Every month, we have Shivaratri on the Chaturdashi of Krishna Paksha. Maha Shivaratri is the Shivaratri that occurs annually on the Chaturdashi of (Krishna Paksha) in the Tamil month of Masi (February-March).
It is the day Lord Shiva grants lots of blessings to His devotees and relieves them of their sins and of the cycle of birth and death.
This year, Maha Shivaratri falls on February 13, Tuesday.
There are 4 Phases of abhishekam for Shiva on the night of Maha Shivaratri.
It is the time of Lord Brahma doing Pooja to Shivalinga while taking the form of a swan to find out the top of Lord Shiva. Yellow coloured silk is the cloth to drape Linga during this Phase.
In the 2nd phase of Pooja, Lord Vishnu does pooja to Linga while taking the form of the boar to find out the bottom of Shivalinga. White silk is the cloth to drape Linga during this Phase. Santhanakappu is the special alankaram of this Phase.
During the 3rd phase, Goddess Sakthi does Pooja to Lord Shiva.This phase is called Lingothbava kaalam (the incident of Brahma in the form of swam and Vishnu in the form of boar going in search of the top and bottom of Shivalingaandbothof them doing Pooja to lord Shiva).
Red silk is the cloth to drape Linga during this Phase. Special alankaram is done with bel leaves and pachai karpooram.
During the 4th phase, all the animate beings in the Universe do pooja to Shiva. Special alankaram is done with kesar. Alankaram and Pooja to Linga are done in a grand manner during this Phase.