Jyotiṣa-śāstra Saṅgraha: Threefold Division, Gaṇita Methods, Muhūrta, and Planetary Reckoning
शंकुच्छायाहते त्रिज्ये विषुवत्कर्कभाजिते । लंबाक्षज्ये तयोस्छाये लंबाक्षौ दक्षिमौ सदा ॥ १३८ ॥
śaṃkucchāyāhate trijye viṣuvatkarkabhājite | laṃbākṣajye tayoschāye laṃbākṣau dakṣimau sadā || 138 ||
トリジャー(trijyā、半径)にシャンクの影(śaṅku-chāyā)を掛け、分点および蟹宮(Cancer)の標準量で割ると、その得量はランバークシャ・ジャー(lambākṣa-jyā)、すなわち緯度の正弦である。かくして得た二つの影より、二つの緯度は常に南(dakṣiṇa)として取るべし。
Sanatkumara (teaching Narada in a Vedanga/astronomical context)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: adbhuta
It shows that Narada Purana integrates Moksha-oriented teaching with Vedāṅga Jyotiṣa: precise knowledge of time, direction, and seasonal markers supports correct dharma-practice and disciplined living.
Indirectly: by emphasizing accurate astronomical reckoning (equinox/seasonal measures), it safeguards the proper timing of vrata and pūjā—practical supports that strengthen steady Vishnu-bhakti.
Vedāṅga Jyotiṣa and mathematical astronomy: using a gnomon’s shadow with trijyā and jya (sine) operations to derive lambākṣa (latitude) and determine southern orientation.