Once Janmjaya, the son of Parikshit, the scion of the Pandavas, asked Sage Vedavyas: “O great sage, kindly enlighten me about the method of worship of Bhagavati Devi.”
Sage Vedavyas said, “Although Devi can be worshipped at all times, there are auspicious periods prescribed in the scriptures for such. These periods are known as Nau Raatri, which is observed twice a year: in the month of Chaitra (March-April) and in Aashvin (September-October). The latter nine-day Nau Raatri commences with the new moon of the month Aashvin and terminates with Mahaa Navami, i.e. the ninth lunar day of the bright half of the month. During these nine days, devotees fast and Devi is worshipped in the forms of Durgaa, Kaali, Lakshmi and Saraswati. Offerings of dhaar can be made daily. For more austere sacrifice, it is recommended that they sleep on the ground. A ghee-deeya is kept alight before a picture or murti of Devi.” Also, devotees read and/or listen to Devi stotras, mantras and excerpts from Devi Bhaagvat Puraana.
