Somasutra is the structure for the water passage that is installed on the north side wall of the Sanctum Sanctorum. The main purpose of this structure is to channel Abhishekam water that comes from the deity present in Garbhagriha.
Installing this structure is a must for a temple as per the Agama shastras. The passage that is present to the side of Shivalingam to the panavattam is also referred as Somasutram. It is also called with several other names like Pranalam, Gomukham, and Jala nirgama nalam.
What you need to know about Somasutram
During ancient times, Somasutra used to be a very long, narrow structure to simply carry the abhisheka jala or the water used in the rituals. The later constructed temples adopted to have a shorter one with a water passage opening on the ground.
Somasutra can be present in various shapes, it can simply be a straight plain structure or with few designs. It can also be replaced with the heads of Nandi, or as of passage coming out of lions mouth.
As per some Shaivagamas and Shilpashastras, the water coming from the pranalam must fall or pass on the statue of Chandeshvara. But many temples have the Chandeshvara statue installed beside them.
All the temples, Shaivaite, Vishanavite or the Saktha have the Somasutra. But it is usually a plain structure in Vaishnava Temples.
But in the Shaiva temples, it can be an elongated structure with Chandeshvara or Chandesha statue or else as a Gomukha, the cow faced one. In Shakta temples it can be an elongated structure or with a face of a lion.
Somasutra has a lot of importance that is the reason why the stoned used for the construction of the mula virat is the same stone type that is used in the construction of Somasutra.
One can take the water or panchamritas that comes out of it showing it to Chandikeshwara as a Prasada.
Also touching this water passages tip and then touching the center of the head region is believed to lead to the path that awakens Sahasrara chakra, the crown chakra of Kundalini.
Somasutra plates are the pooja items that have the passage to drain the water. It is mostly used for doing Abhishekam inside the home. One can find a variety of Somasutra plates in various materials like gold, silver, copper, and bronze as well as in various sizes.
One can even find somasutra plates engraved with mandalas, chakras, and yantras on them.
These plates are the replicas of the panavattam of Shiva Lingam.
Somasutra Pradakshina or Chandeshvara Pradaskshina
In temples of God Shiva, one should not cross the somasutram while doing the circumambulation and is strictly restricted as per the Agamas that one should not cross it.
This Pradakshinam is said to be the most suggested way to do the Circumambulation in temples dedicated to God Shiva.
Pradakshina in the shiva temples have importance and is not performed by rotating around the temple. But it is done in a peculiar way. That pradakshina is called Somasutra pradakshina, Chandeshvara Pradakshina, or sometimes called Chanda or Chandi Pradakshina.
In this Pradakshina one needs to start from the Balipeetam and Dwajasthambam areas and do pradakshina moving in the clockwise direction till the Somasutram and come back till the chandeshvara statue that is present near the Somasutra. If the Candeshvara statue is not present in the temple then you can do it near the water falling place.
Then return back clockwise till Somasutra and then anticlockwise to Chandeeswara statue and in the third circumambulation stop near the Balipeetam and bow to the lingam and enter into the main temple.
Doing the Pradakshina, is believed to give immense punya.