Chhath is a very ancient Hindu Vedic festival. Chhath puja is dedicated to Hindu God Sun and Chhathi Maiya (Vedic Goddess). It is celebrated mostly in Bihar and some other Northern states of India and madhesi state of Nepal.
Chhath puja is observed to thank Hindu god Sun that gives energy to sustain life on earth. In Hindu religion, it is believed that worshipping God Sun will help cure certain diseases that include leprosy. Surya (God Sun) is also worshipped for attaining blessings of longevity and prosperity for the family members.
Chhathi Maiya: Chhathi Maiya is called Usha in Vedas and is believed to be younger sister of sun God. The festival celebrates rising sun as well as setting sun.
Sandhya Arghya: On the third day, prashad is prepared and vratins along with family members go to apond or any large water body where they worship the setting sun.The prashad includes Puri (deep-fried puffs of wheat flour), rice pudding and bananas. Chhathi Maiya songs are sung and stories related to the Chhath are recited. The fast is believed to bless mothers who do not have their child.
The fast is also observed to pray for the longevity of one's child.
Shubh muhrat to pay offerings on this Sandhya Arghya is till 5:29 in the evening while on the final day the arghya to the rising sun can be offered till 6:31 in the morning.
Also read: Importance of the four days of festival