Panchak is observed during the transition of Sun from Kumbha rashi (Aquarius) to Meena rashi (Pisces). In September 2013, there will one Panchak. Panchak begins on September 17 and ends on 21st September. It starts at 9.32 AM on 17th and ends at 5.09 PM on 21st September, 2013.
It is Shukla Paksha Trayodashi in Bhadrapad month to Krishna Paksha Dwitiya in Ashwin Month as per North Indian Hindi calendar. It falls between Bhadrapada Shukla Paksha Trayodashi and ends on Dwitiya during Krishna Paksha of Bhadrapdaa Month according to Marathi & Gujarati calendars.
Dhanista, Shatbhishak, Purva Bhadrapada, Uttara Bhadrapada & Revati Nakshatras are considered as Panchak Nakshatras. During Panchak, auspicious programs like vivah, grih pravesh, upanayan, aksharabhyasa, etc. are avoided.