By the mythological story it is said that there was a princess who observed this fast of Alta Taddi Nomu whole day without water until she see the moon at night, but due to weakness she got fainted as she was not used to have fast. After knowing this incident her brother managed to show her a fake moon, by tilting the mirror to the fire and told her sister to break the fast. After some years she grew up and her brother started finding a suitable match for her beloved sister but in spite of their so possible attempts they could not find a young match for her, owing to which they finally settled her marriage with an old aged person. As soon as she knew about this she got upset as she had full belief that after performing Atla Taddi Nomu she must get a suitable match for her life, due to which she just left to the jungle and refused for the marriage. There she sat under a banyan tree and started praying to his Almighty, watching this Lord Shiva and Parvati came and told her the real story of the fast that she had performed. She went back and performed this auspicious fast with great consciousness and dedication. Soon they found a young and handsome partner for the princess. After this incident this festival is performed by every married woman.
The name suggest that Atlu means 'Dosas' and Taddi means 'Tadiya'( 3rd day), on the third day of Ashwiyuja month the moon is in wanning phase. Some necessary ritual that has to be performed by the women are like performing the fast by herself only, one has to take complete head bath, food has to be eaten before sunrise and fast has to be observed by all through the day without drinking water, fast can only be broken until the moon is seen it is mandatory and lastly the prayer and rituals are to be performed in the name of Goddess Gauri. During the fast 10 women are invited in the house and some basic ritual related to dosas, Dakshina or money, black beads or Nalla Pusalu, Lakka Jollu or Pasupu and Kum Kum, Tambulam.