Bodhāyana Amāvāsai is the separately calculated Darśa day followed by Bodhāyana-sūtra families for tarpaṇa and ancestral rites. Depending on how Caturdaśī, Amāvāsyā, and Pratipad span the ritual window, it can precede the date printed for other sūtra traditions; it is not unconditionally one day earlier. On the Panchang the civil date follows related tithi, nakṣatra, or saṅkramaṇa from local sunrise. Because tithi and nakṣatra boundaries are reckoned from local sunrise, the same observance can fall a day earlier or later in another city. Bodhāyana and allied prayoga traditions calculate the Darśa karma day from the tithi span across the relevant ritual window. That conditional calculation can select a different civil day from Āpastamba and other sūtra calendars, which is why this remains a distinct key. Observance includes mahā-saṅkalpa, piṇḍa or tarpaṇa to ancestors, and often a strict fast or single meal depending on family rule — the following day may be kept as the 'standard' Amāvāsyā by other communities on the same stretch. Cross-link the generic Amāvāsyā observance where relevant. This site does not yet carry a dedicated Bodhāyana sūtra or pitṛ-tarpaṇa manual page. Dates below for 2026 are computed from sunrise at your selected place. The same vrata can fall on an adjacent civil day in another city.
