Rathasaptami is a vedic festival dedicated to Soorya (the Sun). The Sun turns his Ratha (Chariot) drawn by his seven splendid horses with Aruna the charioteer in a north-easterly direction, it also heralds the change of season to spring. It is said that from this day the Sun would ride the chariot properly making day and night equal. The festival falls on Magha Shudha Saptami (Magha masa Shukla paksha Saptami tithi).
It is believed that Soorya (the Sun) was born to Rishi Kashyapa and Aditi on this day and started enlightening the world on this day. This day is celebrated to show our gratitude to Soorya who is the source of life, the nurturer, and the soul of beings.
The Sun is worshipped chanting mantra and offering water (Argya) early in the morning, during Arunodaya. Aruna is charioteer who comes before sunrise. Doing Soorya Namaskara (Sun Salutation) in the early morning is also one of the rituals on Rathasaptami. Some people keep fast on this day. Sweet dish is prepared to offer god.