Matsya Purana — Cosmic Architecture of Sun–Moon and the ‘Houses of the Gods’
बुधेन समरूपाणि विस्तारान्मण्डलात्तु वै तारानक्षत्ररूपाणि हीनानि तु परस्परम् //
budhena samarūpāṇi vistārānmaṇḍalāttu vai tārānakṣatrarūpāṇi hīnāni tu parasparam //
From Budha (Mercury), the star- and constellation-forms are said to be similar in shape; yet in their orbital spheres (maṇḍalas) and in their extent they differ from one another, each being smaller or larger relative to the others.
This verse is not about Pralaya; it belongs to a cosmological-astronomical description, explaining how stars and nakṣatras are classified by form and differentiated by relative extent within celestial spheres.
Indirectly, it supports the Purāṇic ideal that rulers and householders should understand cosmic order (ṛta/dharma) through traditional sciences like Jyotiṣa, used for calendrical timing, rituals, and public observances.
No direct Vāstu or temple-rule appears here; the practical ritual takeaway is calendrical—knowledge of nakṣatras and planetary spheres underlies auspicious timing (muhūrta) and observances in Purāṇic practice.