In article <11**********************@g47g2000cwa.googlegroups .com>,
<ma*********@gmail.com> wrote:
:I need an algorithm/program that can computer planetory position data
:for a given date/time/place. Can anyone please help me to find the same
:(source code/algorithm) or explain me how to find/calculate it.
There is no known accurate way to calculate this. This is the "N-Body
Problem", the mathematics of which is chaotic. The positions of the
planets is affected by the position of all the other planets, and
by the position of Sol, and by the composition of the planets, and
by the stellar dynamics of Sol (which determine the mass distribution) --
and all of these are also affected by the positions and mass of the
thousands of minor planets and the positions and mass of all of the
billions of smaller objects.
For example, the position of some of the "shepard moons" in Saturn's
rings depend upon the mass distribution of the ring particles, which in
turn depends upon the planetary electrical field and the details of how
Io ejects mass into orbit... But then the position of Saturn depends
upon the position of the shepard moons, and that affects everything
else.
If you don't mind approximations, you can model the positions
independantly using simple elipses whose foci are determined by the
relative masses of Sol and the planet in question. That is, however,
really only usable for the high-mass planets; the low- mass planets are
much more affected by the influence of the other objects. Keep in mind,
though, that the existance of Neptune and Pluto were deduced based upon
the wobbles in the orbits of the other planets... Mercury in particular
has really noticable orbital deviations from the simple elipse model,
due to relativistic effects (scientists spend years searching for a
planet hidden within Mercury's orbit, until relativity was successfully
applied.)
Beyond that... search for emphemeris programs, such as
http://www.astro.com/swisseph/?lang=e
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