Manasa Devi Puja, dedicated to Snake Goddess, also known as Nag Panchami, is observed mainly in Bengal, Jharkhand, Assam and parts of Orissa on various days in the Bengali months of Ashar, Shraban and Bhadrapad (June - September). Manasa Devi Puja 2017 dates are July 13 and July 27. Mansa Devi is the serpent goddess and is believed to be the daughter of Lord Shiva.
The rituals are also known as Manasa Devi Ashtang Puja. The rituals associated with the pujas are held on the fifth day or Panchami day of all fortnights in the month of Ashara and Shraban.
There are numerous rituals associated with Manasa Devi. From simple prayers to rituals which many might consider as grotesque.
Manasa is the goddess of snakes and fertility. She fulfills the wishes and protects one against snakebite. Associated with the earth and higher knowledge, she is worshiped mostly in eastern
. She is also propitiated by those not having children for an early child birth. India
Special murtis of Manasa devi are prepared during the period and worshipped.
You can find more details of Manasa Devi Puja in this earlier article.