Matsya Purana — Ravi-Saṅkrānti Vow: Udyāpana
रविसंक्रमणे भूमौ चन्दनेनाष्टपत्त्रकम् पद्मं सकर्णिकं कुर्यात् तस्मिन्नावाहयेद्रविम् //
ravisaṃkramaṇe bhūmau candanenāṣṭapattrakam padmaṃ sakarṇikaṃ kuryāt tasminnāvāhayedravim //
At the time of the Sun’s transit (saṅkramaṇa), one should draw on the ground—using sandal paste—an eight-petalled lotus complete with its central pericarp; and upon that, one should invoke the Sun (Ravi).
This verse does not discuss Pralaya; it prescribes a saṅkramaṇa-time ritual for invoking the Sun using an eight-petalled lotus diagram.
It reflects the householder/royal duty of maintaining auspicious observances on calendrical junctions (saṅkramaṇa), performing orderly worship (upāsanā) and invocation (āvāhana) as part of dharmic routine.
Ritually, it specifies a ground-based mandala (aṣṭapattra-padma with karṇikā) drawn in sandal paste as the seat for āvāhana of Surya—an iconographic/diagrammatic support for worship rather than a building rule.