True and Mean / Parallax

[Guest guest]

Dear Sateesh,

 

> Re. the below Paragraph, what is the difference between " True " and " Mean "

> Nodes - which should we be using for the most accurate positions of Rahu &

> Ketu?

 

The so-called " true " nodes are the intersection points of the momentary apparent

lunar orbit and the ecliptic (or, to be more correct, the momentary apparent

orbit of Sun).

 

Actually the expression " true nodes " is a misnomer. It is rather " hypothetical

nodes " . The true nodes are true only twice a month, when Moon crosses the

ecliptic. At other times, the positions given for them are just a hypothesis.

 

Mean nodes always move backwards (which is what Rahu and Ketu are supposed to

do, as per scriptures and classics). True nodes have an osculating motion - they

move forward for sometime and backward for sometime (but backward overall).

 

Based on my researches with divisional charts and Narayana dasa, I strongly

recommend the so-called " mean " nodes. Of course, others may differ.

 

> Also, the same question for " Parallax Off " or " Parallax On " for the Moon's

> Position - what's the difference, and which do Learned List Members feel

> should be used out of the two types? Seeing as it significantly alters the

> Dates of Dasas by " Switching " between Parallax On or Off.

 

On the matter of whether we should use the geocentric positions or topocentric

position (w.r.t. the place of birth/event), whether we should use the position

where the planet really is or the position where we see the planet (this is

different from the true position because of parallax and light's finite speed)

are issues that we have to grope and cope with.

 

> Many thanks.

>

> Very best regards - Sateesh.

> -

> <RGDREYER

>

> > It is the same with the debate about true v. mean nodes. While Parasara

> > indeed used mean nodes, this can also be attributed to the fact that true

> > nodes were not calculated then. If we develop the means to calculate more

> > sophisticated astronomical data, should we not use it because it was not

> > mentioned in Parasara?

 

(1) Some people think as you suggested above and consider new parameters that we

know Parasara did not. They look at Parasara as a scientist who found truth thru

statistical research.

 

(2) Some people (like me) think that the basis of Parasara's knowledge wasn't

statistical research and reductionist logic. We believe that it was " revealed "

knowledge. If something is compatible with Parasara's teachings, we research it

even though it wasn't explicitly mentioned by Parasara, because there is a

chance that Parasara mentioned it in some lost chapters. We also do research,

but within the parameters set by Parasara.

 

May Jupiter's light shine on us,

Narasimha