Today, 27 September 2012 is Pradosh Vrat. It is referred to as Guru Pradosh (Brihaspati Pradosh) as it falls on Guruvara (Thursday).
This Pradosh falls on Shukla Paksha Dwadasi in Bhadrapad Month in Kannada, Telugu, Marathi & Gujarati and all other North Indian Hindi calendars.
This Brihaspati Pradosh falls in Purattasi Masam in Tamil calendar and in Kanni 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.