//Static methods
/////////////////////////////// Implementation ////////////////////////////////
public static double MeanGreenwichSiderealTime(double JD)
{
//Get the Julian day for the same day at midnight
DT date = new DT();
date.SetJD(JD, DT.AfterPapalReformJD(JD));
double[] D = date.Get();
int Year = (int)D[0];
int Month = (int)D[1];
int Day = (int)D[2];
int Hour = (int)D[3];
int Minute = (int)D[4];
double Second = D[5];
date.Set(Year, Month, Day, 0, 0, 0, date.InGregorianCalendar());
double JDMidnight = date.Julian();
//Calculate the sidereal time at midnight
double T = (JDMidnight - 2451545) / 36525;
double TSquared = T * T;
double TCubed = TSquared * T;
double Value = 100.46061837 + (36000.770053608 * T) + (0.000387933 * TSquared) - (TCubed / 38710000);
//Adjust by the time of day
Value += (((Hour * 15) + (Minute * 0.25) + (Second * 0.0041666666666666666666666666666667)) * 1.00273790935);
Value = CT.D2H(Value);
return(CT.M24(Value));
}
public static COR Equatorial2Topocentric(double Alpha, double Delta, double Distance, double Longitude, double Latitude, double Height, double JD)
{
double RhoSinThetaPrime = CAAGlobe.RhoSinThetaPrime(Latitude, Height);
double RhoCosThetaPrime = CAAGlobe.RhoCosThetaPrime(Latitude, Height);
//Calculate the Sidereal time
double theta = CAASidereal.ApparentGreenwichSiderealTime(JD);
//Convert to radians
Delta = CT.D2R(Delta);
double cosDelta = Math.Cos(Delta);
//Calculate the Parallax
double pi = Math.Asin(GFX.g_AAParallax_C1 / Distance);
double sinpi = Math.Sin(pi);
//Calculate the hour angle
double H = CT.H2R(theta - Longitude / 15 - Alpha);
double cosH = Math.Cos(H);
double sinH = Math.Sin(H);
//Calculate the adjustment in right ascension
double DeltaAlpha = Math.Atan2(-RhoCosThetaPrime * sinpi * sinH, cosDelta - RhoCosThetaPrime * sinpi * cosH);
COR Topocentric = new COR();
Topocentric.X = CT.M24(Alpha + CT.R2H(DeltaAlpha));
Topocentric.Y = CT.R2D(Math.Atan2((Math.Sin(Delta) - RhoSinThetaPrime * sinpi) * Math.Cos(DeltaAlpha), cosDelta - RhoCosThetaPrime * sinpi * cosH));
return(Topocentric);
}
public static double ApparentGreenwichSiderealTime(double JD)
{
double MeanObliquity = CAANutation.MeanObliquityOfEcliptic(JD);
double TrueObliquity = MeanObliquity + CAANutation.NutationInObliquity(JD) / 3600;
double NutationInLongitude = CAANutation.NutationInLongitude(JD);
double Value = MeanGreenwichSiderealTime(JD) + (NutationInLongitude * Math.Cos(CT.D2R(TrueObliquity)) / 54000);
return(CT.M24(Value));
}
public static CAAParabolicObjectDetails Calculate(double JD, CAAParabolicObjectElements elements)
{
double Epsilon = CAANutation.MeanObliquityOfEcliptic(elements.JDEquinox);
double JD0 = JD;
//What will be the return value
CAAParabolicObjectDetails details = new CAAParabolicObjectDetails();
Epsilon = CT.D2R(Epsilon);
double omega = CT.D2R(elements.omega);
double w = CT.D2R(elements.w);
double i = CT.D2R(elements.i);
double sinEpsilon = Math.Sin(Epsilon);
double cosEpsilon = Math.Cos(Epsilon);
double sinOmega = Math.Sin(omega);
double cosOmega = Math.Cos(omega);
double cosi = Math.Cos(i);
double sini = Math.Sin(i);
double F = cosOmega;
double G = sinOmega * cosEpsilon;
double H = sinOmega * sinEpsilon;
double P = -sinOmega * cosi;
double Q = cosOmega * cosi * cosEpsilon - sini * sinEpsilon;
double R = cosOmega * cosi * sinEpsilon + sini * cosEpsilon;
double a = Math.Sqrt(F * F + P * P);
double b = Math.Sqrt(G * G + Q * Q);
double c = Math.Sqrt(H * H + R * R);
double A = Math.Atan2(F, P);
double B = Math.Atan2(G, Q);
double C = Math.Atan2(H, R);
C3D SunCoord = CAASun.EquatorialRectangularCoordinatesAnyEquinox(JD, elements.JDEquinox);
for (int j = 0; j < 2; j++)
{
double W = 0.03649116245 / (elements.q * Math.Sqrt(elements.q)) * (JD0 - elements.T);
double s = CalculateBarkers(W);
double v = 2 * Math.Atan(s);
double r = elements.q * (1 + s * s);
double x = r * a * Math.Sin(A + w + v);
double y = r * b * Math.Sin(B + w + v);
double z = r * c * Math.Sin(C + w + v);
if (j == 0)
{
details.HeliocentricRectangularEquatorial.X = x;
details.HeliocentricRectangularEquatorial.Y = y;
details.HeliocentricRectangularEquatorial.Z = z;
//Calculate the heliocentric ecliptic coordinates also
double u = omega + v;
double cosu = Math.Cos(u);
double sinu = Math.Sin(u);
details.HeliocentricRectangularEcliptical.X = r * (cosOmega * cosu - sinOmega * sinu * cosi);
details.HeliocentricRectangularEcliptical.Y = r * (sinOmega * cosu + cosOmega * sinu * cosi);
details.HeliocentricRectangularEcliptical.Z = r * sini * sinu;
details.HeliocentricEclipticLongitude = Math.Atan2(y, x);
details.HeliocentricEclipticLongitude = CT.M24(CT.R2D(details.HeliocentricEclipticLongitude) / 15);
details.HeliocentricEclipticLatitude = Math.Asin(z / r);
details.HeliocentricEclipticLatitude = CT.R2D(details.HeliocentricEclipticLatitude);
}
double psi = SunCoord.X + x;
double nu = SunCoord.Y + y;
double sigma = SunCoord.Z + z;
double Alpha = Math.Atan2(nu, psi);
Alpha = CT.R2D(Alpha);
double Delta = Math.Atan2(sigma, Math.Sqrt(psi * psi + nu * nu));
Delta = CT.R2D(Delta);
double Distance = Math.Sqrt(psi * psi + nu * nu + sigma * sigma);
if (j == 0)
{
details.TrueGeocentricRA = CT.M24(Alpha / 15);
details.TrueGeocentricDeclination = Delta;
details.TrueGeocentricDistance = Distance;
details.TrueGeocentricLightTime = ELL.DistanceToLightTime(Distance);
}
else
{
details.AstrometricGeocenticRA = CT.M24(Alpha / 15);
details.AstrometricGeocentricDeclination = Delta;
details.AstrometricGeocentricDistance = Distance;
details.AstrometricGeocentricLightTime = ELL.DistanceToLightTime(Distance);
double RES = Math.Sqrt(SunCoord.X * SunCoord.X + SunCoord.Y * SunCoord.Y + SunCoord.Z * SunCoord.Z);
details.Elongation = CT.R2D(Math.Acos((RES * RES + Distance * Distance - r * r) / (2 * RES * Distance)));
details.PhaseAngle = CT.R2D(Math.Acos((r * r + Distance * Distance - RES * RES) / (2 * r * Distance)));
}
if (j == 0) //Prepare for the next loop around
{
JD0 = JD - details.TrueGeocentricLightTime;
}
}
return(details);
}
