Dakshinayana or Pitrayana is the nighttime of gods in Hinduism and it lasts for six months or till Makar Sankranti. Uttarayana period starts with Makar Sankranti and it is the daytime of Devas. A human year is equal to one day of gods in Hindu religion. Dakshinayana is also the southern transit of Sun and nights are longer during this period. In 2011, Dakshinayana starts on June 21 for calendars followed in North India. For calendars followed in South India, Dakshinayana begins on July 16, 2011.
In Tamil Nadu, the month Aadi marks the beginning of Dakshinayana. There is also a belief that Lord Vishnu goes to sleep during this period and the Ekadasi just before Karka Sankranti is referred as Deva Sayani Ekadashi.
There are two methods followed in calculating the movement of the sun. In Drika Siddhanta method Dakshinayana starts when sayana sun enters cancer and this method is followed by some regional calendars. In this system, Dakshinayana begins on June 21, 2011.
But majority of Hindus in
follow the Nirayana System and in it Dakshinayana starts when ‘nirayana surya’ enters cancer. In this system Dakshinayana starts on July 16, 2011 and Uttarayana on January 14 or 15, 2012. South India