/// <inheritdoc/>
public override Equator GetEquatorCoordinate(DateTime time, bool isApparent = false)
{
double T = (Julian.ToJulianDay(time) - 2451545.0) / 36525.0;
double L0 = 280.46645 + 36000.76983 * T + 0.0003030 * T * T;
double M = 357.52910 + 35999.05030 * T - 0.0001559 * T * T - 0.00000048 * T * T * T;
double e = 0.016708617 - 0.000042037 * T - 0.0000001236 * T * T;
L0 = BasicTools.SimplifyAngle(L0);
M = BasicTools.SimplifyAngle(M);
e = BasicTools.SimplifyAngle(e);
double C = Math.Abs((1.914600 - 0.004817 * T - 0.000014 * T * T)) * Math.Sin(M * (Math.PI / 180.0)) + (0.019993 - 0.000101 * T) * Math.Sin(2 * M * (Math.PI / 180.0)) + 0.000290 * Math.Sin(3 * M * (Math.PI / 180.0));
C = BasicTools.SimplifyAngle(C);
double theta = L0 + C;
double theta2000 = theta - 0.01397 * (time.Year - 2000);
double omega = 125.04 - 1934.136 * T;
omega = BasicTools.SimplifyAngle(omega);
double lambda = theta - 0.00569 - 0.00478 * Math.Sin(omega * (Math.PI / 180.0));
double sinDelta, delta, alpha;
if (isApparent)
{
sinDelta = Math.Sin((CoordinateSystem.GetEclipticObliquity(time, false) + 0.00256 * Math.Cos(omega) * (Math.PI / 180.0)) * (Math.PI / 180.0)) * Math.Sin(lambda * (Math.PI / 180.0));
delta = Math.Asin(sinDelta) * (180.0 / Math.PI);
alpha = Math.Atan2(Math.Cos((CoordinateSystem.GetEclipticObliquity(time, false) + 0.00256 * Math.Cos(omega) * (Math.PI / 180.0)) * (Math.PI / 180.0)) * Math.Sin(lambda * (Math.PI / 180.0)), Math.Cos(lambda * (Math.PI / 180.0))) * (180.0 / Math.PI);
}
else
{
sinDelta = Math.Sin(CoordinateSystem.GetEclipticObliquity(time, false) * (Math.PI / 180.0)) * Math.Sin(theta2000 * (Math.PI / 180.0));
delta = Math.Asin(sinDelta) * (180.0 / Math.PI);
alpha = Math.Atan2(Math.Cos(CoordinateSystem.GetEclipticObliquity(time, false) * (Math.PI / 180.0)) * Math.Sin(theta2000 * (Math.PI / 180.0)), Math.Cos(theta2000 * (Math.PI / 180.0))) * (180.0 / Math.PI);
}
if (alpha <= 0)
{
while (!(alpha >= 0 && alpha <= 360))
{
alpha += 360;
}
}
Equator c = new Equator
{
RA = alpha,
Dec = delta
};
return(c);
}
/// <inheritdoc/>
public override double GetToEarthDistance(DateTime time)
{
double T = (Julian.ToJulianDay(time) - 2451545.0) / 36525.0;
double M = 357.52910 + 35999.05030 * T - 0.0001559 * T * T - 0.00000048 * T * T * T;
double e = 0.016708617 - 0.000042037 * T - 0.0000001236 * T * T;
M = BasicTools.SimplifyAngle(M);
e = BasicTools.SimplifyAngle(e);
double C = Math.Abs((1.914600 - 0.004817 * T - 0.000014 * T * T)) * Math.Sin(M * (Math.PI / 180.0)) + (0.019993 - 0.000101 * T) * Math.Sin(2 * M * (Math.PI / 180.0)) + 0.000290 * Math.Sin(3 * M * (Math.PI / 180.0));
C = BasicTools.SimplifyAngle(C);
double v = M + C;
v = BasicTools.SimplifyAngle(v);
double distance = 1.0000011018 * (1 - e * e) / (1 + e * Math.Cos(v * (Math.PI / 180.0)));
return(distance);
}