The Gateway to Liberation
Vaikuṇṭha Ekādaśī (also called Mokṣadā Ekādaśī — the Ekādaśī that grants liberation) falls on the eleventh day of the bright fortnight of the Tamil month Mārgazhi (December-January). It is the most celebrated of the 24 annual Ekādaśīs and draws millions of pilgrims to Śrī Raṅgam, Tirumalai, and other major Divya Deśams.
The Paramapada-vāsal
At Śrī Raṅgam, the central ceremony of Vaikuṇṭha Ekādaśī is the opening of the Paramapada-vāsal (the Door of Supreme Refuge / Door to Vaikuṇṭha) — a special gate in the inner prakarama. Passing through this gate is understood as a symbolic enactment of reaching Vaikuṇṭha. Hundreds of thousands of devotees queue through the night to pass through.
Nammāzhvār and the Adhyayana Utsavam
Vaikuṇṭha Ekādaśī is not Nammāzhvār’s tirunakṣatram; his avatāra star is Vaikāsi Viśākham. At Śrīraṅgam, Vaikuṇṭha Ekādaśī is the first day of Rā-pattu within the Adhyayana Utsavam. The ceremonial Nammāzhvār Mokṣam occurs at the conclusion of the Rā-pattu sequence, after the ten nights, not on Vaikuṇṭha Ekādaśī itself.