I am working on an orbital dynamics code and, for fun, I would like to model the Sun-Earth-Moon system with my code. I can look up the masses of each object just fine, as well as average distances and relative velocities (which I can also calculate). However, I would like to model the Sun-Earth-Moon system in great detail. I would like to know the positions and velocities of each object on any given day (today works just fine) so that I can represent the orbits of these objects with great accuracy, hopefully even reproducing their actual ellipticity. Where can I find values for:
- current Sun-Earth distance
- current Earth-Moon distance
- current Sun-Moon angular separation
- current velocity of Earth relative to Sun (or relative to Sun-Earth(-Moon?) center of mass)
- current velocity of Moon relative to Earth
and, maybe even
- current velocity of Sun relative to Sun-Earth(-Moon?) center of mass.
Is there any resource that provides these current values?