Kalaratri mata is the seventh aspect of Navadurga. Kaalratri is worshipped on seventh day during Durga Navaratri. In 2017, Kalaratri Puja date is September 27. Maha Saptami / Maha Ashtami (Durga Ashtami) is the day to worship the Goddess.
Spiritual importance of Kaalratri Navadurga Puja:
On the seventh day of Navratri, Yogis and other upasaks of Shakti concentrate their mind on Sahasrara Chakra. Kaladatri represents the Sahasrara Chakra which provides him all the siddhis and nidhis of the universe.
Kaaldatri puja makes the devotee free from this material world and provides him with Ashta siddhis and Nava nidhis. With this puja, all his sins and obstacles are completely vanished.
Dhyana Mantra of Kaalratri Navdurga:
Dhyana mantram of Kaalratri Navdurga is recited during the seventh day or Maha Saptami day during Navarathri. This mantra makes one free from his misfortune and keeps him fit to face any challenge in the life.