Matsya Purana — Soma
दृष्टचन्द्रा त्वमावास्या मध्याह्नप्रभृतीह वै दिवा तदूर्ध्वं रात्र्यां तु सूर्ये प्राप्ते तु चन्द्रमाः सूर्येण सहसोद्गच्छेत् ततः प्रातस्तनात्तु वै //
dṛṣṭacandrā tvamāvāsyā madhyāhnaprabhṛtīha vai divā tadūrdhvaṃ rātryāṃ tu sūrye prāpte tu candramāḥ sūryeṇa sahasodgacchet tataḥ prātastanāttu vai //
That Amāvāsyā day is called “dṛṣṭa-candrā” (“moon-seen”): from midday onward, in the daytime itself, and thereafter at night—when the Sun reaches its time (of setting), the Moon rises suddenly together with the Sun; and then it is seen again at dawn.
This verse is not about Pralaya; it defines a calendrical/astronomical condition of Amāvāsyā (new-moon) where the Moon is considered ‘seen’ due to its brief visibility near the Sun and again at dawn.
It supports dharmic timekeeping: kings and householders rely on correct tithi identification (especially Amāvāsyā) for śrāddha, fasting, donations, and other rites whose merit depends on proper lunar timing.
The significance is ritual (not architectural): it indicates a special Amāvāsyā marked by moon visibility, helping determine precise performance windows for new-moon rites such as pitṛ-kārya (ancestral offerings) and other Amāvāsyā observances.