Navratri is a festival of Goddess Durga. This nine day festival honours the nine goddess of Navratri. Each of the nine goddesses of Navratri is an avatar of Shakti. Navratri is a festival that marks Maa Durga's fight with the deviant asura, Mahishasura and her glorious victory. It comes twice every year.
Right now we are celebrating the Vasant navratri which is the original time of Navratri. Lord Rama did an untimely puja of the nine goddesses of Navratri in October before attacking Ravana. The Navratri that comes later in the year is the more popular one now. However, the festival of Vasant Navratri is the actual tribute to the nine goddesses or avatars of Maa Shakti.
Here are the nine goddesses who are worshiped on the nine days of Navratri.
Day 1: Shailputri Mata
Shailputri is the part of goddess that was born as the daughter of the mountain king Himavant (or the Himalaya). She is also known as Parvati, a name that comes from 'parvat' which is the Sanskrit word for mountains. Goddess Parvati was Sati in her previous birth.
Day 2: Brahmacharini Mata
On the second day of the Navratri festival, goddess Durga is worshiped in the form of 'Uma' or Brahmacharini. This is the avatar of the goddess in which she performs 'tapa' or deep penance to reach the ultimate truth.
Day 3: Chandraghanta Mata
On the third day, Maa Durga appears as 'Sherawali' mata or Chandraghanta. This is a popular avatar of Durga that is worshiped in Vaishno Devi.
Day 4: Kushmanda Mata
Kushmanda Mata is one of the nine goddesses of Navratri. She sits atop a growling lion and holds 7 types of weapons in her 8 hands.
Day 5: Skanda Mata
The 5th goddess of Navratri holds her son named 'Skanda' in her arms. She is a goddess who comes from the fire and is worshiped for gaining knowledge or wisdom.
Day 6: Katyayani Mata
The sage Katyayani prayed for years to Maa Durga to have her as his daughter. She granted his wish and was born as the sage's daughter by the banks of the Yamuna river. Later she married Lord Krishna.
Day 7: Kalratri Mata
This avatar of goddess Durga is dark as moonless night and hence the is name 'Kalratri'. She rides a donkey and her hair is left open in a dishevelled way. Mata Kalratri is a protector of mankind and destroyer of the Dark forces.
Day 8: Maha Gauri Mata
Maha Gouri is a household goddess. She blesses the family with peace, food and prosperity. She rides a bull and is often dressed in white.
Day 9: Siddhidatri Mata
Siddhidatri is the ultimate form of Shakti or the 'female goddess' who is worshiped by all other gods. Mata Siddidatri has achieved all the 8 siddhis and is thus half the body of Lord Shiva. When we see Lord Shiva in the Ardhnareshwar avatar, half his body is comprised by Mata Siddhidatri.
These are the 9 forms of the goddess worshipped during Navratri.