Today, 27 October 2012 is Pradosh Vrat (Shani Pradosha Pujan). It is referred to as Shani Pradosh as it falls on Shanivara (Saturday).
This Pradosh falls on Shukla Paksha in Ashwin Month as per all North Indian Hindi calendars and the Panchangams followed in Maharashtra, Gujarat, Andhra Pradesh and Karnataka.
This Shani Pradosh falls in Aippasi Masam in Tamil calendar and in Tula Masam of Malayalam calendar.
Pradosh Puja time is 4.30 to 6’0 clock in the evening. Pradosha Astakam is an auspicious prayer chanted during Pradosh Shiv Pujan.
As Trayodasi also coincides with Pradosh, it is considered highly auspicious and celebrated as Shani Trayodasi.