Fast and stable solver for Kepler's equation extracted from exoplanet.
The best way to install is using pip:
python -m pip install kepler.py
This package exposes two functions:
kepler
: Solves Kepler's equation and returns the cosine and sine of the true anomaly:
import kepler
eccentric_anomaly, cos_true_anomaly, sin_true_anomaly = kepler.kepler(mean_anomaly, eccentricity)
solve
: A lower-level interface that is used bykepler
to actually do the solving (Note that this will return garbage for eccentricities out of the range zero to one):
import kepler
eccentric_anomaly = kepler.solve(mean_anomaly, eccentricity)