Tamil Calendar (Panchangam)

Puthandu (Tamil New Year, Chithirai 1st), Chithirai Thiruvizha (Meenakshi Thirukalyanam at Madurai – 10-day temple festival celebrating the divine marriage of Meenakshi and Sundareshwarar)

Vaikasi Visakam (Lord Murugan's birthday – celebrated with grand processions at Palani, Thiruchendur, and all Murugan temples), Agni Nakshatram begins (peak summer heat period)

Aani Thirumanjanam (grand abhishekam of Lord Nataraja at Chidambaram – one of the most important temple events in Tamil Nadu)

Aadi Perukku (18th of Aadi – river festival celebrating monsoon abundance), Aadi Pooram (Andal's incarnation day), Aadi Fridays (Amman worship)

Avani Avittam (sacred thread ceremony renewal for Brahmins – Upakarma), Krishna Jayanthi (Gokulashtami), Vinayakar Chaturthi

Purattasi Saturdays (strict vegetarian observance and Vishnu/Perumal worship for all 4 Saturdays), Navaratri and Vijayadashami (Golu/Kolu display of dolls)

Deepavali (Diwali – celebrated on Amavasya of Aippasi), Skanda Sashti (6-day fast honoring Lord Murugan's victory over Surapadman)

Karthigai Deepam (festival of lights – massive flame lit atop Tiruvannamalai hill, homes lit with rows of oil lamps), Subramanya Sashti

Thiruppavai/Thiruvempavai (30-day dawn devotional singing), Vaikunta Ekadashi (Paramapada Vasal opening at Vishnu temples), Arudra Darshanam (Nataraja's cosmic dance celebration)

Thai Pongal (4-day harvest festival – Bhogi, Surya Pongal, Mattu Pongal, Kaanum Pongal), Thai Poosam (Lord Murugan – Kavadi offerings at Batu Caves and Palani)

Masi Magam (sacred bathing in the sea when Moon is in Magha nakshatra – major event at Mahabalipuram and Pondicherry), Maha Shivaratri

Panguni Uthiram (divine marriages celebrated at major temples – Srirangam, Tirupati, Madurai; associated with Uttara Phalguni nakshatra)

Bhogi falls on the last day of Mārgazhi. Households “discard old possessions” and light a bonfire to burn the heaps of discards before dawn. In the Kongunadu belt around Coimbatore the Kaappu Kattu ritual ties protective neem and palm leaves above the entrance. Madras households dispose of broken furniture and old clothes into the street bonfire and re-whitewash exterior walls.

Marks the start of the auspicious Thai month and the Sun’s turn northward (uttarāyaṇa under the sidereal reckoning). New rice from the just-completed harvest is boiled with milk and jaggery in a clay pot in the open courtyard; the moment the mixture boils over, the family shouts “Pongalō Pongal!” Decorations include kolam with sugarcane stalks, turmeric plants tied to the pot, and offerings to the Sun at dawn. Chettinad households serve sakkarai pongal (sweet) and venn pongal (savoury, with pepper and cumin) on banana leaves.

Honours cattle — “mattu” means cow/bull. Animals are washed, their horns painted and decorated with shining metal caps, multi-coloured beads, tinkling bells, sheaves of corn and flower garlands. In southern Tamil Nadu, especially the Madurai–Tiruchirappalli–Thanjavur–Tirunelveli–Ramanathapuram belt, this is the day of Jallikattu (“ēru taḻuvuṭal” — bull-embracing — attested in Sangam literature, c. 400–100 BCE) at famed venues like Alanganallur, Avaniyapuram, and Palamedu.

“Kaanum” means “to see/visit”. Young people visit elders for blessings, families pack leftover Pongal into picnic baskets and gather on river banks or beach fronts. Chennai’s Marina and Madurai’s Vaigai banks see lakhs of visitors. In Telangana-bordering districts the day is observed as Kanum Pongal — kanu = “to see” — with girls offering leftover rice to crows in the “kaaka padaippu” ritual.

The pivotal Drik figure. The Kerala-school mathematician who, after a sustained programme of his own eclipse observations, found that the parameters in use since Āryabhaṭa had drifted noticeably from the sky. His Dṛggaṇita (“computed by observation”) was composed in 1431 CE with corrected planetary mean motions and equation-of-centre terms. Parameśvara was the disciple of Mādhava of Sangamagrāma, founder of the Kerala school whose infinite-series work would centuries later prefigure the Newton–Leibniz calculus.

The first Indian Fellow of the Royal Astronomical Society and the first Indian to publish modern astronomical discoveries — the variable star R Reticuli (1867), made from the Madras Observatory under N. R. Pogson. Chary came from a family of hereditary Tamil panchangam-compilers and grew unhappy about the errors in the traditional pañcāṅga — Vakya-computed positions were off the observed sky by minutes of arc, occasionally a full degree, on slow planets. During the 1870s he published a Drigganita-pañcāṅga in Tamil and Telugu built on observed planetary parameters. His son Chinthamani Raghava Chary carried on the work.

Founder in 1883 of the Pambu Panchangam — the most influential commercial Tamil almanac, now producing roughly 300,000 copies per year from Chennai. The name comes from the cover illustration of a snake (pambu) encircling 27 nakshatra-circles — the snake symbolising the wandering, near-elliptical lunar path. Modern editions are labelled “Suddha Vakya Panchangam,” confirming the Vakya lineage.

Under his pontificate the Kanchi Kamakoti Peetham’s own Madathu Panchangam shifted to Drik in 1952 — the highest-profile adoption of observational ephemerides by a major southern matha. The Sringeri Sharada Peetham and the Ranganathaswamy Temple at Srirangam meanwhile continued the Vākyapañcāṅga tradition, ensuring that both schools remain in continuous publication in the twenty-first century.