Matsya Purana — Measures of Time: Caturyuga Computation, Shloka 10
दिव्ये रात्र्यहनी वर्षं प्रविभागस्तयोः पुनः अहस्तु यदुदक्चैव रात्रिर्या दक्षिणायनम् एते रात्र्यहनी दिव्ये प्रसंख्याते तयोः पुनः //
divye rātryahanī varṣaṃ pravibhāgastayoḥ punaḥ ahastu yadudakcaiva rātriryā dakṣiṇāyanam ete rātryahanī divye prasaṃkhyāte tayoḥ punaḥ //
दिव्ये रात्र्यहनी वर्षरूपे भवतः। तयोः पुनः प्रविभागः—उदक्चलनम् (उत्तरायणम्) अहः, दक्षिणायनं रात्रिः। एते दिव्ये रात्र्यहनी एवं प्रसंख्याते॥
FAQs
It sets the cosmological time-scale used in Purāṇic narratives (including pralaya accounts): a human year equals one day-night of the gods, enabling larger calculations for yugas, manvantaras, and dissolution cycles.
By linking ritual and seasonal timing to uttarāyaṇa and dakṣiṇāyaṇa, it supports dharmic scheduling—auspicious periods for vows, gifts, and state or household rites aligned with the cosmic calendar.
Ritually, it highlights the north/south solar courses as key markers for calendrical observances; in Vāstu and temple practice, orientation and timing often reference these directions and seasonal transitions.