Saptami Vrata is observed during the waning and waxing phase of the moon in a traditional Hindu calendar. The day falls on the seventh day after Purnima and Amavasi. Important Saptami Vratas are observed in the Magh, Poush, Phalguna and Bhadrapad months. Lord Surya (Sun God) is worshipped on the day.
It is believed that those who observe Saptami Vrata in Magha and Bhadrapad month will be untouched by grief, will attain materialistic gains and will gain Moksha in the next life.
Worship of Surya on the Saptami day in Poush month will help in redeeming (washing away all the sins).
Huge importance is attributed to the Saptami Vrata observed during the waning phase of the moon in Magha month. This is known as Surya Jayanti or Magh Saptami or Rath Saptami. It is considered highly beneficial and those who observe the Vrat will be blessed with a child.
Another important Saptami Vrat is observed during the waning phase of moon in Phalguna month and it is known as Nanda Vrata and is believed to help in attaining eternal joy.