protected override void OnTimeChanged()
{
// Calculate geocentric coordinates
Vector3 bodyLocation = this.HeliocentricLocation - Earth.Instance.HeliocentricLocation;
EclipticCoordinate geocentricCoordinate = new EclipticCoordinate(bodyLocation);
this.EquatorialCoordinate = ODE.Astronomy.EquatorialCoordinate.From(geocentricCoordinate, this.Time);
base.OnTimeChanged();
}
// Time not used in current calculation, but might be need in future refinements
public static EquatorialCoordinate From(EclipticCoordinate eclipticCoordinate, Time time)
{
// Calculate right ascension and declination
Angle angleEpsilon = Angle.FromDegrees(23.4392911); // obliquity of the ecliptic -- see Meeus, pg. 92
Angle angleRightAscension = Angle.ArcTangent(eclipticCoordinate.Longitude.Sine * angleEpsilon.Cosine - eclipticCoordinate.Latitude.Tangent * angleEpsilon.Sine, eclipticCoordinate.Longitude.Cosine);
angleRightAscension.NormalizePositive();
Angle angleDeclination = Angle.Zero;
angleDeclination.Sine = eclipticCoordinate.Latitude.Sine * angleEpsilon.Cosine + eclipticCoordinate.Latitude.Cosine * angleEpsilon.Sine * eclipticCoordinate.Longitude.Sine;
angleDeclination.NormalizeAroundZero();
return(new EquatorialCoordinate(angleRightAscension, angleDeclination));
}
