Matsya Purana — Cosmic Architecture of Sun–Moon and the ‘Houses of the Gods’
शनैश्चरात्तथा चोर्ध्वं ज्ञेयं सप्तर्षिमण्डलम् सप्तर्षिभ्यो ध्रुवश्चोर्ध्वं समस्तं त्रिदिवं ध्रुवे //
śanaiścarāttathā cordhvaṃ jñeyaṃ saptarṣimaṇḍalam saptarṣibhyo dhruvaścordhvaṃ samastaṃ tridivaṃ dhruve //
Above Śanaiścara (Saturn) one should understand the sphere of the Saptarṣi-maṇḍala, the circle of the Seven Sages. Above the Seven Sages is Dhruva (the Pole Star); and the entire threefold heaven is established with Dhruva as its fixed pivot.
It does not directly describe Pralaya; it presents the Purāṇic cosmographic idea that the heavens remain ordered around Dhruva as a fixed cosmic axis, implying stability and structure in the universe’s design.
Indirectly, it supports the Matsya Purana’s broader ethic that rulers and householders should align life with cosmic order (ṛta/dharma): just as the heavens are oriented around a fixed pivot (Dhruva), human conduct should be grounded in steadfast principles.
No direct Vāstu rule is stated, but Dhruva as a ‘fixed pivot’ parallels ritual and temple-orientation ideals—establishing sacred spaces with stable directional awareness (especially the north and the pole-star axis) in Puranic practice.