The significance of Navratri is much more than just worshiping the nine forms of Maa Parvati, Maa Lakshmi and Maa Saraswati and the symbolism of Victory over Evil.
As per astronomy and Vedic Astrology the earth undergoes two major Sun operations in a year and the seasons are dependent on the direction of the Sun's movement. Once when the sun appears to move southward of the equator (Dakshinayan), the intensity of the Sun is not that harsh and the environment is full of moisture the second is when the Sun appears to move northward, the sun rays are more intense and the environment is more of a dry kind.
The first signifies the onset of winters and the second signifies the coming of summers.
This time when two seasons combine the human body becomes more prone to diseases as it is less resistant, both physically and mentally, to the attack of foreign body like micro organism, bacteria and viruses.
The first union of two seasons comes in Chaitra Masa Shukla Paksha Prathama to Navmi (March end to mid April) known as Ram Navmi and the second one comes in Asvin Masa Shukla Paksha Prathma to Navmi (any where in October month) known as Durga Navmi.
The segregation of months and days, to tap these unions, is done with the help of astrology and then adopting Ayruveda and other remedial measures to combat the possible disease is the deep buried significance in celebrating the Navratris.
All the nine days of the Navratri, different Goddesses are worshiped to protect the individual from falling prey to the possible traps as indicated in his horoscope.The first three days Goddess Parvati, ( who is the lord of Rahu and with her positive energy the negativity of Rahu is minimised) in her different forms is wordhipped. The next three days Goddess Laxmi (who is the Lord of Venus, which can bestow the native all earthly comforts) in her different forms is worshipped and the last three days Goddess Saraswati (who bestows the native with knowledge) in her different is worshipped.
Let's see how it effects the native who worships these goddesses, with proper procedures, in their different forms in the Navrtras.
1st Durga--- Shailaputri---The Mooladhar Chakra gets awake in the worshipper and if the horoscope has any sign of ailment that sign diminishes.
2nd Durga--- Bharmacharini---By worshipping this form of Goddess Parvati, the human develops the intent of sacrifice, tapa, good moral and the mind does not sway away from the dutiful path. However is one's mind weak as per the horoscope, it gets strengthened by worshipping on this day.
3rd Durga--- Chandraganta--- By worshipping this form of Goddess Parvati, the Manipur Chakra awakes in the worshipper. The worldly problems faced by the individual are greatly reduced.
4th Durga--- Kushmanda----- By worshipping this form of Goddess Lakshmi, the worshipper is bestowed with the boon of long and trouble free life and the ills depicted in ones horoscope gets depleted as the Anahat Chakra in him awakes.
5th Durga--- SkandaMata--- By worshipping this form of Goddess Lakshmi, the worshipper is bestowed with awaking of Vishudh Chakra, by virtue of which the ultimate calm and peace is restored in him.
6th Durga--- Katyayani---By worshipping this form of Goddess Lakshmi, the worshipper is bestowed with awaking of Agya Chakra and any ill effects of the likes of diseases, agony, danger, imperfection as seems possible in his horoscope, vanish for good from the life of individual.
7th Durga--- Kaalratri--- By worshipping this form of Goddess Saraswati, the worshipper is bestowed with awaking of Bhanu Chakra and the ill effects caused due to diseases get permanently over.
8th Durga--- Mahagauri--- By worshipping this form of Goddess Saraswati, the worshipper is bestowed with awaking of Som Chakra and the impossible yoga, not visible in the horoscope, seems possible.
9th Durga---Shiddhidatri----- By worshipping this form of Goddess Saraswati, the worshipper is bestowed with special siddhi by virtue of which nothing seems inaccessible.
If the worshipper worships the above forms of Durga by following the right rituals, all the ill, dangers and shortcomings as inscribed in his horoscope wane away.