Pradosha Kalam is the period of time during which Lord Shiva is known to have evolved out of the dizzy state (due to poison he had consumed) and performing Ananda Thandava on top of his Rishabha Vahana (Sacred Nandi Bull). During this pradosha time,Lord Shiva is expected to be in the most happiest of moods as he has been successful in saving the mankind of the ill effects of the Poison. He therefore performing Ananda Thandava blesses all the three world Thevathas as they pray to him.
Lord Shiva is known to be very generous with respect to giving away boon (Vardhan although, he would test his devotees to the core) praying him during Pradosha Kalam observing fast, performing puja, chanting of Rudram, visiting sacred places of interest is bound to bring prosperity and happiness in life.
Pradosha Kalam falls on the 13th lunar day of Trayodashee during the shukla and krishna pakshas, waxing and waning fortnights in the Hindu calendar months. If, from sunset to next sunrise is divided into 5 equal parts, the first part is called Pradosha Kalam and it denotes the end of day time and the beginning of night. This is also called the period of Asuras (Raaksha Neram). It is believed that each day of the week has different benefits during Pradosh time:
Sunday(Bhaanu Vaara Pradosha): Goodness To All (Mangalam to all) Monday(Indu Vaara Pradosha): Positive (perception) thinking Tuesday (Bhauma Vaara Pradosha): No Poverty (Prosperity to all) Wednesday(Saumya Vaara Pradosha): Blessing of child, Knowledge and education Thursday(Guru Vaara Pradosha): Divine blessings through the Pitru's, all dangers will be eliminated Friday(Bhrgu Vaara Pradosha): Nullifying (negativeness) opposition Saturday(Sthira Vaara Pradosha): Elevation (promotion) get back the lost wealth
Mahaa Pradosh Kalam comes yearly during the month of Maagh/Maashi (U’ma’ +’Shi’Va) before Mahaa Shiv Raatri. If the Mahaa Pradosha comes on Saturday, it is called Shani MahaA Pradosha. Saturday is the day when Lord Shiva swallowed poison and this is called Shani (Sthira in Samskritam) Pradosha. It is categorized into three categories of importance depending upon the month on which Pradosha falls:
(1) Uttama Sthira Pradosha - Maximum power - The Sthira Pradosha that comes during the months of Chaitra, Vaishaakh, Aashaadh and Kaartik during the Growing Lunar Cycle (Shukla Paksha), i.e from New to Full moon period.
(2) Madhyama Sthira Pradosha - Normal power - The Sthira Pradosha that comes during the months of Chaitra, Vaishaakh, Aashaadh and Kaartik during Diminishing Lunar Cycle (Krishn Paksha), ie Full to New moon period.
(3) Adhama Sthira Pradosha - Minimum power - All the other Sthira Pradosha. The Pradosh that falls on any Saturday is called MahaA Pradosha (Sthira Pradosh).