Narada Purana — Purva Bhaga, Shloka 131
Graha–Ketu–Utpāta Lakṣaṇas: Solar/Lunar Omens, Comets, Eclipses, and Calendar Rules
तपास्तपस्य क्रमशश्चैत्रादीनां समाह्वयाः । यस्मिन्मासे पौर्णमासी येन धिष्ण्येन संयुता ॥ १३१ ॥
tapāstapasya kramaśaścaitrādīnāṃ samāhvayāḥ | yasminmāse paurṇamāsī yena dhiṣṇyena saṃyutā || 131 ||
Tapas 与 Tapasya，依次也是从恰伊特罗月（Caitra）起诸月所赋之名。每一月皆以其内所逢满月日（pūrṇimā）以及该满月所合之月宿（nakṣatra）而得以辨识。
Sanatkumara (in dialogue with Narada)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: adbhuta
FAQs
It frames sacred time as a dharmic structure: months are not merely civil labels but are ritually meaningful, defined through Paurṇimā and nakṣatra-conjunctions that guide observances and vows.
By clarifying the sacred calendar, it supports bhakti-practice indirectly—helping devotees perform vrata, pūjā timings, and festival observances on correct tithis and nakṣatra-yogas, which strengthens disciplined devotion.
Jyotiṣa (Vedāṅga astronomy/astrology): determining month-names and ritual months through the full moon (Paurṇimā) and its associated nakṣatra, a key rule for calendrical computation.