//return Ecliptic Coordinates with necessary orbital corrections
//T - Time in Julian centuries since J2000
Vector <double> GetMoonCoor(double T)
{
double Arcs = 3600.0 * 180.0 / Math.PI;
double L_0, l, ls, F, D, dL, S, h, N;
// Mean elements of lunar orbit
L_0 = Astro.Frac(0.606433 + 1336.855225 * T); // mean longitude [rev]
l = 2 * Math.PI * Astro.Frac(0.374897 + 1325.552410 * T); // Moon's mean anomaly
ls = 2 * Math.PI * Astro.Frac(0.993133 + 99.997361 * T); // Sun's mean anomaly
D = 2 * Math.PI * Astro.Frac(0.827361 + 1236.853086 * T); // Diff. long. Moon-Sun
F = 2 * Math.PI * Astro.Frac(0.259086 + 1342.227825 * T); // Dist. from ascending node
// Perturbations in longitude and latitude
dL = +22640 * Math.Sin(l) - 4586 * Math.Sin(l - 2 * D) + 2370 * Math.Sin(2 * D) + 769 * Math.Sin(2 * l)
- 668 * Math.Sin(ls) - 412 * Math.Sin(2 * F) - 212 * Math.Sin(2 * l - 2 * D) - 206 * Math.Sin(l + ls - 2 * D)
+ 192 * Math.Sin(l + 2 * D) - 165 * Math.Sin(ls - 2 * D) - 125 * Math.Sin(D) - 110 * Math.Sin(l + ls)
+ 148 * Math.Sin(l - ls) - 55 * Math.Sin(2 * F - 2 * D);
S = F + (dL + 412 * Math.Sin(2 * F) + 541 * Math.Sin(ls)) / Arcs;
h = F - 2 * D;
N = -526 * Math.Sin(h) + 44 * Math.Sin(l + h) - 31 * Math.Sin(-l + h) - 23 * Math.Sin(ls + h)
+ 11 * Math.Sin(-ls + h) - 25 * Math.Sin(-2 * l + F) + 21 * Math.Sin(-l + F);
// Ecliptic longitude and latitude
Vector <double> v = new Vector <double>();
v.X = 2 * Math.PI * Astro.Frac(L_0 + dL / 1296.0e3); // [rad]
v.Y = (18520.0 * Math.Sin(S) + N) / Arcs; // [rad]
return(v);
}
//return Ecliptic Coordinates with necessary orbital corrections
//T - Time in Julian centuries since J2000
Vector <double> GetSunCoor(double T)
{
// Mean anomaly and ecliptic longitude
double M = 2 * Math.PI * Astro.Frac(0.993133 + 99.997361 * T);
double L = 2 * Math.PI * Astro.Frac(0.7859453 + M / (Math.PI * 2) +
(6893.0 * Math.Sin(M) + 72.0 * Math.Sin(2.0 * M) + 6191.2 * T) / 1296.0e3);
return(new Vector <double> {
X = L, Y = 0
});
}
int GetMoonDay(DateTime date)
{
double eq, eq1, eq2;
int monthH = date.Month;
int yearH = date.Year;
if (date.Month <= 2)
{
monthH += 12;
yearH--;
}
eq = Math.Floor(yearH / 100.0);
eq1 = Math.Floor(eq / 3) + Math.Floor(eq / 4) + 6 - eq;
eq2 = (Math.Round(Astro.Frac(yearH / eq) * 209) + monthH + eq1 + date.Day) / 30;
return((int)(Astro.Frac(eq2) * 30 + 1));
}
