Manasa, also Manasa Devi,is a goddess of snakes, worshipped mainly in Bengal and other parts of northeastern India, chiefly for the prevention and cure of snakebite and also for fertility and prosperity. Manasa is the mother of Astika, sister of Vasuki, king of Nāgas (snakes) and wife of sage Jaratkaru (Jagatkaru).
Manasa Puja is an authentic form of Deity worship described in the Vedic scriptures. It entails worshiping of the Deity in mind.
Manasa Puja is the next step to physical ritual of Puja performed by people. We have a two types of puja, Nitya puja (daily/continuous) (Includes Sandhya Vandanam and puja to the family deity) and Naimittika Puja (Occasional/situational) (Includes celebration of specific important dates like festivals etc).