Papanasini Dwadasi is observed when Pushya Nakshatra falls on the Dwadasi Tithi in Hindu lunar calendar during the waxing phase of moon. It is then also known as Jaya Dwadasi, Sukrata Dwadasi and also Pushya Nakshatra Yukt Mahadwadashi.
Such a combination is a very rare occurrence in a year in a Hindu Lunar Calendar.
The popular belief is that observing Papanasini Dwadasi is equal to observing 1000 ekadasis.
Papanasini Dwadasi is dedicated to Vishnu.