private void ComputeFrameSynodic(RenderContext11 renderContext)
{
// A synodic frame is a rotating frame of reference in which
// the x-axis is the direction between the bodies in a two-body
// system. The origin is at the secondary body, and +x points
// in the direction opposite the primary. The z-axis is in the orbital
// plane and normal to x; it points in the direction of the instantaneous
// orbital velocity of the secondary.
// The origin is offset by then translation. The five libration points in a
// two-body system can be approximated by choosing different offsets. For
// example, the Sun-Earth L2 point is approximated by using x = 1,500,000 km, y = 0 and z = 0.
WorldMatrix = Matrix3d.Identity;
double localScale = (1 / renderContext.NominalRadius) * Scale * MeanRadius;
WorldMatrix.Scale(new Vector3d(localScale, localScale, localScale));
WorldMatrix.Rotate(Quaternion.RotationYawPitchRoll((float)((Heading) / 180.0 * Math.PI), (float)(Pitch / 180.0 * Math.PI), (float)(Roll / 180.0 * Math.PI)));
WorldMatrix.Translate(Translation / 6371.000);
// Currently we assume the Sun-Earth system
double jd = SpaceTimeController.JNow;
double B = CAACoordinateTransformation.DegreesToRadians(CAAEarth.EclipticLatitude(jd));
double L = CAACoordinateTransformation.DegreesToRadians(CAAEarth.EclipticLongitude(jd));
Vector3d eclPos = new Vector3d(Math.Cos(L) * Math.Cos(B), Math.Sin(L) * Math.Cos(B), Math.Sin(B));
// Just approximate the orbital velocity for now
Vector3d eclVel = Vector3d.Cross(eclPos, new Vector3d(0.0, 0.0, 1.0));
eclVel.Normalize();
// Convert to WWT's coordinate convention by swapping Y and Z
eclPos = new Vector3d(eclPos.X, eclPos.Z, eclPos.Y);
eclVel = new Vector3d(eclVel.X, eclVel.Z, eclVel.Y);
Vector3d xaxis = eclPos;
Vector3d yaxis = Vector3d.Cross(eclVel, eclPos);
Vector3d zaxis = eclVel;
Matrix3d rotation = new Matrix3d(xaxis.X, yaxis.X, zaxis.X, 0, xaxis.Y, yaxis.Y, zaxis.Y, 0, xaxis.Z, yaxis.Z, zaxis.Z, 0, 0, 0, 0, 1);
// Convert from ecliptic to J2000 EME (equatorial) system
double earthObliquity = CAACoordinateTransformation.DegreesToRadians(Coordinates.MeanObliquityOfEcliptic(jd));
rotation = rotation * Matrix3d.RotationX(-earthObliquity);
WorldMatrix.Multiply(rotation);
}
//Static methods
//////////////////////////////// Implementation ///////////////////////////////
public static CAAPhysicalSunDetails Calculate(double JD)
{
double theta = CAACoordinateTransformation.MapTo0To360Range((JD - 2398220) * 360 / 25.38);
double I = 7.25;
double K = 73.6667 + 1.3958333 * (JD - 2396758) / 36525;
//Calculate the apparent longitude of the sun (excluding the effect of nutation)
double L = CAAEarth.EclipticLongitude(JD);
double R = CAAEarth.RadiusVector(JD);
double SunLong = L + 180 - CAACoordinateTransformation.DMSToDegrees(0, 0, 20.4898 / R);
double SunLongDash = SunLong + CAACoordinateTransformation.DMSToDegrees(0, 0, CAANutation.NutationInLongitude(JD));
double epsilon = CAANutation.TrueObliquityOfEcliptic(JD);
//Convert to radians
epsilon = CAACoordinateTransformation.DegreesToRadians(epsilon);
SunLong = CAACoordinateTransformation.DegreesToRadians(SunLong);
SunLongDash = CAACoordinateTransformation.DegreesToRadians(SunLongDash);
K = CAACoordinateTransformation.DegreesToRadians(K);
I = CAACoordinateTransformation.DegreesToRadians(I);
theta = CAACoordinateTransformation.DegreesToRadians(theta);
double x = Math.Atan(-Math.Cos(SunLong) * Math.Tan(epsilon));
double y = Math.Atan(-Math.Cos(SunLong - K) * Math.Tan(I));
CAAPhysicalSunDetails details = new CAAPhysicalSunDetails();
details.P = CAACoordinateTransformation.RadiansToDegrees(x + y);
details.B0 = CAACoordinateTransformation.RadiansToDegrees(Math.Asin(Math.Sin(SunLong - K) * Math.Sin(I)));
double eta = Math.Atan(Math.Tan(SunLong - K) * Math.Cos(I));
details.L0 = CAACoordinateTransformation.MapTo0To360Range(CAACoordinateTransformation.RadiansToDegrees(eta - theta));
return(details);
}
//Static methods
//////////////////////////////// Implementation ///////////////////////////////
public static CAAPhysicalJupiterDetails Calculate(double JD)
{
//What will be the return value
CAAPhysicalJupiterDetails details = new CAAPhysicalJupiterDetails();
//Step 1
double d = JD - 2433282.5;
double T1 = d / 36525;
double alpha0 = 268.00 + 0.1061 * T1;
double alpha0rad = CT.D2R(alpha0);
double delta0 = 64.50 - 0.0164 * T1;
double delta0rad = CT.D2R(delta0);
//Step 2
double W1 = CT.M360(17.710 + 877.90003539 * d);
double W2 = CT.M360(16.838 + 870.27003539 * d);
//Step 3
double l0 = CAAEarth.EclipticLongitude(JD);
double l0rad = CT.D2R(l0);
double b0 = CAAEarth.EclipticLatitude(JD);
double b0rad = CT.D2R(b0);
double R = CAAEarth.RadiusVector(JD);
//Step 4
double l = CAAJupiter.EclipticLongitude(JD);
double lrad = CT.D2R(l);
double b = CAAJupiter.EclipticLatitude(JD);
double brad = CT.D2R(b);
double r = CAAJupiter.RadiusVector(JD);
//Step 5
double x = r * Math.Cos(brad) * Math.Cos(lrad) - R * Math.Cos(l0rad);
double y = r * Math.Cos(brad) * Math.Sin(lrad) - R * Math.Sin(l0rad);
double z = r * Math.Sin(brad) - R * Math.Sin(b0rad);
double DELTA = Math.Sqrt(x * x + y * y + z * z);
//Step 6
l -= 0.012990 * DELTA / (r * r);
lrad = CT.D2R(l);
//Step 7
x = r * Math.Cos(brad) * Math.Cos(lrad) - R * Math.Cos(l0rad);
y = r * Math.Cos(brad) * Math.Sin(lrad) - R * Math.Sin(l0rad);
z = r * Math.Sin(brad) - R * Math.Sin(b0rad);
DELTA = Math.Sqrt(x * x + y * y + z * z);
//Step 8
double e0 = CAANutation.MeanObliquityOfEcliptic(JD);
double e0rad = CT.D2R(e0);
//Step 9
double alphas = Math.Atan2(Math.Cos(e0rad) * Math.Sin(lrad) - Math.Sin(e0rad) * Math.Tan(brad), Math.Cos(lrad));
double deltas = Math.Asin(Math.Cos(e0rad) * Math.Sin(brad) + Math.Sin(e0rad) * Math.Cos(brad) * Math.Sin(lrad));
//Step 10
details.DS = CT.R2D(Math.Asin(-Math.Sin(delta0rad) * Math.Sin(deltas) - Math.Cos(delta0rad) * Math.Cos(deltas) * Math.Cos(alpha0rad - alphas)));
//Step 11
double u = y * Math.Cos(e0rad) - z * Math.Sin(e0rad);
double v = y * Math.Sin(e0rad) + z * Math.Cos(e0rad);
double alpharad = Math.Atan2(u, x);
double alpha = CT.R2D(alpharad);
double deltarad = Math.Atan2(v, Math.Sqrt(x * x + u * u));
double delta = CT.R2D(deltarad);
double xi = Math.Atan2(Math.Sin(delta0rad) * Math.Cos(deltarad) * Math.Cos(alpha0rad - alpharad) - Math.Sin(deltarad) * Math.Cos(delta0rad), Math.Cos(deltarad) * Math.Sin(alpha0rad - alpharad));
//Step 12
details.DE = CT.R2D(Math.Asin(-Math.Sin(delta0rad) * Math.Sin(deltarad) - Math.Cos(delta0rad) * Math.Cos(deltarad) * Math.Cos(alpha0rad - alpharad)));
//Step 13
details.Geometricw1 = CT.M360(W1 - CT.R2D(xi) - 5.07033 * DELTA);
details.Geometricw2 = CT.M360(W2 - CT.R2D(xi) - 5.02626 * DELTA);
//Step 14
double C = 57.2958 * (2 * r * DELTA + R * R - r * r - DELTA * DELTA) / (4 * r * DELTA);
if (Math.Sin(lrad - l0rad) > 0)
{
details.Apparentw1 = CT.M360(details.Geometricw1 + C);
details.Apparentw2 = CT.M360(details.Geometricw2 + C);
}
else
{
details.Apparentw1 = CT.M360(details.Geometricw1 - C);
details.Apparentw2 = CT.M360(details.Geometricw2 - C);
}
//Step 15
double NutationInLongitude = CAANutation.NutationInLongitude(JD);
double NutationInObliquity = CAANutation.NutationInObliquity(JD);
e0 += NutationInObliquity / 3600;
e0rad = CT.D2R(e0);
//Step 16
alpha += 0.005693 * (Math.Cos(alpharad) * Math.Cos(l0rad) * Math.Cos(e0rad) + Math.Sin(alpharad) * Math.Sin(l0rad)) / Math.Cos(deltarad);
alpha = CT.M360(alpha);
alpharad = CT.D2R(alpha);
delta += 0.005693 * (Math.Cos(l0rad) * Math.Cos(e0rad) * (Math.Tan(e0rad) * Math.Cos(deltarad) - Math.Sin(alpharad) * Math.Sin(deltarad)) + Math.Cos(alpharad) * Math.Sin(deltarad) * Math.Sin(l0rad));
deltarad = CT.D2R(delta);
//Step 17
double NutationRA = CAANutation.NutationInRightAscension(alpha / 15, delta, e0, NutationInLongitude, NutationInObliquity);
double alphadash = alpha + NutationRA / 3600;
double alphadashrad = CT.D2R(alphadash);
double NutationDec = CAANutation.NutationInDeclination(alpha / 15, delta, e0, NutationInLongitude, NutationInObliquity);
double deltadash = delta + NutationDec / 3600;
double deltadashrad = CT.D2R(deltadash);
NutationRA = CAANutation.NutationInRightAscension(alpha0 / 15, delta0, e0, NutationInLongitude, NutationInObliquity);
double alpha0dash = alpha0 + NutationRA / 3600;
double alpha0dashrad = CT.D2R(alpha0dash);
NutationDec = CAANutation.NutationInDeclination(alpha0 / 15, delta0, e0, NutationInLongitude, NutationInObliquity);
double delta0dash = delta0 + NutationDec / 3600;
double delta0dashrad = CT.D2R(delta0dash);
//Step 18
details.P = CT.M360(CT.R2D(Math.Atan2(Math.Cos(delta0dashrad) * Math.Sin(alpha0dashrad - alphadashrad), Math.Sin(delta0dashrad) * Math.Cos(deltadashrad) - Math.Cos(delta0dashrad) * Math.Sin(deltadashrad) * Math.Cos(alpha0dashrad - alphadashrad))));
return(details);
}
//Static methods
//////////////////////////////// Implementation ///////////////////////////////
public static CAASaturnRingDetails Calculate(double JD)
{
//What will be the return value
CAASaturnRingDetails details = new CAASaturnRingDetails();
double T = (JD - 2451545) / 36525;
double T2 = T * T;
//Step 1. Calculate the inclination of the plane of the ring and the longitude of the ascending node referred to the ecliptic and mean equinox of the date
double i = 28.075216 - 0.012998 * T + 0.000004 * T2;
double irad = CT.D2R(i);
double omega = 169.508470 + 1.394681 * T + 0.000412 * T2;
double omegarad = CT.D2R(omega);
//Step 2. Calculate the heliocentric longitude, latitude and radius vector of the Earth in the FK5 system
double l0 = CAAEarth.EclipticLongitude(JD);
double b0 = CAAEarth.EclipticLatitude(JD);
l0 += CAAFK5.CorrectionInLongitude(l0, b0, JD);
double l0rad = CT.D2R(l0);
b0 += CAAFK5.CorrectionInLatitude(l0, JD);
double b0rad = CT.D2R(b0);
double R = CAAEarth.RadiusVector(JD);
//Step 3. Calculate the corresponding coordinates l,b,r for Saturn but for the instance t-lightraveltime
double DELTA = 9;
double PreviousEarthLightTravelTime = 0;
double EarthLightTravelTime = ELL.DistanceToLightTime(DELTA);
double JD1 = JD - EarthLightTravelTime;
bool bIterate = true;
double x = 0;
double y = 0;
double z = 0;
double l = 0;
double b = 0;
double r = 0;
while (bIterate)
{
//Calculate the position of Saturn
l = CAASaturn.EclipticLongitude(JD1);
b = CAASaturn.EclipticLatitude(JD1);
l += CAAFK5.CorrectionInLongitude(l, b, JD1);
b += CAAFK5.CorrectionInLatitude(l, JD1);
double lrad = CT.D2R(l);
double brad = CT.D2R(b);
r = CAASaturn.RadiusVector(JD1);
//Step 4
x = r * Math.Cos(brad) * Math.Cos(lrad) - R * Math.Cos(l0rad);
y = r * Math.Cos(brad) * Math.Sin(lrad) - R * Math.Sin(l0rad);
z = r * Math.Sin(brad) - R * Math.Sin(b0rad);
DELTA = Math.Sqrt(x * x + y * y + z * z);
EarthLightTravelTime = ELL.DistanceToLightTime(DELTA);
//Prepare for the next loop around
bIterate = (Math.Abs(EarthLightTravelTime - PreviousEarthLightTravelTime) > 2E-6); //2E-6 corresponds to 0.17 of a second
if (bIterate)
{
JD1 = JD - EarthLightTravelTime;
PreviousEarthLightTravelTime = EarthLightTravelTime;
}
}
//Step 5. Calculate Saturn's geocentric Longitude and Latitude
double lambda = Math.Atan2(y, x);
double beta = Math.Atan2(z, Math.Sqrt(x * x + y * y));
//Step 6. Calculate B, a and b
details.B = Math.Asin(Math.Sin(irad) * Math.Cos(beta) * Math.Sin(lambda - omegarad) - Math.Cos(irad) * Math.Sin(beta));
details.a = 375.35 / DELTA;
details.b = details.a * Math.Sin(Math.Abs(details.B));
details.B = CT.R2D(details.B);
//Step 7. Calculate the longitude of the ascending node of Saturn's orbit
double N = 113.6655 + 0.8771 * T;
double Nrad = CT.D2R(N);
double ldash = l - 0.01759 / r;
double ldashrad = CT.D2R(ldash);
double bdash = b - 0.000764 * Math.Cos(ldashrad - Nrad) / r;
double bdashrad = CT.D2R(bdash);
//Step 8. Calculate Bdash
details.Bdash = CT.R2D(Math.Asin(Math.Sin(irad) * Math.Cos(bdashrad) * Math.Sin(ldashrad - omegarad) - Math.Cos(irad) * Math.Sin(bdashrad)));
//Step 9. Calculate DeltaU
double U1 = Math.Atan2(Math.Sin(irad) * Math.Sin(bdashrad) + Math.Cos(irad) * Math.Cos(bdashrad) * Math.Sin(ldashrad - omegarad), Math.Cos(bdashrad) * Math.Cos(ldashrad - omegarad));
double U2 = Math.Atan2(Math.Sin(irad) * Math.Sin(beta) + Math.Cos(irad) * Math.Cos(beta) * Math.Sin(lambda - omegarad), Math.Cos(beta) * Math.Cos(lambda - omegarad));
details.DeltaU = CT.R2D(Math.Abs(U1 - U2));
//Step 10. Calculate the Nutations
double Obliquity = CAANutation.TrueObliquityOfEcliptic(JD);
double NutationInLongitude = CAANutation.NutationInLongitude(JD);
//Step 11. Calculate the Ecliptical longitude and latitude of the northern pole of the ring plane
double lambda0 = omega - 90;
double beta0 = 90 - i;
//Step 12. Correct lambda and beta for the aberration of Saturn
lambda += CT.D2R(0.005693 * Math.Cos(l0rad - lambda) / Math.Cos(beta));
beta += CT.D2R(0.005693 * Math.Sin(l0rad - lambda) * Math.Sin(beta));
//Step 13. Add nutation in longitude to lambda0 and lambda
//double NLrad = CAACoordinateTransformation::DegreesToRadians(NutationInLongitude/3600);
lambda = CT.R2D(lambda);
lambda += NutationInLongitude / 3600;
lambda = CT.M360(lambda);
lambda0 += NutationInLongitude / 3600;
lambda0 = CT.M360(lambda0);
//Step 14. Convert to equatorial coordinates
beta = CT.R2D(beta);
COR GeocentricEclipticSaturn = CT.Ec2Eq(lambda, beta, Obliquity);
double alpha = CT.H2R(GeocentricEclipticSaturn.X);
double delta = CT.D2R(GeocentricEclipticSaturn.Y);
COR GeocentricEclipticNorthPole = CT.Ec2Eq(lambda0, beta0, Obliquity);
double alpha0 = CT.H2R(GeocentricEclipticNorthPole.X);
double delta0 = CT.D2R(GeocentricEclipticNorthPole.Y);
//Step 15. Calculate the Position angle
details.P = CT.R2D(Math.Atan2(Math.Cos(delta0) * Math.Sin(alpha0 - alpha), Math.Sin(delta0) * Math.Cos(delta) - Math.Cos(delta0) * Math.Sin(delta) * Math.Cos(alpha0 - alpha)));
return(details);
}
public static EPD Calculate(double JD, EO @object)
{
//What will the the return value
EPD details = new EPD();
double JD0 = JD;
double L0 = 0;
double B0 = 0;
double R0 = 0;
double cosB0 = 0;
if (@object != EO.SUN)
{
L0 = CAAEarth.EclipticLongitude(JD0);
B0 = CAAEarth.EclipticLatitude(JD0);
R0 = CAAEarth.RadiusVector(JD0);
L0 = CT.D2R(L0);
B0 = CT.D2R(B0);
cosB0 = Math.Cos(B0);
}
//Calculate the initial values
double L = 0;
double B = 0;
double R = 0;
double Lrad;
double Brad;
double cosB;
double cosL;
double x;
double y;
double z;
bool bRecalc = true;
bool bFirstRecalc = true;
double LPrevious = 0;
double BPrevious = 0;
double RPrevious = 0;
while (bRecalc)
{
switch (@object)
{
case EO.SUN:
{
L = CAASun.GeometricEclipticLongitude(JD0);
B = CAASun.GeometricEclipticLatitude(JD0);
R = CAAEarth.RadiusVector(JD0);
break;
}
case EO.MERCURY:
{
L = CAAMercury.EclipticLongitude(JD0);
B = CAAMercury.EclipticLatitude(JD0);
R = CAAMercury.RadiusVector(JD0);
break;
}
case EO.VENUS:
{
L = CAAVenus.EclipticLongitude(JD0);
B = CAAVenus.EclipticLatitude(JD0);
R = CAAVenus.RadiusVector(JD0);
break;
}
case EO.MARS:
{
L = CAAMars.EclipticLongitude(JD0);
B = CAAMars.EclipticLatitude(JD0);
R = CAAMars.RadiusVector(JD0);
break;
}
case EO.JUPITER:
{
L = CAAJupiter.EclipticLongitude(JD0);
B = CAAJupiter.EclipticLatitude(JD0);
R = CAAJupiter.RadiusVector(JD0);
break;
}
case EO.SATURN:
{
L = CAASaturn.EclipticLongitude(JD0);
B = CAASaturn.EclipticLatitude(JD0);
R = CAASaturn.RadiusVector(JD0);
break;
}
case EO.URANUS:
{
L = CAAUranus.EclipticLongitude(JD0);
B = CAAUranus.EclipticLatitude(JD0);
R = CAAUranus.RadiusVector(JD0);
break;
}
case EO.NEPTUNE:
{
L = CAANeptune.EclipticLongitude(JD0);
B = CAANeptune.EclipticLatitude(JD0);
R = CAANeptune.RadiusVector(JD0);
break;
}
case EO.PLUTO:
{
L = CAAPluto.EclipticLongitude(JD0);
B = CAAPluto.EclipticLatitude(JD0);
R = CAAPluto.RadiusVector(JD0);
break;
}
default:
{
Debug.Assert(false);
break;
}
}
if (!bFirstRecalc)
{
bRecalc = ((Math.Abs(L - LPrevious) > 0.00001) || (Math.Abs(B - BPrevious) > 0.00001) || (Math.Abs(R - RPrevious) > 0.000001));
LPrevious = L;
BPrevious = B;
RPrevious = R;
}
else
{
bFirstRecalc = false;
}
//Calculate the new value
if (bRecalc)
{
double distance = 0;
if (@object != EO.SUN)
{
Lrad = CT.D2R(L);
Brad = CT.D2R(B);
cosB = Math.Cos(Brad);
cosL = Math.Cos(Lrad);
x = R * cosB * cosL - R0 * cosB0 * Math.Cos(L0);
y = R * cosB * Math.Sin(Lrad) - R0 * cosB0 * Math.Sin(L0);
z = R * Math.Sin(Brad) - R0 * Math.Sin(B0);
distance = Math.Sqrt(x * x + y * y + z * z);
}
else
{
distance = R; //Distance to the sun from the earth is in fact the radius vector
}
//Prepare for the next loop around
JD0 = JD - ELL.DistanceToLightTime(distance);
}
}
Lrad = CT.D2R(L);
Brad = CT.D2R(B);
cosB = Math.Cos(Brad);
cosL = Math.Cos(Lrad);
x = R * cosB * cosL - R0 * cosB0 * Math.Cos(L0);
y = R * cosB * Math.Sin(Lrad) - R0 * cosB0 * Math.Sin(L0);
z = R * Math.Sin(Brad) - R0 * Math.Sin(B0);
double x2 = x * x;
double y2 = y * y;
details.ApparentGeocentricLatitude = CT.R2D(Math.Atan2(z, Math.Sqrt(x2 + y2)));
details.ApparentGeocentricDistance = Math.Sqrt(x2 + y2 + z * z);
details.ApparentGeocentricLongitude = CT.M360(CT.R2D(Math.Atan2(y, x)));
details.ApparentLightTime = ELL.DistanceToLightTime(details.ApparentGeocentricDistance);
//Adjust for Aberration
COR Aberration = ABR.EclipticAberration(details.ApparentGeocentricLongitude, details.ApparentGeocentricLatitude, JD);
details.ApparentGeocentricLongitude += Aberration.X;
details.ApparentGeocentricLatitude += Aberration.Y;
//convert to the FK5 system
double DeltaLong = CAAFK5.CorrectionInLongitude(details.ApparentGeocentricLongitude, details.ApparentGeocentricLatitude, JD);
details.ApparentGeocentricLatitude += CAAFK5.CorrectionInLatitude(details.ApparentGeocentricLongitude, JD);
details.ApparentGeocentricLongitude += DeltaLong;
//Correct for nutation
double NutationInLongitude = CAANutation.NutationInLongitude(JD);
double Epsilon = CAANutation.TrueObliquityOfEcliptic(JD);
details.ApparentGeocentricLongitude += CT.DMS2D(0, 0, NutationInLongitude);
//Convert to RA and Dec
COR ApparentEqu = CT.Ec2Eq(details.ApparentGeocentricLongitude, details.ApparentGeocentricLatitude, Epsilon);
details.ApparentGeocentricRA = ApparentEqu.X;
details.ApparentGeocentricDeclination = ApparentEqu.Y;
return(details);
}
//Static methods
//////////////////////////////// Implementation ///////////////////////////////
public static CAAPhysicalMarsDetails Calculate(double JD)
{
//What will be the return value
CAAPhysicalMarsDetails details = new CAAPhysicalMarsDetails();
//Step 1
double T = (JD - 2451545) / 36525;
double Lambda0 = 352.9065 + 1.17330 * T;
double Lambda0rad = CT.D2R(Lambda0);
double Beta0 = 63.2818 - 0.00394 * T;
double Beta0rad = CT.D2R(Beta0);
//Step 2
double l0 = CAAEarth.EclipticLongitude(JD);
double l0rad = CT.D2R(l0);
double b0 = CAAEarth.EclipticLatitude(JD);
double b0rad = CT.D2R(b0);
double R = CAAEarth.RadiusVector(JD);
double PreviousLightTravelTime = 0;
double LightTravelTime = 0;
double x = 0;
double y = 0;
double z = 0;
bool bIterate = true;
double DELTA = 0;
double l = 0;
double lrad = 0;
double b = 0;
double brad = 0;
double r = 0;
while (bIterate)
{
double JD2 = JD - LightTravelTime;
//Step 3
l = CAAMars.EclipticLongitude(JD2);
lrad = CT.D2R(l);
b = CAAMars.EclipticLatitude(JD2);
brad = CT.D2R(b);
r = CAAMars.RadiusVector(JD2);
//Step 4
x = r * Math.Cos(brad) * Math.Cos(lrad) - R * Math.Cos(l0rad);
y = r * Math.Cos(brad) * Math.Sin(lrad) - R * Math.Sin(l0rad);
z = r * Math.Sin(brad) - R * Math.Sin(b0rad);
DELTA = Math.Sqrt(x * x + y * y + z * z);
LightTravelTime = ELL.DistanceToLightTime(DELTA);
//Prepare for the next loop around
bIterate = (Math.Abs(LightTravelTime - PreviousLightTravelTime) > 2E-6); //2E-6 correponds to 0.17 of a second
if (bIterate)
{
PreviousLightTravelTime = LightTravelTime;
}
}
//Step 5
double lambdarad = Math.Atan2(y, x);
double lambda = CT.R2D(lambdarad);
double betarad = Math.Atan2(z, Math.Sqrt(x * x + y * y));
double beta = CT.R2D(betarad);
//Step 6
details.DE = CT.R2D(Math.Asin(-Math.Sin(Beta0rad) * Math.Sin(betarad) - Math.Cos(Beta0rad) * Math.Cos(betarad) * Math.Cos(Lambda0rad - lambdarad)));
//Step 7
double N = 49.5581 + 0.7721 * T;
double Nrad = CT.D2R(N);
double ldash = l - 0.00697 / r;
double ldashrad = CT.D2R(ldash);
double bdash = b - 0.000225 * (Math.Cos(lrad - Nrad) / r);
double bdashrad = CT.D2R(bdash);
//Step 8
details.DS = CT.R2D(Math.Asin(-Math.Sin(Beta0rad) * Math.Sin(bdashrad) - Math.Cos(Beta0rad) * Math.Cos(bdashrad) * Math.Cos(Lambda0rad - ldashrad)));
//Step 9
double W = CT.M360(11.504 + 350.89200025 * (JD - LightTravelTime - 2433282.5));
//Step 10
double e0 = CAANutation.MeanObliquityOfEcliptic(JD);
double e0rad = CT.D2R(e0);
COR PoleEquatorial = CT.Ec2Eq(Lambda0, Beta0, e0);
double alpha0rad = CT.H2R(PoleEquatorial.X);
double delta0rad = CT.D2R(PoleEquatorial.Y);
//Step 11
double u = y * Math.Cos(e0rad) - z * Math.Sin(e0rad);
double v = y * Math.Sin(e0rad) + z * Math.Cos(e0rad);
double alpharad = Math.Atan2(u, x);
double alpha = CT.R2H(alpharad);
double deltarad = Math.Atan2(v, Math.Sqrt(x * x + u * u));
double delta = CT.R2D(deltarad);
double xi = Math.Atan2(Math.Sin(delta0rad) * Math.Cos(deltarad) * Math.Cos(alpha0rad - alpharad) - Math.Sin(deltarad) * Math.Cos(delta0rad), Math.Cos(deltarad) * Math.Sin(alpha0rad - alpharad));
//Step 12
details.w = CT.M360(W - CT.R2D(xi));
//Step 13
double NutationInLongitude = CAANutation.NutationInLongitude(JD);
double NutationInObliquity = CAANutation.NutationInObliquity(JD);
//Step 14
lambda += 0.005693 * Math.Cos(l0rad - lambdarad) / Math.Cos(betarad);
beta += 0.005693 * Math.Sin(l0rad - lambdarad) * Math.Sin(betarad);
//Step 15
Lambda0 += NutationInLongitude / 3600;
Lambda0rad = CT.D2R(Lambda0);
lambda += NutationInLongitude / 3600;
lambdarad = CT.D2R(lambda);
e0 += NutationInObliquity / 3600;
e0rad = CT.D2R(e0rad);
//Step 16
COR ApparentPoleEquatorial = CT.Ec2Eq(Lambda0, Beta0, e0);
double alpha0dash = CT.H2R(ApparentPoleEquatorial.X);
double delta0dash = CT.D2R(ApparentPoleEquatorial.Y);
COR ApparentMars = CT.Ec2Eq(lambda, beta, e0);
double alphadash = CT.H2R(ApparentMars.X);
double deltadash = CT.D2R(ApparentMars.Y);
//Step 17
details.P = CT.M360(CT.R2D(Math.Atan2(Math.Cos(delta0dash) * Math.Sin(alpha0dash - alphadash), Math.Sin(delta0dash) * Math.Cos(deltadash) - Math.Cos(delta0dash) * Math.Sin(deltadash) * Math.Cos(alpha0dash - alphadash))));
//Step 18
double SunLambda = CAASun.GeometricEclipticLongitude(JD);
double SunBeta = CAASun.GeometricEclipticLatitude(JD);
COR SunEquatorial = CT.Ec2Eq(SunLambda, SunBeta, e0);
details.X = MIFR.PositionAngle(SunEquatorial.X, SunEquatorial.Y, alpha, delta);
//Step 19
details.d = 9.36 / DELTA;
details.k = IFR.IlluminatedFraction2(r, R, DELTA);
details.q = (1 - details.k) * details.d;
return(details);
}
//Static methods
//////////////////////////// Implementation ///////////////////////////////////
public static double GeometricEclipticLongitude(double JD)
{
return(CAACoordinateTransformation.MapTo0To360Range(CAAEarth.EclipticLongitude(JD) + 180));
}
//Static methods
//////////////////////////// Implementation ///////////////////////////////////
public static double GeometricEclipticLongitude(double JD)
{
return(CT.M360(CAAEarth.EclipticLongitude(JD) + 180));
}
