/// <summary>
/// Creates a new instance of the class given ECI coordinates.
/// </summary>
/// <param name="eci">The ECI coordinates.</param>
/// <param name="date">The Julian date.</param>
public Geo(Eci eci, Julian date)
: this(eci.Position,
(Globals.AcTan(eci.Position.Y, eci.Position.X) - date.ToGmst()) % Globals.TwoPi)
{
}
