This is a slightly deeper topic. But it is also something that everyone should know. It would amaze us to learn how scientifically our sages arranged all this.
A human day is of 24 hours .Our Earth takes 1 day to rotate , and 365 days to revolve around the sun. Whereas the moon revolves around the Earth in one month and rotates by itself every day. That is why the moon can be seen in the same point everyday by the people on earth. It is said that Chandraloka, also known as Bhuvarloka, is the opposite side of the moon which we cannot see (explained in the article “Bali and Water”) . Amavasya is the day when the Sun and the Moon are at 90 degrees to the Earth. Ama means same place and Vasi means residing or connecting. Astrology recognizes the Sun as the ruler of life, and the Moon as the ruler of the mind. We know that the month of Karkadaka begins when the Sun rises in Karkadaka rashi. Similarly, Karkadaka is regarded as the Moon’s own shrine. Thus there is a direct connection between the Sun, the Moon and the Earth of Karkadaka Amavasya. This is just one aspect of it.
The six months from Makaram to Mithunam are known as Uttarayana and the six months from Karkadaka to Dhanu are known as Dakshinayana. One year of men is regarded as one day by Devas. Deva karmas are best performed during Uttarayanam, and pitru karmas are performed during Dakshinayanam. Then it becomes clear that the first Amavasya in Dakshinayana i.e, Karkadaka Amavasya has a lot of significance. Here is the second point.
Please take notice of the following.Amavasya is experienced by our Pitrus as daytime in Chandraloka or Bhuvarlok, which we cannot see. It means that our pitrus are awake at that time. Then it is believed on the day of Amavasya when we perform Bali, our Pitrus get it as an edible mid-day meal.
Above all this, there is another important thing to be mentioned. When Bali pooja is performed on Amavasi, there is a presence of divinity in it.Let me elaborate.
During the Sun’s Dakshinayana (i.e, from karkadaka to dhanu) the day of Thulavishu rises towards the Equator.
The equator represents the horizon of the northern poles or of the Devas. It is believed that then during the later days, Devas miss the sunrise. In other words, it’s night for the Devas at that time. Then Uttarayanam begins and the night of Devas extends until Mesha Vishu (six months for humans) which crosses the equator and reaches the northern hemisphere.
So the Vishu which comes in the month of medam is important because it is regarded as the start of the day for the Devas.
From this time to Thulavishnu i.e, six months later, is the time of day for the devas. Just as we experience midday even during the mornings, Devas experience midday in Karkadaka which comes 3 months after medam month.
Devas and the Pitrus experience midday during Karuthavavu of karkadaka. Therefore, it is certain that there is also the presence of Devas while providing food for the pitrus. Ramayanamasacharana is also held during this month because it is the midday time for the devas.
Let me conclude by saying one more thing.A month of human beings is the equivalent of a day of our pitru.
As a part of it ,Krishna Paksha from pournami to Amavasya is experienced as day by Pitrus and Shukla Paksha from Amavasya to Pournami as night. Pournami paves way for the spiritual development of humans towards God. Amavasya depicts total devotion or submission to God.
Every pooja depicts an absolute dedication towards God. Thus Amavasya becomes the day of dedication, be it for the Devas or the Pitrus. Especially the Karkadaka Amavasi.
Poojari Manoj K Viswanathan