The Three Twilight Prayers
Sandhyāvandana ('salutation at the twilight junctions') is the most fundamental nitya-karma (daily mandatory duty) for an initiated Brahmin Sri Vaishnava. It is performed three times daily: at dawn (prātaḥ-sandhyā), at noon (mādhyāhnika), and at dusk (sāyaṃ-sandhyā) — the three transition points (sandhyā = junction) of the day.
Structure of the Rite
The core elements: (1) ācamana — ritual sipping of water while reciting the Lord's names, for internal purification; (2) prāṇāyāma — breath regulation with mantra, purifying the subtle body; (3) arghya-pradāna — offering water to the sun three times while reciting the Gāyatrī mantra; (4) Gāyatrī japa — silent repetition of the Gāyatrī mantra (the Vedic prayer to the divine light) in prescribed numbers; (5) prayers and rites specific to each of the three times.
Sri Vaishnava Modifications
In Sri Vaishnava practice, the sandhyāvandana incorporates invocations of Viṣṇu and the use of the ūrdhvapuṇḍra tilaka. The ācamana uses the aṣṭottara names of Viṣṇu. The tradition received from the ācārya specifies the proper form of each element.
Theological Framing
For the prapanna, sandhyāvandana is not performed as a means to liberation but as a loving daily service to the Lord — the sun being a form in which the Lord's light is worshipped. Omission is considered a dharma-lopa (fault in dharma) that requires atonement.