public static AAS2DCoordinate Equatorial2Topocentric(double Alpha, double Delta, double Distance, double Longitude, double Latitude, double Height, double JD)
{
double RhoSinThetaPrime = AASGlobe.RhoSinThetaPrime(Latitude, Height);
double RhoCosThetaPrime = AASGlobe.RhoCosThetaPrime(Latitude, Height);
//Calculate the Sidereal time
double theta = AASSidereal.ApparentGreenwichSiderealTime(JD);
//Convert to radians
Delta = AASCoordinateTransformation.DegreesToRadians(Delta);
double cosDelta = Math.Cos(Delta);
//Calculate the Parallax
double pi = Math.Asin(g_AAParallax_C1 / Distance);
double sinpi = Math.Sin(pi);
//Calculate the hour angle
double H = AASCoordinateTransformation.HoursToRadians(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);
AAS2DCoordinate Topocentric = new AAS2DCoordinate {
X = AASCoordinateTransformation.MapTo0To24Range(Alpha + AASCoordinateTransformation.RadiansToHours(DeltaAlpha)), Y = AASCoordinateTransformation.RadiansToDegrees(Math.Atan2((Math.Sin(Delta) - RhoSinThetaPrime * sinpi) * Math.Cos(DeltaAlpha), cosDelta - RhoCosThetaPrime * sinpi * cosH))
};
return(Topocentric);
}
public static AAS2DCoordinate PrecessEquatorialFK4(double Alpha, double Delta, double JD0, double JD)
{
double T = (JD0 - 2415020.3135) / 36524.2199;
double t = (JD - JD0) / 36524.2199;
double tsquared = t * t;
double tcubed = tsquared * t;
//Now convert to radians
Alpha = AASCoordinateTransformation.HoursToRadians(Alpha);
Delta = AASCoordinateTransformation.DegreesToRadians(Delta);
double sigma = AASCoordinateTransformation.DegreesToRadians(AASCoordinateTransformation.DMSToDegrees(0, 0, (2304.250 + 1.396 * T) * t + 0.302 * tsquared + 0.018 * tcubed));
double zeta = AASCoordinateTransformation.DegreesToRadians(AASCoordinateTransformation.DMSToDegrees(0, 0, 0.791 * tsquared + 0.001 * tcubed)) + sigma;
double phi = AASCoordinateTransformation.DegreesToRadians(AASCoordinateTransformation.DMSToDegrees(0, 0, (2004.682 - 0.853 * T) * t - 0.426 * tsquared - 0.042 * tcubed));
double A = Math.Cos(Delta) * Math.Sin(Alpha + sigma);
double B = Math.Cos(phi) * Math.Cos(Delta) * Math.Cos(Alpha + sigma) - Math.Sin(phi) * Math.Sin(Delta);
double C = Math.Sin(phi) * Math.Cos(Delta) * Math.Cos(Alpha + sigma) + Math.Cos(phi) * Math.Sin(Delta);
double DeltaAlpha = AASCoordinateTransformation.DMSToDegrees(0, 0, 0.0775 + 0.0850 * T);
AAS2DCoordinate value = new AAS2DCoordinate();
value.X = AASCoordinateTransformation.MapTo0To24Range(AASCoordinateTransformation.RadiansToHours(Math.Atan2(A, B) + zeta) + DeltaAlpha);
value.Y = AASCoordinateTransformation.RadiansToDegrees(Math.Asin(C));
return(value);
}
public static AAS2DCoordinate PrecessEquatorial(double Alpha, double Delta, double JD0, double JD)
{
double T = (JD0 - 2451545.0) / 36525;
double Tsquared = T * T;
double t = (JD - JD0) / 36525;
double tsquared = t * t;
double tcubed = tsquared * t;
//Now convert to radians
Alpha = AASCoordinateTransformation.HoursToRadians(Alpha);
Delta = AASCoordinateTransformation.DegreesToRadians(Delta);
double sigma = AASCoordinateTransformation.DegreesToRadians(AASCoordinateTransformation.DMSToDegrees(0, 0, (2306.2181 + 1.39656 * T - 0.000139 * Tsquared) * t + (0.30188 - 0.000344 * T) * tsquared + 0.017998 * tcubed));
double zeta = AASCoordinateTransformation.DegreesToRadians(AASCoordinateTransformation.DMSToDegrees(0, 0, (2306.2181 + 1.39656 * T - 0.000139 * Tsquared) * t + (1.09468 + 0.000066 * T) * tsquared + 0.018203 * tcubed));
double phi = AASCoordinateTransformation.DegreesToRadians(AASCoordinateTransformation.DMSToDegrees(0, 0, (2004.3109 - 0.8533 * T - 0.000217 * Tsquared) * t - (0.42665 + 0.000217 * T) * tsquared - 0.041833 * tcubed));
double A = Math.Cos(Delta) * Math.Sin(Alpha + sigma);
double B = Math.Cos(phi) * Math.Cos(Delta) * Math.Cos(Alpha + sigma) - Math.Sin(phi) * Math.Sin(Delta);
double C = Math.Sin(phi) * Math.Cos(Delta) * Math.Cos(Alpha + sigma) + Math.Cos(phi) * Math.Sin(Delta);
AAS2DCoordinate value = new AAS2DCoordinate();
value.X = AASCoordinateTransformation.MapTo0To24Range(AASCoordinateTransformation.RadiansToHours(Math.Atan2(A, B) + zeta));
value.Y = AASCoordinateTransformation.RadiansToDegrees(Math.Asin(C));
return(value);
}
public static AAS2DCoordinate AdjustPositionUsingMotionInSpace(double r, double DeltaR, double t, double Alpha, double Delta, double PMAlpha, double PMDelta)
{
//Convert DeltaR from km/s to Parsecs / Year
DeltaR /= 977792;
//Convert from seconds of time to Radians / Year
PMAlpha /= 13751;
//Convert from seconds of arc to Radians / Year
PMDelta /= 206265;
//Now convert to radians
Alpha = AASCoordinateTransformation.HoursToRadians(Alpha);
Delta = AASCoordinateTransformation.DegreesToRadians(Delta);
double x = r * Math.Cos(Delta) * Math.Cos(Alpha);
double y = r * Math.Cos(Delta) * Math.Sin(Alpha);
double z = r * Math.Sin(Delta);
double DeltaX = x / r * DeltaR - z * PMDelta * Math.Cos(Alpha) - y * PMAlpha;
double DeltaY = y / r * DeltaR - z * PMDelta * Math.Sin(Alpha) + x * PMAlpha;
double DeltaZ = z / r * DeltaR + r * PMDelta * Math.Cos(Delta);
x += t * DeltaX;
y += t * DeltaY;
z += t * DeltaZ;
AAS2DCoordinate value = new AAS2DCoordinate();
value.X = AASCoordinateTransformation.MapTo0To24Range(AASCoordinateTransformation.RadiansToHours(Math.Atan2(y, x)));
value.Y = AASCoordinateTransformation.RadiansToDegrees(Math.Atan2(z, Math.Sqrt(x * x + y * y)));
return(value);
}
public static double MeanGreenwichSiderealTime(double JD)
{
//Get the Julian day for the same day at midnight
long Year = 0;
long Month = 0;
long Day = 0;
long Hour = 0;
long Minute = 0;
double Second = 0;
AASDate date = new AASDate();
date.Set(JD, AASDate.AfterPapalReform(JD));
date.Get(ref Year, ref Month, ref Day, ref Hour, ref Minute, ref Second);
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 = AASCoordinateTransformation.DegreesToHours(Value);
return(AASCoordinateTransformation.MapTo0To24Range(Value));
}
public static double ApparentGreenwichSiderealTime(double JD)
{
double MeanObliquity = AASNutation.MeanObliquityOfEcliptic(JD);
double TrueObliquity = MeanObliquity + AASNutation.NutationInObliquity(JD) / 3600;
double NutationInLongitude = AASNutation.NutationInLongitude(JD);
double Value = MeanGreenwichSiderealTime(JD) + (NutationInLongitude * Math.Cos(AASCoordinateTransformation.DegreesToRadians(TrueObliquity)) / 54000);
return(AASCoordinateTransformation.MapTo0To24Range(Value));
}
private static void CorrectRAValuesForInterpolation(ref double Alpha1, ref double Alpha2, ref double Alpha3)
{
//Ensure the RA values are corrected for interpolation. Due to important Remark 2 by Meeus on Interopolation of RA values
Alpha1 = AASCoordinateTransformation.MapTo0To24Range(Alpha1);
Alpha2 = AASCoordinateTransformation.MapTo0To24Range(Alpha2);
Alpha3 = AASCoordinateTransformation.MapTo0To24Range(Alpha3);
if (Math.Abs(Alpha2 - Alpha1) > 12.0)
{
if (Alpha2 > Alpha1)
{
Alpha1 += 24;
}
else
{
Alpha2 += 24;
}
}
if (Math.Abs(Alpha3 - Alpha2) > 12.0)
{
if (Alpha3 > Alpha2)
{
Alpha2 += 24;
}
else
{
Alpha3 += 24;
}
}
if (Math.Abs(Alpha2 - Alpha1) > 12.0)
{
if (Alpha2 > Alpha1)
{
Alpha1 += 24;
}
else
{
Alpha2 += 24;
}
}
if (Math.Abs(Alpha3 - Alpha2) > 12.0)
{
if (Alpha3 > Alpha2)
{
Alpha2 += 24;
}
else
{
Alpha3 += 24;
}
}
}
public static AASNearParabolicObjectDetails Calculate(double JD, ref AASNearParabolicObjectElements elements, bool bHighPrecision)
{
double Epsilon = AASNutation.MeanObliquityOfEcliptic(elements.JDEquinox);
double JD0 = JD;
//What will be the return value
AASNearParabolicObjectDetails details = new AASNearParabolicObjectDetails();
Epsilon = AASCoordinateTransformation.DegreesToRadians(Epsilon);
double omega = AASCoordinateTransformation.DegreesToRadians(elements.omega);
double w = AASCoordinateTransformation.DegreesToRadians(elements.w);
double i = AASCoordinateTransformation.DegreesToRadians(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);
AAS3DCoordinate SunCoord = AASSun.EquatorialRectangularCoordinatesAnyEquinox(JD, elements.JDEquinox, bHighPrecision);
for (int j = 0; j < 2; j++)
{
double v = 0;
double r = 0;
CalulateTrueAnnomalyAndRadius(JD0, ref elements, ref v, ref r);
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 = w + 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 = AASCoordinateTransformation.MapTo0To360Range(AASCoordinateTransformation.RadiansToDegrees(Math.Atan2(details.HeliocentricRectangularEcliptical.Y, details.HeliocentricRectangularEcliptical.X)));
details.HeliocentricEclipticLatitude = AASCoordinateTransformation.RadiansToDegrees(Math.Asin(details.HeliocentricRectangularEcliptical.Z / r));
}
double psi = SunCoord.X + x;
double nu = SunCoord.Y + y;
double sigma = SunCoord.Z + z;
double Alpha = Math.Atan2(nu, psi);
Alpha = AASCoordinateTransformation.RadiansToDegrees(Alpha);
double Delta = Math.Atan2(sigma, Math.Sqrt(psi * psi + nu * nu));
Delta = AASCoordinateTransformation.RadiansToDegrees(Delta);
double Distance = Math.Sqrt(psi * psi + nu * nu + sigma * sigma);
if (j == 0)
{
details.TrueGeocentricRA = AASCoordinateTransformation.MapTo0To24Range(Alpha / 15);
details.TrueGeocentricDeclination = Delta;
details.TrueGeocentricDistance = Distance;
details.TrueGeocentricLightTime = AASElliptical.DistanceToLightTime(Distance);
}
else
{
details.AstrometricGeocentricRA = AASCoordinateTransformation.MapTo0To24Range(Alpha / 15);
details.AstrometricGeocentricDeclination = Delta;
details.AstrometricGeocentricDistance = Distance;
details.AstrometricGeocentricLightTime = AASElliptical.DistanceToLightTime(Distance);
double RES = Math.Sqrt(SunCoord.X * SunCoord.X + SunCoord.Y * SunCoord.Y + SunCoord.Z * SunCoord.Z);
details.Elongation = AASCoordinateTransformation.RadiansToDegrees(Math.Acos((RES * RES + Distance * Distance - r * r) / (2 * RES * Distance)));
details.PhaseAngle = AASCoordinateTransformation.RadiansToDegrees(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);
}