Since you are expecting answer in detail. Here is the story from Yog Vasistha about out of body experience (or astral travel:::
Chapter 21 — Saraswati Explains the Practice of Meditation, Astral Travel*
Saraswati continues speaking to Leela:—
1 Soon after death occasions the lack of physical senses, the sight of the world appears to the soul as
if he were seeing it with open eyes when he was living.
2 Before him is presented the circle of the sky
and its sides with the cycle of its seasons and times. He is shown the deeds of his pious and mundane
acts, as if they were to continue to eternity.
3 Objects never before seen or thought of also offer
themselves to his view, like the sight of his own death in a dream, as if they were the prints in his
memory.
4 But the infinity of objects appearing in the empty sphere of the non-physical intellect is
mere illusion, and the baseless city of the world, like a castle in the sky, is only the creation of
imagination.
5 Memory of the past world makes it known to us. Therefore, the length of a kalpa age and the
shortness of a moment are only false impressions proceeding from the speed and slowness of our
thoughts.
6 Therefore knowledge based upon previous memories or otherwise is of two kinds, and things known
without their cause are attributed to Divine Intelligence.
7 We are also conscious of thoughts that we
have not thought of before in our minds, such as we often have in our dreams. Another may remind us
of our deceased parents, so we think of them.
8 Sometimes genius supersedes the province of memory,
as in the first creation or discovery of a thing, which afterwards is continued by its memory.
9 According to some, those visible worlds are said to have remained in their ideal state in the Divine
Mind. According to others, there were no pre-existent notions of these in the mind of God.
10 According to some others, the world manifested itself not from memory but by the power and will
of God. Still others maintain it to be the production of a sudden, fortuitous combination of intelligence
and atomic principles (kakataliya sanyoga).
1 1 Completely forgetting the world is called liberation. That cannot be had if consciousness is
attached to what is desirable or is averse to the undesirable.
1 2
It is difficult to effect an entire
negation of both one’s subjective and objective knowledge of his self and the existence of the outer
world. Yet nobody can be freed without the obliteration of both.
13 As the fallacy of taking a rope for a snake is not removed until the meaning of the word snake is
known to be inapplicable to the rope, so no one can have rest and peace of mind unless he is
convinced of the illusory nature of the world.
14 Even with that, a person who is at peace with himself
cannot be wholly at rest without divine knowledge because, even though he has rid himself of the
devil of worldliness, the ghost of his inner ignorance may overtake him.
15 The world is certainly a
monster in itself without the knowledge of its Author, but the difficulty of knowing the First Cause has
rendered it an impassable wilderness.
16 Leela said, “If memories are the cause of one’s reincarnation, then, O goddess, tell me what were
the causes of the birth of the brahmin couple, without the vestiges of their past memories?
17 The goddess replied:—
Know that Brahma the first progenitor of mankind, who was absolute in himself, did not retain anyvestige of his past memories in him.
18 The first born, who had nothing to remember of a prior birth,
was born in the lotus with his own intelligence (chaitanya) and not because of his memory.
19 The
Lord of Creatures being thus born by chance of his own genius or creative power, and without any
assignable cause or design on his part, reflected within himself, “Now I am become another and the
source of creation.”
2 0 Whatever is born of itself is like a nothing that was never produced at all, but remains as the
absolute intellect itself in the clouds (chinnabhas).
21 The Supreme Being is the sole cause of both
types of memories (those caused by vestiges of prior impressions, and those produced by prior
desires). Both conditions of cause and effect are combined in Him in the sphere of his consciousness.
22 Therefore our tranquility can only come from knowing that cause and effect are the same and that
the auxiliary cause is in Him.
2 3 Cause and effect are mere empty words of no significance because it is the recognition of the
Universal Consciousness that constitutes true wisdom.
24 Nothing seen in the physical world or known
in the mental or spiritual worlds is ever produced. Everything exists within the consciousness of
one’s own soul.
25 Leela said, “What a wonderful sight you have shown me, O goddess. It is as auspicious as morning
light and as brilliant as lightning.
2 6 Now goddess, please satisfy my curiosity until I become
thoroughly familiar with this knowledge through my intense application and study.
27 Kindly take me
to that that mountainous place where the brahmin couple, Vasishta and Arundhati, lived and show me
their house.”
28 The goddess replied:—
If you want to see that sight, you have to be immaculate. You must give up your personality and your
ego-sense and attain awareness of the unintelligible Consciousness within the soul.
29 Then you will
find yourself in an empty atmosphere situated in the sky that resembles the prospects of earthly men
and the apartments of the firmament (i.e., nothing).
30
In this state we shall be able to see them (the
field of another’s imagination) with all their possessions and without any obstruction. Otherwise this
body is a great barrier in the way of spiritual vision.
31 Leela said, “Tell me kindly, O goddess, the reason why do we not see the other world with these
eyes, or go there with these our bodies.”
32 The goddess replied:—
The reason is that you take the true future as false, and you believe the untrue present as true. These
worlds that are formless appear to your eyes as having forms, just like you see the form of a ring
when its substance is gold.
33 Gold, though fashioned into a circle, has no curve in it. The spirit of
God appearing in the form of the world is not the world itself.
34 The world is an emptiness full with
the spirit of God. Whatever is visible is like dust appearing to fly over the sea.
35 The ultimate substance of the world is all a false illusion. The true reality is the subjective Brahma
alone. Our guides in Vedanta philosophy and the conviction of our consciousness are evidence of this
truth. The believer in Brahma sees Brahma alone and no other anywhere. He looks to Brahma through
Brahma himself, as the creator and preserver of all, and whose nature includes all other attributes in
itself.
37 Brahma is known not only as the author of His work of the creation of worlds, but as existent
of himself without any causation or auxiliary causation.
38 The practice of meditation trains you to disregard all duality and variety and to rely only on one
unity. Until you are trained through your practice of meditation, you are barred from viewing Brahma
in his true light.
39 By constant practice of meditation, we become settled in this belief of unity, and
we rest in the Supreme Spirit.
40 Then we find our bodies to be an aerial substance that mixes with the
air, and at last, with these our mortal frames, we are able to come to the sight of Brahma.
41 Being
endowed with pure, enlightened and spiritual frames (astral or subtle bodies), like those of Brahma
and the gods, the holy saints are placed in some part of the divine essence.
42 Without the practice of meditation, you cannot approach God with your mortal frame. A soul sullied
by physical sensation can never see the image of God.
43
It is impossible for one to arrive at another’s
castle in the sky, when he is unable to see the castle in the sky that he himself imagined.
44 Therefore, give up your gross body and assume your light intellectual frame. Immerse yourself in
the practice of yoga so that you may see God face to face.
45
It is possible to labor and build castles in
the air. In the same way, it is possible through the practice of yoga, and in no other way, to behold
God, either with this body or without it.
46 Ever since the creation of this world (by the will of Brahma), there have been false conceptions of
its existence. It has been attributed to an eternal fate, niyati (by fatalists), and to an illusory power,
maya shakti (of Maya vadis).
47 Leela asked, “O goddess, you said that we both shall go to the abode of the brahmin couple, but I
ask you, how is that possible?
48
I am able to go there with the pure essence of my sentient soul. But
tell me, how will you who are pure intellect (chetas) go to that place?”
49 The goddess replied:—
I tell you lady, Divine Will is an aerial tree and its fruits are as unsubstantial as air, having no figure
or form or substance to them.
50 Whatever is formed by the will of God from the pure essence of His
intelligent nature is only a likeness of Himself and bears little difference from its original.
51 My body
is the same and I need not lay it aside. I find that place with my body like a breeze finds odors.
52 As
water mixes with water, fire with fire, and air with air, so does this spiritual body easily join with
any material form that it likes.
53 But a physical body cannot mix with an non-physical substance, nor
can a solid rock become the same as the idea of a hill.
5 4 Your body has its mental and spiritual parts. It has become physical because of its habitual
tendency towards the physical.
5 5 Your physical body becomes spiritual (ativahika) by leaning
towards spirituality, as in your sleep, your protracted meditation, and your unconsciousness to fancies
and reveries.
56 Your spiritual nature will return to your body when your earthly desires are lessened
and curbed within the mind.
57 Leela said, “Say goddess, what happens to the spiritual body after it has attained its compactnessby constant practice of yoga? Does it becomes indestructible or does it perish like all other finite
bodies?”
58 The goddess replied:—
Anything that exists is perishable and, of course, liable to death. But how can something die that is
nothing and is imperishable in its nature?
59 Again, once we realize the mistake of thinking a rope to
be a snake, the snake disappears of itself and no one mistakes the rope anymore.
60 Thus, as the true
knowledge of the rope removes the false conception of the snake in it, so the recognition of the
spiritual body dispels the misconception of its materiality.
61 All imagery is at an end when there is no
image at all, just like the art of carving statues must cease if there is no more stone.
62 We clearly see our bodies as full of the spirit of God. Your gross understanding keeps you from
seeing this.
63
In the beginning, when consciousness (chit) is engrossed with the imagination of the
mind, it loses sight of the One.
64 Leela asked, “But how can imagination trace out anything in that unity in which the divisions of time
and space and all things are lost in an undistinguishable mass?”
65 The goddess replied:—
Like the bracelet in gold, waves in water, the show of truth in dreams, and the appearance of castles
in the sky
66 all vanish upon an accurate perception, so the imaginary attributes of the unpredictable
God are all nothing whatever.
67 Just like there is no dust in the sky, no attribute or partial property
can be ascribed to God whose nature is indivisible and unimaginable, who is an unborn unity, tranquil
and all-pervading.
68 Whatever shines about us is the pure light of that Being who scatters His luster
all around like a transcendental gem.
69 Leela said, “If it is so at all times, then tell me, O goddess, how did we happen to fall into the error
of attributing duality and diversity to His nature?”
70 The goddess replied:—
It was your ignorance that for so long has led you to error. The natural bane of mankind is the absence
of reasoning, and it requires remedying by your attending to reason.
71 When reason takes the place of
ignorance, in a moment it introduces the light of knowledge in the soul instead of its former darkness.
72 As reason advances, your ignorance and your bondage to prejudice are put to flight. Then you have
an unobstructed liberation and pure understanding in this world.
73 As long as you remained without
reasoning on this subject, you were either sleeping or wandering in error.
74 Now your reason and liberation are awakened and the seeds for the suppression of your desires are
sown in your heart.
75 At first, the nature of this physical world was neither apparent to you nor you to
it. How long will you reside in it and what other desires have you here?
76 Withdraw your mind from
its thoughts of the viewer, the visible, and the vision of this world. Settle your mind on the idea of the
entire negation of all existence. Fix your meditation solely upon the Supreme Being and sit in a state
of unalterable unconsciousness.
77 When the seed of renunciation has taken root and germinated in
your heart, the sprouts of your likes and dislikes will be destroyed of themselves.
7 8 Then the
impression of the world will be utterly effaced from the mind and an unshaken anesthesia willovertake you all at once.
7 9 Remaining entranced in your abstract meditation, in process of time you will have a soul as
luminous as a star in the clear sky of heaven, free from the links of all causes and their effects for
evermore. >
Chapter 22 — Practice of Wisdom (Vijnana-Bhyasa)
1 The goddess continued:—
Objects seen in a dream prove to be false on being awaken. Similarly, belief in the reality of the body
becomes unfounded upon dissolution of our desires.
2 As a thing dreamt of disappears upon waking,
so does the waking body disappear in sleep, when desires lie dormant in the soul.
3 As our physical bodies awake after dreaming and desiring, so our spiritual bodies awake after we
cease to think of our physical states.
4
In deep sleep we are devoid of desires. Similarly, in the state
of renunciation, even though we are awake in our physical bodies, we have the tranquility of
liberation.
5 The desire of men liberated while living (jivan mukta) is not properly any desire at all. It
is a pure desire relating to universal wellbeing and happiness.
6 The sleep in which the will and wish are dormant is called deep sleep, but the dormancy of desires
in the waking state is known as unconsciousness to delusion (moha) or unconsciousness (murchha).
7 Again the deep sleep that is wholly devoid of desire is called the turiya or the fourth stage of yoga.
In the waking state it is called samadhi or union with Supreme.
8 The embodied man whose life is freed from all desires in this world is called the liberated while
living (jivan mukta), a state unknown to those who are not liberated.
9 When the mind becomes a pure
essence (as in samadhi) and its desires are weakened, it becomes spiritualized (ativahika) and it
glows and flows, like snow melts to water by application of heat.
10 The spiritualized mind, being
awakened, mixes with the holy spirits of departed souls in the other world.
11 When your sense of individual ego is moderated by your practice of meditation, then the perception
of invisible will rise of itself clearly before your mind.
12 When spiritual knowledge gains a firm
footing in your mind, you will perceive more other worlds than you expect.
13 Therefore, O blameless
lady, try your utmost to deaden your desires. When you have gained sufficient strength in that practice,
know yourself to be liberated in this life.
14 When the moon of your intellectual knowledge shines fully with its cooling beams, you shall have
to leave your physical body here in order to see the other worlds.
15 Your fleshy body has no tangible
connection with one that is without flesh, nor can the intellectual body (lingadeha, astral body)
perform any action of the physical system.
16
I have told you all this according to my best knowledge and the state of things as they are. Even
children know that what I say is as effective as the curse or blessing of a god.
17 The habitual reliance of men upon their gross bodies and their fond attachment to them bind their
souls down to the earth. The weakening of earthly desires serves to clothe them with spiritual bodies.
18 Nobody believes that he has a spiritual body, even at his death bed, but everyone thinks a dying
man is dead with his body forever.
19 This body however, neither dies nor is it alive at anytime. Both
life and death, in all respects, are mere appearances of aerial dreams and desires.
20 The life and
death of beings here below are as false as the appearances and disappearance of people in
imagination, or dolls in play or puppet shows.
21 Leela said, “O goddess, the pure knowledge that you have given me has fallen on my ears acts likea healing balm to the pain caused by phenomena.
22 Now tell me the name and nature of the practice
for spiritualization. How it is to be perfected and what is the end of such perfection?”
23 The goddess replied:—
Whatever a man attempts to do here at anytime, he can hardly ever complete it without painful
practice to the utmost of his power.
24 The wise say that practice consists in the association of one
thing with another, in understanding it thoroughly, and in devoting oneself solely to his object.
25 Great souls become successful in this world who are disgusted with the world and are moderate in
their enjoyments and desires. They do not think about seeking what they lack.
26 Those great minds are
said to be best trained who are graced with liberal views, are delighted with the relish of unconcern
with the world, and are enraptured with streams of heavenly joy.
27 Again, they are called the best
practiced in divine knowledge who, by the light of reasoning and scripture, are employed preaching
the absolute non-existence of any distinction between the knower and what is known in this world.
28 What some call practical knowledge is knowing that nothing was produced in the beginning and
nothing that is visible, such as this world or one’s self, is true at anytime.
29 The effect of practicing meditation is a strong tendency of the soul towards the spirit of God, which
results from an understanding of the non-existence of the visible world and the subsidence of
passions.
3 0 But mere knowledge of the nonexistence of the world, without subduing passions, is
known as knowledge without practice, and is of no value to its possessor.
31 Consciousness of the
non-existence of the visible world is the true knowledge of the knowable. The practice of meditation
makes this knowledge a habit in the mind and leads one to his final extinction (nirvana) .
3 2 The
practice of meditation prepares the mind and awakens the intelligence which lay dormant in the dark
night of this world. Consciousness then sheds its cooling showers of reason, like dew drops in the
frosty night of autumn.
Valmiki speaking:—
3 3 As the sage was lecturing in this manner, the day departed for its evening service and led the
assembled train to their evening prayers. After the rising beams of the sun dispelled the darkness of
night, they met again with mutual greetings. >
Chapter 23 — Saraswati & Leela Meditate & Begin Astral Travel
1 Vasishta said:—
After this conversation between Goddess Saraswati and the excellent Leela on that night, the two of
them found Leela’s family and attendants fast asleep in the inner apartment.
2 Saraswati and Leela
entered the shrine that was closely shut on all sides by latches fastened to the doors and windows, and
which was perfumed with the fragrance of heaps of flowers.
3 They sat beside the corpse decorated
with fresh flowers and garments. Their faces shone like the fair full moon and brightened the place.
4 They stood motionless on the spot, as if they were sculptures engraved on marble columns, or
pictures drawn upon the wall.
5 They shook off all their thoughts and cares, and became as withdrawn as the faded blossoms of the
lotus at the end of the day when their fragrance has fled.
6 They remained still, calm and quiet and
without any motion of their limbs, like a sheet of clouds hanging on the mountain top in the calm of
autumn.
7 They continued in fixed attention without any external sensation, like some lonely vines
shriveled for lack of moisture (in samadhi meditation).
8 They were fully impressed with the disbelief
of their own existence, and that of all other things in the world. They were completely absorbed in the
thought of an absolute privation of everything at large.
9 They lost memory of the phantom of the
phenomenal world, which is as unreal as the horn of a hare.
10 What had no existence in the beginning
is still non-existent at present, and what appears existent is as non-existent as water in a mirage.
11 The two ladies became as quiet as inert nature herself, and as still as the sky before the stars rolled
about in its ample sphere.
12 Then they began to move with their own bodies, the goddess of wisdom in her form of intelligence
and the queen in her intellectual and meditative mood.
13 With their new bodies they rose as high as
the width of a hand above the ground, then taking the forms of empty consciousness, they began to rise
in the sky.
1 4 Then the two ladies, their playful open eyes and by their nature of intellectual
knowledge, ascended to the higher region of the sky.
15 They flew higher and higher by force of their intellect and arrived at a region stretching millions of
miles in length.
16 The pair in their ethereal forms looked around according to their nature in search of
some visible objects, but finding no other figure except their own, they became much more attached to
each other by their mutual affection. >
Chapter 24 — Description of the Astral Journey
1 Vasishta continued:—
Thus ascending higher and higher, and by degrees reaching the highest station, they continued viewing
the heavens with their hands clasped together.
2 They saw a vast expanse like a wide extended universal ocean, deep and translucent within, but soft
with ethereal mildness. A cooling breeze infused heavenly delight.
3 They dived into the vast ocean of
emptiness, all delightful and pleasant. It gave them a delight far greater in its purity than what is
derived from the company of the virtuous.
4 They wandered about all sides of heaven under the beams
of the full moon shining above them. They lingered under the clear vault of clouds covering the
mountain tops of Meru, as if under the dome of a huge white washed building.
5 They roved by the regions of spiritual masters (siddhas, adepts) and male nature spirits
(gandharvas). They breathed the charming fragrance of mandara garlands and, passing the lunar
sphere, they inhaled the sweet scent exhaled by the breeze from that nectar-like lunar orb.
6 Tired and perspiring profusely, they bathed in the lakes of showering clouds filled with the blushing
lotuses of lurid lightning flashing within them.
7 They freely strolled at random on all sides, and
alighted on the tops of high mountains like fluttering bees, appearing like filaments of the lotus-like
earth below.
8 They also roved under the vaults of some cloud fragments scattered by the winds, and
raining like the cascade of the Ganges River, thinking them as shower bath-houses in the air.
9 Then
failing in their strength, they paused in many places with slow and slackened steps.
They saw emptiness full of great and wonderful works.
10 They saw what they had never seen before,
the tremendous depth of the void that was not filled up by the myriads of worlds which kept revolving
in it.
11 Over and over and higher and higher, they saw the celestial spheres filled with luminous orbs
adorned with their ornamental stars wandering one above and around the other.
12 Huge mountainous
bodies like Mount Meru moved about in empty space and emitted a reddish glare on all sides, like a
flame of fire from within their bowels.
1 3 There were beautiful tablelands, like those of the
Himalayas, with their pearly peaks of snow. There were mountains of gold spreading a golden color
over the land.
14
In one place they saw mountains of emerald tinting the landscape with a lush green
like a field of fresh grass. In other places they saw some dark cloud dimming the sight of the spectator
and hiding the spectacle in dark blackness.
15 They saw also tracts of blue sapphire with vines of
parijata flowers blooming like banners in the blue skies.
16 They saw the minds of spiritual masters (siddhas) in flight faster than the swift winds. They heard
the vocal music of the songs of heavenly nymphs in their aerial abodes.
17 All the great bodies in the
universe (the planetary system) were in continual motion. Spirits of the gods and demigods moved
about unseen by one another.
18 Groups of spiritual beings, the kushmandas, rakshasas and pisachas,
were seated in aerial circles at the borders. Winds and gales blew with full force in their ethereal
course.
19
In some places they heard clouds roaring loudly, like the rumbling wheels of heavenly cars,
and the noise of rapid stars resembled the blowing of pneumatic engines.... >
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and so on continues...
