Narada Purana — Purva Bhaga, Shloka 70
Jyotiṣa-śāstra Saṅgraha: Threefold Division, Gaṇita Methods, Muhūrta, and Planetary Reckoning
उदयादुदयं भानोर्भूमैः साचेन वासराः । वसुव्द्यष्टाद्रिरूपांकसप्ताद्रितिथयो युगे ॥ ७० ॥
udayādudayaṃ bhānorbhūmaiḥ sācena vāsarāḥ | vasuvdyaṣṭādrirūpāṃkasaptādritithayo yuge || 70 ||
从太阳一次升起到下一次升起，在大地上这段度量称为“婆娑罗”（vāsara，一日）。在一劫（yuga）中，提提（tithi，月日）的数目依词数而计：vasu、dvi、aṣṭa、adri、rūpāṅka、sapta、adri。
Sanatkumara (teaching Narada in a Moksha-Dharma context with technical time-reckoning)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: none
FAQs
It grounds dharma and moksha practice in correct kāla (time): vows, worship, and scriptural duties rely on precise day-and-tithi reckoning, so the Purana defines the day by the Sun’s sunrise-to-sunrise cycle.
Bhakti practices (vratas, fasts, pūjā timings) are performed according to tithi and vāsara; by clarifying how time is measured, the text supports disciplined, accurate devotional observance.
Jyotiṣa Vedāṅga: the definition of vāsara (solar day) and the use of bhūta-saṅkhyā (word-numerals like vasu=8, adri=7) to encode large calendrical counts such as yuga tithis.