Usually the yearly ritual of offer of water oblations to the departed souls is done
on the thithi they died.
But there are other occasions too when this ritual is done.
Varaha Purana lists these occasions.
In the chapter on
THE APPROPRIATE TIME FOR PERFORMING SHRADDH (Varaha purana)
Markandeya tells Gurumukh
the auspicious times for performing the rituals of shraddh,
"A person desirous of performing the rituals of 'kamya shraddh' can do so on any of the following days-
a) at the commencement of uttarayan or dakshinayan.
b)at the time when vyatipat yoga takes place.
c) at the time when vishu yoga occurs.
d) during both solar and lunar eclipses.
e) if troubled by the evil influences of a constellation or a planet.
f) if troubled by nightmares.
g)at the time when the Sun changes it's position from one zodiac to another.
It is to be noted here that barring the two occasions
(troubled by evil influences and nightmares),
all the other occasions are connected with the Sun's movement or position.
The commencement of uttarayan or dakshinayan denote the two edges of entry and exit points.
The vyatipat yoga denotes a point on space traveled by both the sun and the moon
which is found to enable pithrus receive the offerings.
(The details of this distance is given in Surya Siddhantha)
The vishu yoga denotes the equinox (equal day and night)
which occurs at the entry of the Sun in Aries in the uttarayan
and at the entry of the sun in Libra in dakshinayan.
The solar and lunar eclipses are the times
when the sun and the moon come on the same plane with the earth.
In all these instances, the Sun's position is the determinant.
To know why the sun acts as the determinant
for enabling the pithrus receive the oblations,
we must first know the kind of role played by the Sun everyday.
The sun plays a major role in two activities that have been ordained
to be done by everyone in daily life.
In Kali yuga, there is no restriction on anyone depending on caste, to do these. (1)
Faith and commitment only are needed.
These two are sandhyavandhana (the worship of sandhya or twilight) and agni hothra.
(1) During sandhyavandana, the sun receives the arghya offered.
(for the question from Yaksha why the sun rises and sets everyday,
Yudhishtra replied that it is to receive the arghya )
(2) Agni hotra is done at two times of the day, namely, the sun rise and sunset.
The sun adds strength to agnihotra at these 2 times, i.e., at twilight (2)
The time of the day is very important in both these occasions,
namely exactly at the twilight time (sandhya kaalam).
( It must be remembered that sun is associated with two wifes, Sandhya and Chaaya.
The oldest existing temple on Sun in India is in Martand
in the south of Anantnag district of Kashmir valley
which was originally known as the Valley of Piris and Rishis.
This temple now in ruins and
not yet under the protection of Archeological department was once known as “Surya Theerth”,
a place of pilgrimage for Hindus.
The local lore further confirms that it was here Rishis of yore worshiped everyday
Sun and Sandhya (twilight) and Chaaya (shadow) whose temples are also found nearby.
The architecture of this temple looks different from the known and existing ones
making us wonder whether there were exclusive rules and rituals to worship Sun.
The association of sandhya and chaaya shows that these two are of significance,
metaphysically and scientifically.)
Sandhya is twilight.
Is there any significance attached to twilight?
The following has been reported at space.com some time ago.
There is a bright green, thin ray of light
emitted from the Sun's north and south pole
exactly at the twilight of earth timing,
which scientists are still not clear of the reasons.
(The sandhya manthra of Rik vedins glorifies the 'green' seen everywhere at twilight)
Since twilight is continuously happening throughout the earth,
this light must be emitted from the poles of the sun continuously,
though it is visible on the earth only in that part of the twilight region.
The important role of the Sun at twilight has been confirmed in research on agni hotra
which was undertaken when it was found
that two families who were doing agnihotra and were keeping the agni alive by offerings into it,
when the poisonous gas leaked from Union carbide plant at Bhopal,
were the only ones who remained unaffected amidst the heaps of those who succumbed to the gas.
In the research it was found that time mattered most.
It takes approximately 90 seconds for the disc of sun to disappear / appear at the horizon of earth.
The agnihotra done exactly at this time yielded the results
which was of the nature of strengthening the air in an area of 30 sq metre against any pollution or harmful radiation.
(This bears relevance to Gitacharyan’s vachan (3)
that He has created Brahma deva onwards with yajna (sacrifice)
and for the sake of mutual benefits with devas.
If you nourish the devas, the devas will nourish you in turn. (4)
This is usually rediculed by the ignorant.
But what happens has been proved scientifically by agnihotra.
The benefit of agnihotra is that
the fume released into the air cleanses the air of poisonous substances
and fresh nutrients are injected into the air.
In this yajna or worship or homa of Agnihotra,
the doer nourishs the Vayu deva.
The Vayu deva (air) in turn nourishes the doer
by the air which is now made healthy
Bhagawad Gita further says
that if a man lives without these yajnas,
then he is a thief or sinner. (5)
In the case of air, we constantly extract norishment from the air.
In return we do not replenish for the drawal made
by means of agnihotra.
If a person takes without giving back
then he can be aptly called as a theif
or a sinner.
That is the import of the Gita vachan.
Agnihotra is something now we have known.
But similar drawal are happening with reference to all the other natural elements.
When a pay-bak or replenishment is not happening,
that leads to imbalance
or in-equilibrium of that element.
The result of this is that
the 'deva' of that element can not bestow the boons on us
instead it will 'curse' us.
This curse is in the form of
disease or lack of strength.
This is the natural sequence of non worship (no-yajna)
of that Devatha!)
This scenario ( about twilight) can be put in other words.
When the sun’s polar regions appear or disappear from our sight,
something is radiated from them.
(1) This happens everyday at sun rise and sun set when we are supposed
to offer arghyam in sandhya vandhanam and rice into Agni hotra fire.
(2) This also happens when another celestial body,
namely the moon crosses the sun’s disc as happens in a solar eclipse.
The crossing of the sun happens (symbolically) on all amavasyas.
But the moon is not exactly crossing the disc of the sun on amavasya,
but crossing the path of the ray of that greenish light
that emerges from the poles at sometime during amavasya.
These are the occasions when tarpaNam is done.
There is a similarity between TarpaNam and sandhya vanadhana
in another way.
That is about the 'water'.
In sandhyavandhana water is used as 'arghyam' (offering).
In tarpaNam too water is offered.
The differences are with reference to whom this water is offered.
In sandhya vandhana done at twilight,
the purpose of offering water is to kill the 'demons' that may afflict the doer.
In tarpaNam the water is given as food along with sesame seeds.
The water of same physical and chemical description
is capable of doing two different functions.
How this is possible can be best understood
by reading the following link.
Scientific research has shown that water carries whatever one thinks.
If one thinks of a lotus, the water molecules take up the shape of a lotus.
Similarly the thoughts and aspirations also are found to enter the water.
This link tells more about what happens to water used in
different types of kriyas we do - in the rituals, including kumba theertham in a homa.
Water as carrier or transporter can be understood well
if we look at the way ‘dattham’ (act of giving) is done.
Usually water is offered when a person gives something to the other.
When king Janaka gave the hand of Sita to Rama in their marriage,
the kanyadhaan manthras of giving her
were accompanied with slow-pouring of water.
The water carried the message and transported it -
that is the import.
That water is the carrier and transporter can also be understood
if we relate it to
why Rama chose Sarayu to reach His abode,
why the Released soul crosses Viraja river which seems to transport it to Vaikuntham,
why arghyam is given to the Sun god
and why water is given in tarpaNam to pithrus.
(It is also to be noted that in all near death experiences reported,
those who have come back,
have narrated either having seen a Light at the end of a tunnel
or a waterway or waterfall which seemed to carry them along.)
Coming back to the present topic, the water offered as arghyam
and water used in tarpaNAm acquire some significance
only when the sun’s polar regions appear or disappear.
The justification for this is entirely from our observation.
We have always noticed that while doing agnihotra
(as guided by volunteers who spanned throughout India in the early 90s with information and the materials such as copper kundam etc)
a particular bird, which till today we are not able to identify,
used to make a peculiar note when the sun exactly rises and sets.
The timing is so exact, that we have stopped looking at the clock
while preparing the agni and waiting for the exact twilight time to offer rice into it.
This note has not been heard at any other time of the day.
BUT we used to hear the same note of that bird when the solar eclipse exactly begins!
This makes me wonder whether the condition that is present at sunset (or sun rise) is again present when the eclipse begins.
(did this play a deceptive role in KurukshEthra war?
The kauravas would not have exactly seen the sun disappear below the horizon.
In a war field the atmosphere must have been hazy.
They would have depended on different symptoms such as bird’s note, as we have noticed, and thought that twilight has set.)
From our age-old practices,
it is understood that a such condition happening everyday ( at sandhya)
helps in carrying out agni hotra and sandhyavandanam
and that happening at eclipse,
-helps in a rarer kriya, that of offering tarpaNam.
Since the grahana kaalam is known as punya kaalam,
we understand that it is not a polluted kaalam as we tend to believe,
due to austerities like abstinence from food and placing darbhai for protection.
These are like managing small inconveniences, while in reality,
a big opportunity is produced to enable those who have
to reduce their ‘pithru-kadan’ by offering tarpaNam.
During lunar eclipse,
the polar rays of the sun reaching the twilight zone of the moon,
which is but the edges of Full moon, are obstructed by the earth,
thereby bringing some contact to that part of earth,
though on night side, with the polar rays of the sun.
Then that part becomes conducive for getting into a link
with pithru lokam through the tarpaNam offered.
The timing of tarpaNam during eclipses,
like soon after the beginning or after starting to leave etc
can thus be related to the obstruction to polar rays of the sun by moon or earth.
(1) Sargam 74, Utthara khanda of Ramayana by Valmiki.
(2) "Adithya hrudhayam" - 'yEsha chaiva agni hotram vha balam chaiva agni hotriNaam.'
(3) Bhagawad Gita 3-10
(4) Bhagawad Gita 3-11
(5) Bhagawad Gita 3-12 & 13