Thiruvathirai or Arudhra Darisanam is celebrated in the South Indian state of Kerala and Tamil nadu. Thiruvathirai(Arudhra) in Tamil means "sacred big wave", using which this universe was created by Lord Shiva about 132 trillion years ago. Chidambaram in Tamil Nadu, the Sri Natarajar temple's annual Festival, is celebrated on this date.
 
 
It takes place on the full moon night in the Tamil month of Margazhi (December–January) and this is also the longest night in a year. Literary and historical evidence in the form of stone inscriptions state that the festival has been celebrated on this day for more than 1500 years. Lord Siva is praised in Tamil by many names, one of them is Athiraiyan (ஆதிரையன் ), from Thiruvathirai (Thiru + Athirai).
 
Tamil hymns of Manikkavacakar's Thiruvasagam (particularly the hymns Thiruvempavai and Thiruppalliezhuchi) are chanted in temples instead of Sanskrit mantras. On the very day of Thiruvathirai the idols of Nataraj (Lord Siva) and his consort Sivakami (Parvati) are taken out of the temple premises for a grand procession. It is one of the major events in almost all the Siva temples in Tamil Nadu.
 
Sambandar sung in Tevaram during 7th-9th century, how Thiruvathirai celebrated at Kabaleesharam (present day Mylapore, Chennai).
 
 
"ஊர்திரை வேலை யுலாவும் உயர்மலைக்
கூர்தரு வேல்வல்லார் கோற்றங் கோள் சேரிதனில்
கார்தரு சோலைக் கபாலீச்சரம் அமர்ந்தான்
ஆதிரைநாள் காணாதே போதியார் பூம்பாவாய்"
 
Appar wrote a separate pathigam (10 songs) in Tevaram, in the name Thiruvathirai Pathigam which describes the importance and celebrations of Thiruvathirai.
 
In 4th Tirumurai he sang about the celebration in Tiruvarur
 
 
"முத்து விதான மணிப்பொற் கவரி முறையாலே
பக்தர்க ளோடு பாவையர் சூழப் பலிப்பின்னே
வித்தகக் கோல வெண்டலை மாலை விரதிகள்
அத்தனாரூ ராதிரை நாளா லதுவண்ணம்"
 
The cosmic dance of Lord Siva represents five activities – Creation, Protection, Destruction, Embodiment and Release. In essence, it represents the continuous cycle of creation and destruction. This cosmic dance takes place in every particle and is the source of all energy. Arudra Darshan[16] celebrates this ecstatic dance of Lord Siva.
 
It is essentially a Saivite festival and celebrates the cosmic dance of Lord Siva, which is represented by the Nataraja form. Arudhra (Thiruvathirai in Tamil) signifies the golden red flame and Siva performs the dance in the form this red-flamed light. Lord Siva is supposed to be incarnated in the form of Lord Nataraja during the Arudra Darshan day.
 
Most of the temples around the world with Lord Nataraja and Siva as deity perform the Arudhra Darshan. Neivedhyam (food for God) made for Lord Nataraja on that day is Thiruvathirai Kali.
 
The festival is celebrated by Sri Lankan Tamils at Thinnapuram Sundareswarar Temple, it is called Eezhathu Chidambaram.
 
 
Thiruvadirai or Thiruvempavai Nonbu
Significance in Tamil Nadu
 
In Tamil Nadu, the unmarried women will fast during the day time. They will take food before sunrise and start their fasting. They will break the fast after witnessing the moon rise. Nonbu (fasting) starts nine days before and ends on Thiruvathirai day so totatlly they fast for ten days.
 
There is special food called Thiruvadhirai kali made of rice, jaggery, moong dhall, coconut, cardoman and ghee with Thiruvathirai ezhlu curry koottu, which is made out of seven vegetables, that is cooked and served on this day. They choose from pooshanikai (pumpkin), paranghikai (ash gourd), vazhakkai (plantain), pacha mochai (field beans), sarkaraivalli kizhangu (sweet potato), cheppan kizhangu (colocasia), urulai kizhangu (potato), katharikai (eggplant) etc.
 
The dancing form of Lord Siva is taken out on procession from all Siva temples in Tamil Nadu. In Chidabaram, The night before the full moon, Abishekam, or holy shower, to the Lord Siva is performed with the nine most precious gems (navarathnam), including diamonds, coral, pearls, jade and emerald, among others. On the day of full moon, the chariot procession takes place. The most important Arudhra Darshan festival takes place at the Chidambaram Siva Temple in Tamil Nadu. The cosmic dance of Lord Siva is enacted on the day.
 
 
When observed
 
ska.ndha purANam describes about this vratam. When the sun shines in the dhanur rAsi that is in the month of mArkazi, in the day of thiruvAdhirai for which rudra is the devata this vratam is observed.
 
Way of observing
 
In the morning of thiruvAdhirai one gets up early in the morning and salutes the Dancing Lord. After bathing goes to the abode of Lord siva and there worshiping the Lord by abhishekam and offerings, lights up the ghee lamps to illuminate the abode. Fasting for the whole day, the next day saluting the Three-eyed Lord serving food for the devotees one has the food.
 
Glory
 
munychakEchar, vyAgrapAdhar and the serpant kArkOtakan observed this vratam and saw the blissful dance of the Lord. Saint vyagra pAdhar got austerous upamanyu as his son. A brahman called vipular observing this vratam went to kailash with the body by a splendid divine carrier and returned back. Later he got liberation. As the Lord is dancing blissfully and gracefully on this day this vratam is considered quite auspicious to please the God.