यस्य मन्वन्तरस्यादौ रथारूढो दिवाकरः । माघमासस्य सप्तम्यां सा तु स्याद्रथसप्तमी
yasya manvantarasyādau rathārūḍho divākaraḥ | māghamāsasya saptamyāṃ sā tu syādrathasaptamī
Le septième tithi du mois de Māgha — où, au commencement d’un Manvantara, le Soleil (Divākara) est dit monter sur son char — est appelé Rathasaptamī.
Skanda (deduced from Prabhāsa-khaṇḍa Māhātmya dialogue context)
Tirtha: Rathasaptamī (Māgha-śukla Saptamī)
Type: ghat
Scene: At dawn on Māgha Saptamī, the Sun-god rises, radiant, mounting a golden chariot; devotees at a coastal tīrtha offer arghya with cupped hands, lotuses, and copper vessels; the sky glows saffron.
Certain tithis are sanctified by cosmic beginnings; honoring them (especially with devotion and giving) aligns one with dharma and brings enduring merit.
The broader frame is Prabhāsakṣetra (Somnāth–Prabhāsa region), where such sacred calendrical observances are praised as especially meritorious.
It identifies Rathasaptamī (Māgha Śukla Saptamī) as a distinguished tithi—implicitly a recommended day for vrata, worship of Sūrya, and merit-yielding acts like dāna.