garga-saṁhitā
Garga, an astronomer whose name is found in the Mahabharata, where he is described as having an astronomical school at a place called Gargasrota in the Sarasvatī basin, is the reputed author of a pre-Siddhāntic calendaric treatise called Garga Saṁhita. He notes :
Yadā nivartatē ‘prāptaḥ śraviṣṭhām uttarāyaṇe
Aśleṣām dakśiṇo ‘prāptas tadā vindyān mahad bhayam.
Translation : When at the time of Ottarāyana the sun is found turning (north) without reaching the Sraviṣthās; and (at the time of Dakṣiṇāyana) turning (south) without reaching the Aśleṣā, it should be taken to indicate a period of calamity.
It shows that at the time of Garga the W.S. did no longer occur in Śraviṣthā, neither the S.S. occurred in the Aśleṣā division.
Garga, quoted by Somākara on Ved. Jy. 6, says (referring to older VJ epoch?):
यदा माघस्य शुक्लस्य प्रतिपद्य् उत्तरायणम् ।
सहोदयं श्रविष्ठाभिः सौमार्कौ प्रतिपद्यतः॥
mahābhāratam
In the Mahabharata we get the following verse :
Aśvamedha, Chap. 44;2:
Ahaḥ pūrvam tato rātrir
māsāḥ śuklādayaḥ smr̥tāḥ
śravaṇādīni r̥kṣāṇi
r̥tavaḥ śiśirādayaḥ
Translation : Day comes first and then the night ; months, are known to commence with the bright half, the nakṣatras with Śravaṇa, and the seasons with śiśira.
Here the asterism Śravaṇa is described as the one where the winter solstice takes place. śravaṇa is just preceding Sravistha and the solstices take about 960 years to retrograde through one nakṣatra division.