The winter solstice in the beginning of Uttara Phâlgunî in the month of Shrâvana.
The vernal equinox in the beginning of Mûla in Kârttika.
The summer solstice in the beginning of Pûrva Bhâdrapadâ in Mâgha.
The autumnal equinox in the beginning of Mrigashîrsha in Vaishâkha.
A Proof from the Bhagavad Gîtâ.
13. The Bhagavad Gîtâ, as well as the Bhâgavata, makes mention of an observation which points to a still more remote antiquity than the one discovered by Mr. Bentley. The passages are given in order below:
“I am the Mârgashîrsha [viz. the first among the months] and the spring [viz. the first among the seasons].”
This shows that at one time the first month of spring was Mârgashîrsha. A season includes two months, and the mention of a month suggests the season.
“I am the Samvatsara among the years [which are five in number] and the spring among the seasons, and the Mârgashîrsha among the months and the Abhijit among the asterisms [which are twenty-eight in number].”
This clearly points out that at one time in the first year called Samvatsara, of the quinquennial age, the Madhu, that is, the first month of spring, was Mârgashîrsha, and Abhijit was the first of the asterisms. It then coincided with the vernal equinoctial point, and thence from it the asterisms were counted. To find the date of this observation: There are three asterisms from the beginning of Mûla to the beginning of Abhijit, and hence the date in question is at least 16,301 + 3/7 × 90 × [pg 356]72 = 19,078 or about 20,000 b.c. The Samvatsara at this time began in Bhâdrapadâ, the winter solstitial month.