Matsya Purana — Solar–Lunar Motions
नागवीथ्युत्तरा वीथी ह्य् अजवीथिस् तु दक्षिणा उभे आषाढमूलं तु अजवीथ्यादयस् त्रयः //
nāgavīthyuttarā vīthī hy ajavīthis tu dakṣiṇā ubhe āṣāḍhamūlaṃ tu ajavīthyādayas trayaḥ //
The Nāga-vīthī is the northern ‘lane’ (vīthī), while the Aja-vīthī is the southern. Both are rooted (begin) in Āṣāḍhā and Mūla; and beginning with the Aja-vīthī there are three such vīthīs in that grouping.
This verse is not about Pralaya; it is a technical classification of directional vīthīs (astral ‘paths’) tied to nakṣatra markers (Āṣāḍhā, Mūla).
It supports dharmic decision-making by grounding timing and orientation in traditional astral divisions—useful for rulers and householders when fixing auspicious directions/times for foundations, consecrations, or public works.
The verse assigns Nāgavīthī to the north and Ajavīthī to the south, and links them to Āṣāḍhā–Mūla markers—guidance that can be applied in Vastu-oriented orientation and in selecting ritual timings aligned with nakṣatra-based schemes.