planetarium software based on gravity

On 30 Oct 2004 18:07:07 GMT, Laurens Rossi
wrote:

What I'm interested in, is the motion of the sun itself related to the
position and motion of the planets.

The sun moves about the center of gravity of the solar system, the
barycenter, which is roughly 1/1000th of way between the Sun and
Jupiter. Steve Moshier is kind enough to provide a program that
computes positions using numerical integration (that is, using
gravity): http://www.moshier.net/ssystem.html.

Hi All!

I have been searching the web for software which calculates the absolute
position of planets and the sun, which is based on the laws of gravity. All
software I found is based on the trigonometrical calculations with the
current postion and speed of the planets. These programs seem to keep the
sun as an absolute reference point and to calculate the planets' orbits.

What I'm interested in, is the motion of the sun itself related to the
position and motion of the planets.

Has anyone seen such software?

It would be great if:
* the output can be a text table with positions of sun and planets
* the software is in perl, c++, java or some other source code so I can
adjust it
* the software is stable over a longer calculation range (so planets do not
shoot out of orbit after a few hunderd years...

Performance is not important...

Or is the output that I need available on the net somewhere?

All information will be appreciated!

Laurens
(just remove the *** to mail me)

Laurens Rossi wrote:
Hi All!

I have been searching the web for software which calculates the absolute
position of planets and the sun, which is based on the laws of gravity. All
software I found is based on the trigonometrical calculations with the
current postion and speed of the planets. These programs seem to keep the
sun as an absolute reference point and to calculate the planets' orbits.

What I'm interested in, is the motion of the sun itself related to the
position and motion of the planets.


Hi Laurens,

I'm not sure it'll do exactly what you're looking for, but libnova can
be used to make this kind of calculations.

http://libnova.sourceforge.net/

Otherwise, there are more open source libraries in the Science &
Engineering Astronomy section at http://freshmeat.net which may
contain the code you're looking for.

Best of luck,

Steve

--
Steve Maddison
Den Haag, The Netherlands
http://www.cosam.org/