Kataka Sankramana, or Karkataka Sankramana, is the Dakshinayana Punya Kala. A year in Hindu calendar is divided into two halves or Ayanas. In 2015, Kataka Sankramana begins on July 17 and in some places in South India, Shraddha and Tarpana is performed on this day. One half is known as Uttarayana (January to July) and the other Dakshinayana (July to January). Uttarayana is considered to be the daytime of Devas (gods) and Dakshinayana is the nighttime. In science, Kataka Sankramana is the progress of Sun (Surya) to the south of the equator.
North India, Karkataka Sankramana is known as Karka Sankranti. Is this period inauspicious? It is not.
In Tamil Nadu, the Aadi month begins with Dakshinayana and no auspicious events are held as it is the first month during the nighttime of Devas. But numerous pujas including the Varalakshmi Pooja takes place in this month so there are many people who believe it is not inauspicious.
In North, the four most auspicious months or Chatur Mas happens during Karka Sankranti period.
Kataka Sankramana Shraddha and Tarpana are done by Hindus on this day in
South India. It is a ritual dedicated to the dead family members.