Re: Astronomical coordinates

Jonathan Silverlight wrote:
>
> In message <43C65467.9848F799@xxxxxxxxxxxxxxxxx>, Jake
> <jakmal@xxxxxxxxxxxxxxxxx> writes
> >Five replies to this thread and not one of them addressing the original
> >subject matter.
> >
> >How sadly illustrative of what sci.astro has become.
>
> In my case, it's because I was fairly sure Jim Green's reply had
> absolutely nothing to do with the question, even though I was much less
> sure what the questioner wanted ;-) It would be helpful to know why the
> question is being asked.

Because I wanted to convert from celestial coordinates (aka equatorial
coordinates) to heliographic coordinates, which AFAIK are always
heliographic _ecliptic_ coordinates. I don't see the point of
heliographic equatorial coordinates, although such an oddity may exist
so maybe I should have been more specific.

> This page has what looks like a useful description of doing the reverse
> (converting heliocentric co-ordinates to right ascension/declination)
> <http://home.att.net/~srschmitt/script_planet_orbits.html>
> Here's another by Paul Schlyter
> <http://www.njsas.org/projects/tidal_forces/altaz/pausch/tutorial.html>
> I'm probably wrong, but it seems to me that converting from celestial
> co-ordinates to heliocentric is about determining the orbit of an
> object, which is a much bigger project.

Thanks, Jonathan.
.