Shivaratri comes once in a month just the night before every new moon day. The night is dedicated to Sadhana (sacred practice) that puts the Sadhak (practitioner) on the path of realizing the truth about oneself and the universal self.
And the Sadhak is expected to reach a culmination point of his or her year-long Sadhana, an upward milestone on the path, on the night of Maha Shivaratri.
Maha Shivaratri falls on the night before the new moon day ending the month of Magha and beginning of Palguna on Hindu calendars.
Right from the Vedic age, the ancient Indians had placed a high importance on self knowledge. Unlike rishis, who dedicated their entire life to gain this knowledge, others needed to be engaged in myriad other tasks to keep the wheel of life rolling. But the wise didn’t want them to be left behind in the pursuit of higher knowledge. They prescribed the night before new moon day for their Sadhana as total absence of celestial light would be most conducive for the inward journey.
Month after month, ordinary folks kept themselves away from all kinds of indulgence and focused their mind on Shiva, the god of destroyer of distinctions, or the lord of the principle of oneness. And on the night of Maha Shivaratri, or the great night of Shiva, they sought to experience the merging of their individual self with the universal self, Shivoham or ‘I am Shiva’ knowledge.
Over time, as the appetite for higher knowledge was on the wane, observations began to get more and more symbolic, but more and more celebratory. And Shiva too appeared in many formations. Now though few observe Shivaratri that occurs every month, many people go on a fast, and keep themselves awake in the night by gathering in Shiva temples or other places marked to celebrate Maha Shivaratri, listening to Vedic chanting and devotional songs.