Jyotiṣa-śāstra Saṅgraha: Threefold Division, Gaṇita Methods, Muhūrta, and Planetary Reckoning
रेखा प्राच्यपरा साध्या विषुवद्भाग्रया तथा । इष्टच्छायाविषुवतोर्मध्येह्यग्राभिधीयते ॥ १३४ ॥
rekhā prācyaparā sādhyā viṣuvadbhāgrayā tathā | iṣṭacchāyāviṣuvatormadhyehyagrābhidhīyate || 134 ||
Qu’on trace une ligne tournée vers l’est, et de même une ligne conforme à l’axe équinoxial (est–ouest). Le point nommé « agrā » est dit se tenir au milieu entre la marque d’ombre désirée et la marque d’ombre de l’équinoxe.
Sanatkumara (teaching Narada in a technical-vedanga style passage)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: bhakti
It shows that dharma and moksha-oriented life in the Purana is supported by precise knowledge (vidyā): correct orientation and time-reckoning (through shadow and equinoctial markers) safeguard the accuracy of rites and disciplined living.
While not directly a bhakti-verse, it supports bhakti-practice indirectly: accurate determination of direction and time helps perform Vishnu-oriented worship, vrata timings, and daily observances with steadiness and correctness.
Vedāṅga Jyotiṣa and chāyā-gaṇita (shadow-based measurement): drawing an east-oriented line, using the equinoctial (viṣuvat) reference, and defining a midpoint marker (agrā) for further calculation or alignment.