What is the efficient way to calculate the state vector of planets and moons?
The coordinate system for planets would be with center in Solar System Baricenter, for Moon- with center in Earth and in Solar System Baricenter.
The use of JPL kernels (
de430.bsp) and python
jplephem package worked for me.
Compared with the JPL Horizons, results are the same.
from jplephem.spk import SPK kernel = SPK.open('de430.bsp') position = kernel[0,3].compute(2457061.666666667) print(position)