this point.
(Adi Parva 3:58)
“You (Ashwini) weave the wonderful cloth of night and day by the black and while threads. You have established with the cloth thus woven two courses of action; one regarding the Devas (while path- sun’s travel from the point of winter solstice to the point of summer solstice) and the other regarding the Pitris (black path – sun’s travel from the point of summer solstice to the point of winter solstice).”
Adi Parva 3:62
“The wheel of time represented by the year has also a nave, the six seasons. It has spokes – 12 months”
Above verses refers to position of nakshatra Ashwini in the context of either winter solstice and/or summer solstice.
(There are numerous corroborative references from late sections of Rigveda-Upamandalas, for nakshatra Ashwini near Winter solstice, following relative chronology scheme of Shri Shrikant Talageri. I will not go into those references here, however it is also important to recognize that it was Vyasa, contemporary of Mahabharata times, who edited and re-casted the version of Rig-Veda we see today)
If one simulates the day of winter solstice (e.g. year 5500 BCE, time of King Janmejaya), first nakshatra that became visible on the western horizon, after the sun of winter solstice, set below horizon, was nakshatra Ashwini!
Thus, while this set of observations, by itself, is not sufficient to derive/establish/suggest any specific timeline for the timing of Mahabharata War, it (Ashwini, Upamanyu, Ayoda-Dhaumya – Adi Parva , Adhyaya 3) provides excellent corroboration for 5500 BCE as the timing of King Janmejaya and thus 5561 BCE as the year of Mahabharata War.