Srividya is called Chandrakala Vidya or Kundalini Vidya. That is the Science of Srividya is related to the waxing of the Moon. Just as the Moon that is physically present in the sky, the same moon is reflected in the Sahasrara Chakra of the individual. Concept of Time (Kaala) is the product of Kameswara and Kameswari.
These 15 days are the same for Bright Lunar Fortnight (Sukla Paksha) and Dark Lunar Fortnight (Krishna Paksha). The 15 Devatas in Bright Lunar Fortnight recur in the Dark Lunar Fortnight for the corresponding day which iscalled Tithi. Apart from these 15 dieties, there is one more Devi which is the 16th Devi among these Tithi Nitya Devatas. This 16th Devi is called Shodasi. This Shodasi shines with 16 dimensions on Pournami (the 15th day of Bright Lunar Fortnight) and the same Shodasi shines with 1 dimension on Amavaasya (the 15th day of Dark Lunar Fortnight).
The concept of Time is expressed in terms of 1 year in Veda. 1 year is expressed in terms of 12 months. And 12months are expressed in terms of 360 days. Each month is represented with 2 fortnights of Moon (Bright and Dark). Hence, the entire concept of time in the form of 1 year is presided by these 16 tithi nitya devatas.
These 360 days are the 360 degrees of Time. These 360 days or 360 degrees are the 360 Rashmis or Rays that the emanations from Lalitha Tripurasundari. And hence, the Time which consists of 360 degrees in the form of 360 emanations of Devi is in control of Lalitha.
It is to be noted that all these 360 emanations start at Muladhara Chakra and culminate at Ajna Chakra. So, the Lalitha Tripurasundari which is of the form of Kameswara and Kameswari sporting at Sahasrara Chakra is untouched by the time which stops at Ajna Chakra.
So, the concept of time in the form of 30 days and 12 months are the product of Shiva with this 16th dimension concept called Shodasi. This Shodasi is called Nitya or Dhruva or Sada. IfPanchadashakshari Mantra of Srividya represents the 15 dimensions of the Moon then Shodashakshari Mantra represent this 16th Dimension of the Moon. This Shodasi of 16 dimensions is ever united with Shiva.
The image of the moon at the crown of Shiva is this 16th Dimension of Shodasi that we see in the pictures of Shiva. The Mantra of this 16th Dimension is SRIM Bija. This is suffixed to the Panchadashakshari mantra and that becomes Shodashakshari. And hence, Shiva is called 17th Dimension because He holds back all the 16
Dimensions of the Moon.
Sri Jnaneshwar Maharaj, a great shaktha of Natha School, in his work "Amritanubhava" addresses the Shiva with 17 Dimensions.
Now, the entire cosmos is the product of Matrika in the form of 16 vowels and 34 consonants. These 16 tithi nitya devatas or deities that I mentioned above represent the 16 vowels from A to Aha (visarga). `A' vowel is Shiva and its combines with the 16th Dimension called Shodasi and gives rise to rest of the vowels and consonants.
They are 50 in number and thus they are called Shaktha Pitas (Refer Lalitha Sahasraranama "Panchashat Peetasupini). These 50 letters are presided by respective Dieties called Yoginis. These 50 yoginis in the form of 50 letters represent the garland of rosary having 50 beads in the hands of Mother. These 50 letters represent the garland of 50 skulls that adorn the breast of Kali.
But on the Amaavasya or the 15th day of Dark Lunar Fortnight, only 16th dimension shines forth in the form of Nitya Devata. So, they cannot invoke the rest of the deities and ask for the nectar for the performance of abhisheka ritual.
Moreover, the IDA and PINGALA nerves that are the subtle nervous centres called Nadis are in union with each at the Mooladhara Chakra (remember IDA and PINGALA are the SUN and MOON that come in one line during the New Moon Day of Dark Fortnight).
Hence, SAMAYACHARIS donot worship the Devi on New Moon Day because there is no Ambrosia or Nectar for them to perform the ritual to Shodasi (this is purely internal worship at Sahasrara). The Tantra or the Mode of Worship adopted by them is called Dakshinachara Path.
Their Plane of Divine consciousness during the union of Ida and Pingala is symbolically represented as Graveyard because their body consciousness is Zero ie., Dead to the External World. Then the worship starts for them which is called "Kula Ritual". The tantra adopted by these is called Vamachara.
Whatever the path the aspirant follows, there are certain basic requisites for the Sadhana to be successful. The Goddess of Srividya is the Mother of Beauty and Bliss, the Mother of Love and Grace.
One who follows the path of Srividya should be a worshipper of beauty and grace. He should reject ugliness in all its forms. He should not only shun the outer ugliness but also ugliness in thought, word and deed.
power of Vishnu is called Sri, the auspicious one. She is the beautiful one. She gives both bhoga and moksha. If you go with desire to Her, She will blend your spiritual progress with material glitter which is imitation jewellery. She shows Herself and Her true riches to the one who is dispassionate, and approaches Her with divine oneness.
When the Sri beeja is added at the end of Panchadasi, it becomes what is known as laghu shodasi. She is ever radiant and charming like a sixteen year old girl.
Tripura Sundari is an ocean of knowledge. She cannot be exhausted even if one were to write a million volumes about Her. The best thing to do is then do Her upâsana as She directs it.
The best form of upasana is to seek the source of knowledge as an observer; by not running away from bondages; by not being attached to the results of actions, but by acting out of divine will. This is the triple combination of bhakti, jnana, and karma margâs.
We will continue Tripura Sundari upâsana in Her own words: The more you know, the more you love, the more you experience OM.