PRADOSHAM

Although many have written about PRADOSHA, I am giving my version of PARADOSHA herein.
The Meaning of PRA + DOSHA is removal of SIN.
There are FOUR TYPES OF PRADOSHAM.
(1) This is the common PRADOSHAM on all days. This occurs every day for ONE AND A HALF HOURS before sun set time at each place till SUN SET TIME.
(2) The second type of PRADOSHAM which is slightly higher than the first type, occurs twice a month on THRAYODASHI DAY of FULL MOON and NEW MOON i.e SHUKLA PAKSHA and NYOONA PAKSHA. To make it clear it occurs on the 13th day of (கறுத்த பக்ஷம், வெளுத்த பக்ஷம், കറുത്ത പക്ഷം, വെളുത്ത പക്ഷം) of every month before one and a half hour of sun set till the time of sunset of each time zone.
(3) There are two more types of PADOSHAM which are superior to these two which occurs on SATURDAYS and MONDAYS provided the THITHI, THRAYODASHI falls on such days. They are called SANI PRADOSHAM and SOMA PRADOSHAM respectively. SATURN is supposed to be the ruler of KARMA and the importance is that Lord Shiva has more influence over Saturn on SATUR DAYS and can cause Saturn to loosen or release entirely some of the karmic bonds that limit us. It is also thought that the first Pradosham was on a Saturday and observing this time transports us back to time of the Churning of the Milky Ocean.
MONDAYS, are ruled by Lord Shiva’s consort, the Goddess Parvati who rules over the Moon. The Moon rules emotions and emotions influence thought. Karma is created by thought.
THE GREATNESS OF PRADOSHA POOJA
Pradhosha pooja is one of the most important among the poojas performed to the Graceful Lord Shiva. In Shukla Paksha trayodasi (thirteenth moon day) between 4.30 p.m. to 6.00 p.m. is called Pradhosha. It comes once in fifteen moon days. Pradhosha time is especially meant for praying Lord Shiva. Praying in that time will free us from out sins and gives moksha finally (hence the name Pradhosha). During pradoSha time a special type of circumambulating called SOMA SUTHRA PRADIKHANAM is performed
THE MYTHOLOGICAL STORY OF PRADOSHA
Once Devas and Asuras using the serpent Vasuki and the hill Mandhara were trying to get Amrutham (nector) from the Kseerabthi (milk ocean). Then the terrible poison Halahalam came up. All got frightened and pleaded to Lord Shiva for rescue. Being the peak of mercy Lord Shiva ate that poison. Then as per His order they resumed their effort to get Amrutham. They got it on Dhwadhasi (twelfth moon day). Without praying and thanking the God, by whose help they got Amrutham ( THE NECTOR) , Devas started dancing and celebrating their victory.
On the Thrayodhasi Day (thirteenth moon day) they realised their sin for not praying the God and pleaded for forgiveness. Lord SHIVA is known for his immediate anger and forgiveness. Hence He forgave them and danced between the horns of the Nandhi (Holy bull). That time is called Pradhosham. Whoever prays Lord Shiva in that time, Lord Shiva fulfills their wishes and give them mukthi.
During Prodhosha time anointing (Abhishekam) LORD Shiva with the following is considered fruitful.

Milk gives long life
Ghee gives Moksha state
Curd gives good children
Honey gives melodious voice
Rice powder frees from debts
Sugar cane juice gives good health
Panjamrutham gives wealth
Lemon removes fear of death
Sugar removes enmity
Tender coconut gives enjoyment
Cooked Rice(Annam) gives majestic life
Sandal gives Lakshmi's grace

(For Pooja Manthras see the web.)