Re: [guide-user] Of many things...

Laurent Zimmermann Aug 17, 2000

> > Second, I might attempt to write code that computes positions for
> > these objects by interpolating the ephemerides. I dislike this idea
> > (compared to just using elements, it's a horrible kludge), but it may
> > be the only option.
>
> This isn't the ONLY option. Another option would be to use e.g.
> Gauss' method to compute the orbial elements from three ephemeris
> positions. If you want to be fancy, you could, after having obtained
> preliminary orbital elements from Gauss' method, even refine these
> elements from a least-square analysis using all ephemeris positions.
> In this way the orbital elements used to compute the ephemeris ought
> to be recreated.


I believe that in this case the roundigns of the ephemeris coordinates might be a problem. A better way could be the Lagrange's method that makes use of the coordinates and their first and second time derivatives, which might be better determined from a fitting on the ephemeris.


Laurent Zimmermann *<|:-)
http://users.skynet.be/zmn/cab/cab.html