Matsyapurana 124.54

124.54

abhijitpūrvataḥ svātiṃ nāgavīthyuttarās trayaḥ
aśvinī kṛttikā yāmyā nāgavīthyas trayaḥ smṛtāḥ //

The sun appears high (on the horizon) when He reaches the centre of Puṣkaradvîpa. He travels over the 1/30th of the world in one muhûrta (a period of 48 minutes). That is to say, the speed of the sun in one muhûrta (48 minutes) is 31,50,000 yôjanas (1/30 of 9,45,00,000). Thus gradually He marches to the south. In His southward course (Dakṣiṇâyana), He travels in the space between Mânasôttara and Meru thrice as much as in the centre of Puṣkara. Now hear of his southward course. He covers the whole circumference of the earth, 9,45,00,000 yôjanas, in course of a day and night. After finishing his southward course when he comes at the equator (Viṣava rekhâ), he travels over (lights up) the north of the Kṣîrasâgara, as well as the Viṣuvamaṇḍala, whose extent all of you now hear. It is 3,21,00,000 yôjanas. In the month of Srâvaṇa the sun in his northern course travels over Puṣkaradvîpa, which is beyond the Gômedadvîpa. The extent of the northern, southern and the middle of this journey should be noted as below. Jaradgava is in the middle, Airâvata in the north and Vaiśvânara in the south. Nâgavîthî is the Uttarâvîthî (_i.e._, northern course begins with Nagavîthî?). Ajavîthî is the Dakṣiṇâvîthî, with Ajavîthî begins the southward course? The asterisms P. Asâḍha and U. Asâḍha, as well as the Mulâ, Asvinî, Bharaṇi, and Krittikâ form the Nâgavîthî. Rohiṇî, Ârdrâ and Mrigaśira are also Nâgavîthî (or Gajavîthî).

The two Âṣaḍhâs and the Mûlâ (constituting the vîthi called Vaiśvânara, along with the two vîthis west of it, namely,) beginning with Ajavîthi (that is, Ajavîthi and Mṛigavîthi) or the two vîthis, East of Abhijit and ending with Svâti are the three vîthis north of the Nâgavîthi.