In determining the date of the Mahabharata war at Kurukshetra, astronomical references in the epic can be used, of which there are more than one hundred and fifty. Most of these that pertain to the war, though there are many scattered throughout the texts, is in the Udyoga and Bhisma Parvas. Those in the Bhisma Parva are especially systematic and are also in accordance with the astrological omens described in the Atharva Veda and its Parishishtas, referring mostly to comets. When these are put together with the retrograde motion of Mars before reaching Jyestha, this leads to the unique date of 3067 BCE for the date of the war, which was previously proposed by Professor Raghavan.
This corroborates with the view that the age of Kali-yuga started in 3102 BCE, according to Dr. Achar. As stated in the Puranas, Kali-yuga had already begun, but its full influence was held back because of the presence of Lord Krishna. Then when Lord Krishna departed from this world, which is said to have occurred 35 years after the war of Kurukshetra in 3067, making it the year of 3032 BCE, then Kali-yuga began to show more of its effects.
In the time line for the passing away of Grandfather Bhisma, for example, it is said that Bhisma passed away on the Magha (January-February) shukla ashtami, after the winter solstice, which leads to the date of January 13, 3066 BCE for the winter solstice.
So, in considering the chronology according Professor Raghavan, we have:
Lord Krishna’s departure from Upaplavya nagara on the mission for peace–September 26, 3067 BCE.
Krishna reaches Hastinapura–September 28, 3067 BCE.
Lunar eclipse–September 29, 3067 BCE.
Krishna rides with Karna–October 8, 3067 BCE.
Solar eclipse–October 14, 3067 BCE.
The war begins–November 22, 3067 BCE.
Fourteenth day of the war, continued into the wee hours of the morning–December 8, 3067 BCE.
Balarama returns–December 12, 3067 BCE.
Winter solstice–January 13, 3066 BCE.
Bhisma’s passing away–January 17, 3066 BCE.
Departure of Lord Krishna– 3031 BCE.
About when Vedavyasa composed the main Vedic texts– 3000 BCE.
About when the Sarasvati had dried up or disappeared–1900 BCE.