//public static Vector4 GetAbsolutePositionForParabolicOrbit_AU()
//{ }
//public static Vector4 GetAbsolutePositionForHyperbolicOrbit_AU(OrbitDB orbitDB, DateTime time)
//{
//}
public static double GetTrueAnomaly(OrbitDB orbit, DateTime time)
{
TimeSpan timeSinceEpoch = time - orbit.Epoch;
// Don't attempt to calculate large timeframes.
while (timeSinceEpoch > orbit.OrbitalPeriod && orbit.OrbitalPeriod.Ticks != 0)
{
long years = timeSinceEpoch.Ticks / orbit.OrbitalPeriod.Ticks;
timeSinceEpoch -= TimeSpan.FromTicks(years * orbit.OrbitalPeriod.Ticks);
orbit.Epoch += TimeSpan.FromTicks(years * orbit.OrbitalPeriod.Ticks);
}
double m0 = Angle.ToRadians(orbit.MeanAnomalyAtEpoch);
double n = Angle.ToRadians(orbit.MeanMotion);
double currentMeanAnomaly = OrbitMath.GetMeanAnomalyFromTime(m0, n, timeSinceEpoch.TotalSeconds);
double eccentricAnomaly = GetEccentricAnomaly(orbit, currentMeanAnomaly);
return(OrbitMath.TrueAnomalyFromEccentricAnomaly(orbit.Eccentricity, eccentricAnomaly));
/*
* var x = Math.Cos(eccentricAnomaly) - orbit.Eccentricity;
* var y = Math.Sqrt(1 - orbit.Eccentricity * orbit.Eccentricity) * Math.Sin(eccentricAnomaly);
* return Math.Atan2(y, x);
*/
}