Mausala parva ch.3 of mahābhārata says that Lord křşņa left this earth after 36 years had elapsed from the great war. And kaliyuga could not begin as long as He was touching this earth with his holy feet.(Vişņu purāņa- 4).

It is only after Křşņa left this mundane world the present kaliyuga commenced. The current year being 5122 of the kaliyuga samvat, marks the beginning of kali as 3102BC and commencement of war as 3139/8 BC.

Vřddha garga's verse "Asan maghasu Munayah Sasati prudhivim Yudhişțhire nřpātan, şađ dvika Pañća diryutah Śaka kāla stasya Rājñyasya" is also mentioned by Varāhamihira in brihatsamhitā. This clearly states the situation if saptařśi in maghā nakşatra and the interval between+

+his time śaka kāla is 2526 years. And from authentic oriental sources(kalhaņa has misconceived in rājatarańginī)it is clear that śaka kāla refers to the era of Cyrus śakasthāna which started in 550BC, not to be confused with śālivāhana śaka of 78AD.

So Yudhişțhira's time must have ended by 3077/6BC (2526+550). All the purāņa~s say that Yudhişțhira lived for 25 years after the commencement of this kaliyuga. Hence the commencement of kaliyuga comes out to be 3102BC and the great war began 36 years before that, ie 3139BC.

All the purāņa~s assert that: 1.the saptařşi~s entered aşleśā after 25 years elapsed from the commencement of the present kaliyuga 2.saptařşi had completed one cycle since yudhişțhira. 3.commenced their second round during 27th Andhra king. As this would take 2700 years, the era+

+of either Puloman 2 or śiva śrī śatakarņī being 377BC, again confirms 3077BC as that year and commencement of kaliyuga in 3077+25= 3102BC.

According to mahābhārata Śānti parva verse:1-4, Bhīşma clearly tells Yudhişțhira that a 4th part of the māgha month was over, ie 7+1/2 tithi~s had gone when when Bhīşma decides to go to vaikuņțha. As one tithi makes a distance of 12degrees in the ecliptic, the distance between+

+moon and sun was 90degrees(12×7.5). So, the sun must have been at the time of Bhīşma's death at 319deg-33'-20"(śrī nārāyaņa śāstrī in the age of śańkara). From the above mentioned verses, it is also clear that the winter solstice had commenced at about midnight of previous day

(Bhīşma says sun has started northward journey, and last rites can only be performed during day). Thus, the position of sun at winter solstice comes out to be 318deg-3'-20". If we compare the position of sun on winter solstice now in our age, and applying the ayanagati(precession

+of equinoxes)as 59deg26' per year, we will eventually be able to evaluate the time lag at this rate between the position of sun at the time Bhīşma's death and today. This comes as almost 5160 years aporox. This clearly shows that the war ended in 3139BC.

We must also not ignore Aryabhațța when he himself says शष्टयब्दानां शष्टिर्यदा....
ie when 3600(60×60) years passed of this yuga, then 23 years elapsed since my birth. This also points to 3102BC being the beginning year of kaliyuga.

Nārāyaņa śāstrī says bhīşma breathed his last at 15 ghațika~s after sunrise. Rohiņī on that day should have ended at about 32 ghațika~s after sunrise. https://twitter.com/mmpandit/status/1264915397918236674?s=19

https://twitter.com/mmpandit/status/1264915397918236674?s=19
Jupiter and Saturn were near Viśākhā, and not jyeşțha at the time of battle.

https://twitter.com/mmpandit/status/1264917125321363456?s=19
It is clear from the śalya parva(34:6:1,2) that balarāma jī departed for tīrtha in puşya nakşatra and returned in śrāvaņa to observe the battle between his two disciples. Karapātrī jī is clears this discrepancy in a smooth way.

If we assume the ultimate day of war in śravaņa and on the basis of 18 days of the battle, it comes out that tbe war would have commenced in mřgaśira, ie pūrņimā or śukla ćaturdaśī of mārgaśīrşa.

Moreover from aśvamedhika parva(14:19-20), it is clear that kaliyuga was just about to arrive during the reign of king Yudhişțhira.

https://twitter.com/mmpandit/status/1264915991454273539?s=19
Vedavyāsa expresses his amaze over the solar and lunar eclipses in a span of 13 days(lapse of 2 tithi~s resulted in 13days of křşņa pakşa). [Bhīşmaparva 3/2]

This is again endorsed by Śrī Křşņa when He exclaims that Rāhu had transformed Ćaturdaśī into amāvasyā just as it happened during the bhārata yuddha. [Mausala parva 2/18,19]

If we cautiously read Bhīşmaparva:2/23&3/33, it is conspicuous that the křşņa Ćaturdaśī in focus is the one 'after' kārtikī pūrņimā as clear from 'आसीत'. And Śīghrabodha 4/161 also says that a month observing solar & lunar eclipses brings kings and havoc in the battlefield.