Minor Planets documentation update suggestion

[xmichaelx]

Documentation for Minor Planets section of Kepler Orbits should mention that used propagator does not take into orbit perturbations from larger bodies and should not be used for propagating raw mpcorb.dat orbits without previous integration closer to desired epoch.

Such integration can be performed using INTEGRAT tool here https://www.projectpluto.com/pluto/integrat.htm - this takes into account perturbations from large planets along with Ceres, Pallas and Vesta and leads to precise results.

For 2000 PQ9 and 40 days old orbit this was a difference between 135 and 0.1 arcsec correlation.

It would help to have a paragraph or two explaining that for precision one need to propagate orbits within mpcorb.dat file to the day of the observation. Preferably using propagator which takes into account perturbations stemming from planets and larger bodies such as Ceres, Vesta and Pallas. Example of such propagator available for free is INTEGRAT and can be compiled from sources in following repos: https://github.com/Bill-Gray/lunar and https://github.com/Bill-Gray/jpl_eph