Among the many unique scientific treatises of the Hindus there is one more named as Pancha-Pakshi Sastram. This forms a portion of the Hindu astronomical science. Twenty-seven forms of constellations are recognized by the Hindu astrologers in the moon`s path. Each is called a lunar mansion and in each of which the moon happens to be each day. These lunar mansions are considered to be of great practical consequence from their good or evil influence by the astrologers. And this is calculated not only at the time of birth of an individual but also during his lifetime. The situation of the moon in this or that Nakshatram at the moment is considered to regulate the occurring of an event affecting the individual concerned. Every person is born with his special star, mansion or Nakshatram. He or she can be called by whatever name in which the moon was at the moment of his or her birth. The Nakshatrams, are a source of infinite terror to the Hindus of all castes. They are consulted at births and marriages and in all times of difficulty, sickness and so on. Days and events become lucky or unlucky according to the decision of these mansions.

It is not possible to say when these twenty-seven stars, which are in the moon`s path, were created. But they are Kalpam after Kalpam i.e. several great ages along with other objects of creation destroyed, recreated, maintained for the next Kalpam, and again destroyed. The objects of creation are not quite the same at the beginning of each Kalpam. This is because of the fact that the good and bad actions outstanding against each object of creation. But in the case of the permanent devatas who do not return to the earth after their stay in Swarga i.e. heaven as the result of the good deeds is over, the fresh creation is quite the same at the beginning of each Kalpam. Every constellation, whether it is a fixed star or a planet, is a spherical body and it has a deity, which looks after it. The spherical body or Mandalam as it is called, is inanimate. While the deity, which has charge of, it has a soul and is subject to the orders of the supreme deity. The orders of the minor deity are also important under whose command they are placed. All the spherical bodies including the earth attract each other, and move in harmony in perfect accordance with the rules laid down by the supreme deity in Vedas and also in astrology. It is this attraction that constitutes the influence, which the fixed stars and planets exercise over the living objects on the earth, and the nature of each influence is described in astrology. Astrology is part of Vedas and every person who has faith in the Vedas must place faith in astrology. The Vedas are intended to reveal truths, which human reason cannot discover, and which must therefore be accepted without questioning. No cross-examination should be directed against those truths. Implicit faith must be placed on Vedic revelations.

These Nakshatrams or lunar mansions are grouped under five birds. And the names can be mentioned as the hawk, the owl, the crow, cock and the peacock. Hence each individual has not only his own Nakshatram but also his own bird out of these five. These birds are said to be in any one of the five states, namely: Eating, Walking, Ruling, Sleeping and Dying during the five watches or divisions of twelve hours of both the night and day time of each day of the week. Further, these states vary in the dark fortnight from what they were during the week days of the bright fortnight.

Most auspicious time for going on a voyage or a journey, for commencing, agricultural operations, for advancing against enemies, for going to ask favours of persons in power, for purchases and sales and so on can be declared as when his or her bird is either eating or ruling. The next best time is when the bird is walking which state is not very good either. The hour in which his or her bird is either asleep or dying is the worst hour that could be selected for any good attempt and is generally considered to be the most inauspicious for any undertaking.

The arrangement of the state of the birds in the order of importance can be mentioned as ruling, eating, walking, sleeping and dying. Eating state is considered to be three-fourth important while walking has only half of the importance of the eating state. Sleeping state is considered to be half as important as walking state, while the dying bird is half of the sleeping one.

The table furnishing the bird under which, he or she is placed from the Nakshatram or lunar mansion is given in all the Panchangam of Indian calendar. It is comprised of five limbs. These can be mentioned as the tithi, the varam, the nakshatram, the yogam and the karanam. A man desiring prosperity pays attention to the Tithi. One desirous of long life understands everything about Varam or the days of the week. The Nakshatrams are resorted to for being freed from sins. The Yogam is intended for obtaining immunity from diseases whereas the Karanam is said to secure for the observer success in all undertakings. Hence it was that the recital of the Panchangam was in vogue in olden days.