... Interesting thing you wrote about souls way hanging in the air after body death. Latvians have similar tradition regaling death souls. Latvians are doing this in october, put various food on the table in outside and staying for souls of dead people. This period last`s about month. ....
ybrao a donkey
Click to go to http://www.sanskrit.org/www/Samskaras/ancestors6.html. I quote from the above web page:
Hindu Funeral Rites and Ancestor Worship 
Antyesti, Sraddha and Tarpana
6. Another Form of Sraddha
I will conclude this article by mentioning a final variation to the sraddha process, which is based on the ancient Pancaratra tradition whose influence can be readily seen in the Mahabharata some of the Puranas.
A follower of Visnu is enjoined to perform the sraddha rites with the remnants of food first offered to Visnu. The Padma-purana enjoins that deities other than Visnu and the fathers may be propitiated with food that has been first offered to Visnu. In that same text Narada says, "Following the ordinances of the Sattvata School, the devotees first worshiped Visnu, the God of gods, and with the remnants of such food worshiped the fathers." In the Brahmanda-purana it is enjoined that the father's remain gratified for thousands of kalpas with rice cakes mixed with sacred blossoms of tulasi, prepared with the remnants of food offered with devotion to Visnu. In the Skanda-purana, Siva says, "Food should first be offered to Visnu and then the very same food should be distributed to the minor deities and the fathers." In the Purusottama-khanda of that same text, it is stated, "For avoiding defilement, the remnants of food offered to Visnu should be mixed with the rice cakes to be offered to the fathers. Food is rendered pure when sprinkled with the waters of the tulasi and when mixed with the food offered to Visnu." In the course of a conversation between Brahma and Narada it has been made clear that the worship of Visnu alone is capable of releasing the fathers from the suffering of hell." It is even stated that the performance of the sraddha rite is useless in the age of Kali without first worshipping Visnu.
This series of quotations from various Puranas reflects the Pancaratrika idea that through a person's sole reliance on Visnu all things that a human being would otherwise have to do alone could be accomplished through the grace of God. The successful outcome of the sraddha process was therefore, not dependant on the power of the ritual, the expertise of the priest, precise timing, and availability of the articles, etc. but upon God alone. This approach involved the 'handing over' of the fate of the soul to God.
According to this approach, food or water that is offered to the pitrs is first offered to Visnu and thereby transformed into visnu-prasada. The word prasada means "mercy" or "grace." Thus visnu-prasada is God's grace. This prasada of Visnu is then offered to the pitrs, who now receive God's grace instead of mere food or water. In this way, the grace of God has the power to elevate and sustain the pitrs in a manner that no human power can match. In the case of a homa or havan, a ritual performed with fire, the fire is used as the "delivery system" by which Visnu is first offered food. This food offering, which is now God's grace, is then offered to the pitrs through the fire. It is thus Agnideva, the fire God, who acts as the link between this world and the world of the pitrs.
Psychologically this approach to the sraddha process is very satisfying to grieving family members. The invocation of God's grace to reach beyond human endeavor is indeed powerful. Copyright © Sanskrit Religions Institute 2003. All rights reserved.
Walker, Benjamin. Hindu World, An Encyclopedic Survey of Hinduism. In two volumes. New Delhi: Indus, 1968.
Shastri, Dakshina Ranjan. Origin and Development of the Rituals of Ancestor Worship in India. Bookland Private: Calcutta, 1963.
Saraswati, Swami Dayanand, translation by Vaidyanath Shastri. The Sanskar Vidhi. Sarvadeshik Arya Pratinidhi Sabha: New Delhi, 1985.
 The Pancaratra Agamas claim to be based on the Sukla-yajur-veda (which is no longer extant) and purports to be of Vedic origin. The Pancaratra Agamas are extremely voluminous. The number of texts is in the hundreds, but the most ancient and authoritative Pancaratra texts are the Sattvata, Pauskara and Jayakhya Samhitas.
In India, pitri-paksha (ancestor-worship-fortnight) is observed during the dark-half of lunar month AsvAyuja (asvin). This usually comes in October. The first nine days of the white-fortnight of this lunar month aSvin are used for worshipping nine Goddesses, (mAte in lATvia). That means after mAte worship you will have pitara worship.
The month kArtika which follows the dark-fortnight, is also dedicated to ancestors (pitris also called pitaras similar to father and paternal in English.). Oil lamps are lit at doorsteps of houses, intended to show the way to pitaras in darkness. kArtika month (usually October-November) is important both from the point of ancestor worship and viShn worship. You can observe the importance of vishN in the above quote.
15 dark days in Asvin + 30 days of kArtik will give 45 days, which is equal to a month in lATvian calendar.
The month following kArtika, called 'mArgaSira' (from Lamda Orion) is also important for vishN worship. viShn (krishNa) in bhagavadgita chose to say that he was the month mArgaSirsha among the 12 months.
10/35 mAsAnAm mArgaSirshoo aham rutuunaam kusumAkara.
One word of caution: Feeding ancestors need not be viewed as something despicable or barbarically superstitious. Whether it is God worship (dEva yagnam), Ancestor worship (pitru yagnam), Guest worship (atidhi pUja), rishi yagnam (worship of sages), suvAsini pUja (worship of housewives), all these are done on a one-to-one basis.
What a European/American host does when a guest rings the bell of his apartment?
Answer: Open door.
Invite with some sweet words. (AavAhayAmi).
Inquire whether everybody is happy on the other side (guest's family, friends).
Give some water to wash feet. (arghyam, pAdyam).
Offer a towel. (vastram).
Offer water to drink.(udakam).
Offer some tiffin (madhuparkam).
Offer some Coffee. (pAnIyam).
Invite them to have a bath. (snAnam)
Offer Towel again.
Offer some clothes if necessary.(vastram).
Offer some cosmetics, incenses.(pushpam, dhupam, nIrAjanam).
Offer some food.(naivEdyam).
Offer some water intermittantly.(madhya madhya udaka pAnE).
Offer some betel leaves and nuts.(tAmbUlam).
So on so forth.
Finally take him to the gate of the apartment Complex or to the end of the street, to bid farewell; if necessary, helping to hire a car; Or drop in host's own car.
The Hindu chants of worship contain nothing but the above formalities, uttered using the Sanskrit language. They appear bizarre, because most Hindus do not learn Sanskrit. These are called ShODaSOpacArams or 16 steps of duties of a host, receiving his guest.
In fact, there was a Hindu custom prevalent upto the end of 19th Century. A householder should not dine his lunch alone without a guest also dining beside him. This guest should not be somebody who is already known to him. That means the householder has to search for strangers everyday to dine with him, with all the ShODaSOpacArams listed above. This practice was very convenient in those days, when there were no hotels where people could buy food. People had to walk long distance, when visiting other places for reaching relatives, or on business or on pilgrimage. So if a person starts walking at dawn, walks around 15-20km. by midday, to reach a village, he would be welcome with open hands for dining. No need to search for hotels.
The best example for guest worship can be seen in the book manucaritra-svArOcisha manusambhavam. telugu language. poet allasAni peddana. period of writing: Early 16th Century CE. In the story, the protagonist pravara welcomed and hosted a pilgrim. Their conversation is very captivating, delightful, enchanting, fulfilling and soothing to readers' minds.
Here is a link to the part of the manucaritra story, which depicts guest worship.
click to see english translation of guest worship story, which is very interesting.
Thus atithii/s (guests), by definition, were those who visit without tithi (date) i.e. without prior information. Ancestors are also like atithis i.e. guests, who deserve worship.
Hence ancestor worship need not be shunned down upon, unless it is taken to extremities of whims and fancies.
These are our bad days of "kali". We must have wads of currencies in our wallet, and carry some ATM cards, Credit Cards, if we have to survive on journeys.
Of course, every system has its own advantages and disadvantages.