Kārttikai — The Month of Lamps and Divine Light
Kārttikai (named after the Kārttika nakṣatra — the Pleiades star cluster, one of the 27 lunar mansions; the month when the full moon occurs near the Kārttika nakṣatra) is the eighth month of the Tamil solar calendar, corresponding roughly to November-December in the Gregorian calendar. It falls in the cool season (hemanta) after the northeast monsoon rains — a time when the nights are long, clear, and lit with a particular clarity, making the festival of lamps (dīpas) visually magnificent.
The central festival of Kārttikai month is Kārttikai Dīpam — celebrated on the full moon day of Kārttikai when the moon coincides with the Kārttika nakṣatra. On this night, Hindus (Vaiṣṇavas and Śaivas alike, for this festival transcends sectarian boundaries) light countless oil lamps outside their homes, on the streets, on temple walls and towers, and in the temple tanks. The Bhāgavata Purāṇa and Śkanda Purāṇa glorify Kārttika month observances, describing it as one of the most meritorious months for Viṣṇu-worship. In Śrī Vaiṣṇava temples, Kārttikai Dīpam is celebrated with special alaṅkāra (divine ornamentation) — the deity is adorned with lamp-themed decorations, the temple is lit with oil lamps on every wall and pillar, and a great lamp (mahā-dīpa) is lit on the gopuram (temple tower), visible from miles around. Throughout the month, special evening (sandhi) services and night (thiruvanṭādi recitation) services are offered.
In Śrī Vaiṣṇava theology, the Kārttikai Dīpam connects to Bhagavān's nature as the source of all light. The Bhagavad Gītā (15.12) declares: 'the light in the sun that illuminates the entire world, the light in the moon and fire — know that as My light.' Bhagavān is the jyotiṣām jyoti — 'the light of all lights' — and the festival of lamps is the community's celebration of this truth: by lighting one lamp and then another from it (the tradition of lighting lamps from a single sacred flame), the worshippers re-enact how all the lights of the world are kindled from the single divine light of Bhagavān. The Āzhvār pāsurams of the Divya Prabandham invoke the theme of Bhagavān as light — particularly Nammāzhvār's Tiruvāymozhi passages where Bhagavān is called 'mā jyoti' (the great light) — and these are recited during Kārttikai month utsavams.