Popular Naganatha Swamy temple (Raghu's sthalam), Thirunageswaram

Naganatha Swamy temple, Tirunageswaram.Tamil Nadu.  Flicker
Raghu Kaalam  (also spelled as  Raghu kaal, Raukalam, ) or the  time dominated by  Raghu (one of the nine planets) is a  particular  period of time every day that is considered inauspicious for any new venture, wedding or religious ceremonies or family functions, according to Indian Vedic astrology. The Raghu shrine at Naganatha Sawmi temple near Kumbakonam, TN is famous for Raghu Kaala Puja to negate  Raghu Thosham (bad effects on humans). Hindus across India, in particular, south India will never venture to do good deeds during this period, fearing failure midway.
Naganatha Swamy temple, tirunageswaram, Tamil Nadu. Exploring My Life
  Thirunageswaram town of  Thanjavur district, Tamil Nadu state   has a popular temple dedicated to  Naganatha Swami (Naga in Tamil / Sanskrit meaning Snake and Natha meansing God). Naganatha is a form of Lord Shiva  and his consort Parvati is depicted  here as Piraisoodi Amman and she is  in thava kolam (in  deep penance). This place  is  8 km east of Kumbakonam, an important pilgrim center in South India and  is counted as one of the Navagraha temples for planet Rahu. It is also one of the most visited temples in the district.

The reason why this place assumes  religious importance in  Navagraha worship is there is a shrine  of  Rahu Bhagawan (one of the nine celestial bodies). Unlike other places of worship,  here he is seen  with his consorts.The mythological serpents Aadi Seshan, Dakshan and Kaarkotakan worshiped Shiva here

Every day when abishekam (bathing of the idol with milk) is preformed during the Raghu Kaalam on the stone idol of Raghu (Serpent), a mysterious thing occurs which one can't see in other shrines. The striking feature is  milk that is poured on the stone idol of Raghu  turns blue when it passes over the idol and once again becomes  white upon reaching the floor. Gautama Maharishi, Parashara and Bhageerata and king  Nala worshiped Shiva here. It is the 29th in the series of Tevaram  (7th century Tamil Saiva canonical work ) and is a Padal Pettra Stalams (one of the 276 temples) located south of the river Cauvery. 

Raghu deity , Tirunageswaram, Tamil Nadu. www.templeadvisor.com
The temple complex has four gopurams (towers) and houses many halls and shrines. The famous being the ornamental entrance hall   built during the  Nayak (Thanjavur based) period.The temple was built  by Aditya Chola I in the 10th century A.D. Later rulers made some  additions on their own.  The temple has a dimension  of 630 ft (190 m) South-North and 800 ft (240 m) East-West with  four major streets around the four sides. There are four gateways along the four sides with entry towers (gopuram) and a surrounding compound wall.  There are  Vinayaka shrine, Bali Peetam, Nandikeshwara hall and flag staff, etc  located in the eastern entrance. An interesting fact is the Ganapathy idol in the  shrine here is said to have been installed by the great saint Sadasiva Brahmendral along with a Ganapathy yantra.This is confirmed by an  inscription in the temple.
That many serpents kings like Adishesha, Takshaka and Karkotaka, worshiped Shiva at this place is the reason why this place is called  "Tirunageswaram".  As per Hindu legend, the king of snakes, Adisesha who did penace at this place, called Senbaranya Kshetram because of the presence of large number of Senbaga trees, received a boon from Lord Shiva. Goddesses  Girigujamba, Lakshmi, Saraswathi, Ganesha, Muruga, and Shasta worshiped lord Shiva here.  The main Goddess being  Swayambu  in the form of Meru, no abiskekam (anointing) is done on the idol. The temple, it is believed, is being guarded by "Maha Bhairava  and  is assisting the divine mother during her prayers.

 Hindu legend has  it the  Demi God Indra earned the curse of sage Gautama as he misbehaved with the saint's  wife Ahalya while he was away. In order to get relieved from the sage's curse, it is said, that Indra worshiped Giri-Gujambigai with a scented material termed Punugu for 45 days.  

The temple tank located in the southern side has a hundred pillared hall. The second precinct / prakaram  has the Rahu shrine in the north eastern corner. There is a hall / mantap decorated with Nayak style pillars with yalis along with nine horses on the east and south sides. It was built by Govinda Dikshitar, the minister of successive Nayak rulers, Achuthappa Nayak (1560–1614) and Raghunatha Nayak (1600–34) of Thanjavur. The  hall in the northern side with pillars decorated with yalis  is used for displaying idols (Utchavar)  during  festive occasions. The Dwarapalaga (Entry guards) images on each side at the entrance of Naganathar shrine are made of chunam clay (lime and clay mix) and not of stone.

Weekly rituals like somavaram and sukravaram, fortnightly rituals like pradosham and monthly festivals like amavasai (new moon day), kiruthigai, pournami (full moon day) and sathurthi are well attended by the people.

The major festival  are: The Brahmotsvam is held  for ten days in the Tamil month of Karthigai (November–December). As per local legend, Rahu got relieved of his pains praying to Naganathar during a Shivaratri day and the day is celebrated in the temple. Navarathri festival is celebrated for nine days for Girigujambigai and the images of Naganathar and Girigujambigai is taken in horse chariot on Vijayadasami, the concluding day of the festival. Sekkizhar Vaikasi Pooja is celebrated from 1969 on the birth date of Sekkizhar, the author of Periya Puranam.  Rahu Peyarchi is yet another major  festival celebrated once every 1.5 years on the star when Rahu switches its planetary position from one raasi (galaxy) to the other.
The temple has six Kala Puja at various times from 5:30 a.m. to 10 p.m., and twelve yearly festivals on its calendar.