Data are given in Cartesian coordinates in units of 0.01 AU (e.g., 100=1.00 AU), and restricted to +/-99.99 AU along all three axes. The (X,Y) Plane is the plane of the Ecliptic, with the X-axis oriented along the line of the Equinoxes (+=Vernal, -=Autumnal), and the Y-axis oriented along the line of the Solstices (+=Summer, -=Winter). The Z-axis is oriented with respect to the ecliptic pole (+=NEP, -=SEP).
Files are column-oriented ASCII text, suitable for input for plotting using, for example, Mongo and its variants, or most PC/Mac-based plotting programs.
Data in each file are organized as follows:
x1 y1 z1
x2 y2 z2
.. .. ..
xN yN zN
The number of points on each orbit is 201 (200 points, plus a the first
point repeated to make sure the orbit close), which was chosen to give a
relatively smooth plot on most devices. If you need more precision, simple
interpolation should do the trick. For the comets, some are sufficiently
elliptical that they have been truncated for Cartesian coordinates (along
any axis) beyond 100 AU, and contain fewer than 200 points.
Each file is about 4Kb in size.Data were generated using a simple calculation based on the orbital elements of the planets adapted from a solar system grapher (solsys) written by Steve Allen at the Lick Observatory.
Updated: 1997 December 29 [rwp]