From my childhood I have been trying to understand how Moon came to be known as Chanda Mama and how this lori came into being. After 62 years of my life now I have understood the concept of this and I am sure you will agree.
What is the connection of Moon with the popular festival namely Bhai Dooj celebrated in the State of Haryana ,Uttar Pradesh ,Gujarat ,Maharashtra and Delhi. We know that this ceremony signifies the duty of a brother to protect his sisters well as sister’s blessings for her brother.
On the occasion of this festival either the married sisters visit the house of the brother or the brother /brothers visit the house to get blessings of the sister and exchange gifts. The far away sisters who can not visit the house being far away sends prayers for the long life of the brothers through the MOON GOD. She performs ARTI of the MOON . This is the reason why children of Hindu parents lovingly and affectionately call the moon CHANDA MAMA.(Chanda ….is Moon and Mama refers to Mother’s brother).
There are other legends such as Lord Krishna visit to his sister’s house Subhadra, after killing the demon Narakasur on the second day after Deepawali or Lord Yama (God of Death ) visiting the house of her sister Yamuna on the earth just one day after Deepawali and finding the house well lit as if in his honour . Since he had visited without any gift he asked his sister to express her WISH for some thing .Ultimately she insisted that on this day”All brothers should remember their sisters and visit them if they can and all sisters should pray for the happiness of their brother . This is how custom of Bhai Dooj came into practice.