Matsya Purana — Cosmic Architecture of Sun–Moon and the ‘Houses of the Gods’
शनैश्चरं पुनश्चापि रश्मिराप्यायते सुराट् न क्षीयते यतस्तानि तस्मान्नक्षत्रता स्मृता //
śanaiścaraṃ punaścāpi raśmirāpyāyate surāṭ na kṣīyate yatastāni tasmānnakṣatratā smṛtā //
And again, O sovereign, even in the case of Śanaiścara (Saturn), its ray is replenished; since those luminaries are not diminished, therefore they are remembered as ‘nakṣatras’—imperishable star-lights.
It does not describe Pralaya directly; it explains a cosmological principle that celestial bodies (including Saturn) do not ‘wear out’ because their radiance is continually replenished.
By addressing the king, it frames astral knowledge as part of royal and household prudence—supporting timekeeping, calendrical observances, and auspicious decision-making guided by nakṣatras and grahas.
No explicit Vāstu rule is stated, but the idea of stable, non-diminishing luminaries underpins nakṣatra-based muhūrta selection used in temple rites, consecrations, and other ritual scheduling.