public static Coordinates.Spherical From(Coordinates.Cartesian3D point)
{
var r = Sqrt(Pow(point.X, 2) + Pow(point.Y, 2) + Pow(point.Z, 2));
var phi = AngleMath.Atan2(point.Y, point.X);
var theta = AngleMath.Atan2(Sqrt(Pow(point.X, 2) + Pow(point.Y, 2)), point.Z);
return(new Coordinates.Spherical(
phi: phi,
theta: theta,
r: r));
}