The classics do not specifically mention true or mean. In fact, these two adjectives are modern inventions.
But, classics do mention that Rahu and Ketu are always retrograde. That seems to suggest mean nodes. But whether that was done for convenience or reason is arguable.
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> Please tell me what is arbitrary about the computation of the nodes'
> positions. Or tell me what is hypothetical about it. If you believe
> that since they are computed they are hypothetical, then all planetary
> positions are computed and thus are hypothetical.
Well, there is a big difference between nodes and planets. When I say Sun or Moon or Mars, I see them physically. There is nothing called Rahu or Ketu physically. So I can define them in different ways. It is just a matter of how you define it. That is why I call it arbitrary.
If you like true nodes, you probably define nodes as the intersection between the momentary orbits. But why should I define that way only? There is nothing called a momentary orbit. At a moment, there is only a position. The so-called momentary orbit is just a hypothetical construct.
When different definitions can be employed and there is no compelling reason to use either definition, I call it arbitrary.
for a different way of articulating what I just said.
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I have a lot of experience not only with divisional chart analysis but also with Narayana dasa evaluated for each divisional charts. Unlike chara dasa, Narayana dasa can be computed separately for each divisional chart (use JHora for it). If Rahu and Ketu change signs in a division, Narayana dasa will change, sometimes drastically.
Based on my studies in the timing of events using Narayana dasa of divisional charts, I am fully convinced that mean nodes are the way to go. That would be my advice to anyone interested in it.
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I have long had one thought regarding planetary longitudes too. Planets are not points. They are objects occupying a range of longitudes in the zodiac. Look at Sun and Moon for example. They look so big. Still, we abstract them as points in astrology. The question is, which point should be taken as their center?
Normally, we take the centerof gravity of planets and take its co-ordinates. The co-ordinates of the center of gravity of Moon are taken as the co-ordinates of Moon.
Implicit in this is the assumption that planets exert influence on us thru gravity. But, is that true? How do planets influence our fortunes? Is it thru gravity or light or electromagnetism or something else that we don't understand?
If it is thru some other medium not yet understood that planets influence our lives, say some kind of spiritual energy? If so, can the "spiritual center" of Moon be slightly off the center of gravity of Moon?
In other words, however accurate we make our calculations, there is an uncertainty at the end. It is not impossible that some kind of minor correction should be applied to planetary longitudes and latitudes at the end.
Unless we understand the answers to these questions well, we cannot authentically answer if true nodes or mean nodes should be used.
I am really pressed for time and may not be able to engage on this topic. Please give serious consideration to various points I made.
May Jupiter's light shine on us,