Just what I know, let me color what is fairly widespread generally recognized in black, what seems to me relatively straightforward extrapolation in blue and what is more speculative or associative or at least not generally mentioned in red, but the boundaries are somewhat floating...
Astronomically, the lunar nodes are at the intersections between the orbits of the earth around the sun (or from the perspective of the earth of the apparent orbit of the sun around the earth) and the orbit of the moon around the earth, to the degree that there is an orbital plane for the moon at all - hence mean nodes and true nodes which are closer to reality.
In the immediate sense they are needed to calculate eclipses. Whenever sun and moon are both near the nodes, they are also close in the sky, the moon is close to the orbit of the sun, and vice-versa.
Then at new moon the moon may pass between earth and sun, obscuring the sun partially or totally, which is something that happens typically twice every year, one with the south node, once with the north node, but is only visible at certain regions on the earth, i.e. without prior knowledge something most people might never witness in their lives.
And at full moon, the earth may be in the path between sun and moon, obscuring the moon partially or totally, with also happens typically twice every year, one with the south node, once with the north node, but is then usually visible in very large area, i.e. if you live in a place where there is often a clear sky and you do look up in the sky at night at full moon, then you are likely to spot several lunar eclipses in your life time.
This means that in ancient times people maybe first noticed lunar eclipses, and presumably not knowing much about celestial mechanics assumed some creature would temporarily swallow the moon and then spit it out again.
With more experience, observing also solar eclipses, people probably noticed that lunar and solar eclipses usually occurred close to each other, the full moon before or after a new moon, with the sun being "swallowed" at one side of the sky, the one with the sun and then also the moon at new moon, and the other one at full moon on the opposite side.
This probably lead to assuming that the swallowing was due to a creature that has maybe two heads or something like that, like a snake/dragon* with head and tail. Also via swallowing and given that the intestinal tract is something like a "snake" in the body, the other end might be the anus of the creature.
* Remember that drakon in Greek was typically rather a snake, a creature without legs, I posted links around that recently, don't remember in which thread, but just look it up in Wikipedia...
I am not sure how the relation of the nodes in astrology with reincarnation came about. In a way you are eating you way through time, you grow by eating, get energy from it, but at the same time "each bite" also brings you closer to the end...
Maybe something like this, and maybe going back to an "Age of Taurus": In vedic astrology apparently the second house is related to the mouth and speech, which partially similar to the view in the West, where the throat and neck are 2/Taurus, but not speech (learned that about speech from wanda here recently). At least in the West, the anus or at least the last part of the intestines would be attributed to Scorpio,
but not the buttocks, there there seem to be two different attributions in the West going back 2000 years, to Sagittarius as prolongation of the thighs and to Libra because of symmetric perfectly round orbs and in height near the symmetric kidneys, but that is an other topic.
So, maybe Taurus-Scorpio, which makes me think of holy cows in India and of the following:
A cow eats grass and produces dung, but the dung is then a good fertilizer, hence there is a cycle, what is dirty stuff out an anus for most animals is good food for many plants. Maybe in that line an idea of reincarnation emerged, the matter is recycled.
In India n.node and s.node are planets 8 and 9,
which might relate them to planet 8 and 9 in the West, namely Uranus (ur-anus) and Neptune. Also, there is some ambivalence between the nodes, since seen from the southern hemisphere the rising node is not the n.node but the s.node, so which is which is somewhat of a matter of the point of view. Similarly, Neptune was sighted by Galileo when observing the moons of Jupiter, he noted the dot in his journal, but did not realize he had seen a planet, considered it a fixed star apparently, so not so clear which planet was discovered first.
There is also the theme of consciousness and unconsciousness, with the moon above the ecliptic being more consciousness and hence the n.node rather being where one goes consciously and the s.node where things sink back into unconsciousness.
In India, both nodes are considered rather "bad", both as animals that eat stuff and do not have lots of consciousness, while in the West, the n.node is often considered the way to go, also where the tendency naturally goes in life, with a shift from s.node to n.node themes as one grows older, and I think I can see that in my life.
But... in the analogy of the intestinal "snake", you cannot just eat, it also has to come out again, so a certain balance is still needed. Also, it is true that people usually do not have full control over mouth and anus, else there would be no fat people, for example. Which may well be why both nodes are considered "bad" in India.
But there are also some more metaphysical aspects to the node.
They are in a way a Möbius strip, something that is both one and two at the same time, like also the yin-yang symbol. If you look at the nodes as one animal, it is both itself and itself, a catdog
Also, topologically (in the mathematical sense), a human body if you neglect the nose would be a torus, i.e. a donut/bagel, with the intestinal tract rather a hole in the body, not really inside, only what permeates the skin/membranes in mouth/stomach/intestines.
Liz Greene about the nodes
in an article about the company birth chart of Astrodienst:
These mysterious points are often associated with "fate" because they represent the intersection points of the Sun's and Moon's orbits: a combination of "destiny" (the Sun) and "embodiment" (the Moon).
A lot is maybe still a mystery...
What I see them is as gates, with somewhat of an instinctive side, too, and triggered when planets pass there, so that some things that had been building up would be realized, in different ways, sometimes gently, sometimes violently, and, again, only partially under control... In the past I had seen the s.node in death charts, but more recently noticed that also the n.node seems to occur there or near there, as from a certain age any step forward is close to the end, but with maybe the option of rebirth...
Maybe not the most carefully written post, but maybe there is something in it for some, maybe a new helpful element in the interpretation...
