/// <summary>
/// Compute the eccentric anomaly 'E'
/// </summary>
/// <param name="eccentricity"></param>
/// <param name="meanAnomaly"></param>
/// <returns></returns>
internal static double GetEccentricAnomaly(double eccentricity, DegreeModel meanAnomaly)
{
var iteration = 0;
var maxIterationsiteration = 1000000;
var tolerance = Math.Pow(10, -10);
var eccentricAnomalyDegrees = new DegreeModel(DegreeHelper.RadiansToDegrees(eccentricity));
var result = meanAnomaly.Degrees + (eccentricAnomalyDegrees.Degrees * MathDegrees.Sin(meanAnomaly.Degrees));
while (iteration < maxIterationsiteration)
{
var deltaMeanAnomaly = meanAnomaly.Degrees - (result - (eccentricAnomalyDegrees.Degrees * MathDegrees.Sin(result)));
var deltaEccentricAnomaly = deltaMeanAnomaly / (1 - (eccentricity * MathDegrees.Cos(result)));
result = result + deltaEccentricAnomaly;
if (Math.Abs(deltaEccentricAnomaly) < tolerance)
{
return(result);
}
iteration++;
}
return(result);
}
public static LocationModel GetLocation(double centricDistance, DegreeModel ascendingNodeLongitude, DegreeModel perihelionOmega, DegreeModel trueAnomaly, DegreeModel inclination)
{
var x = centricDistance * (
(ascendingNodeLongitude.Cos() * MathDegrees.Cos(perihelionOmega.Degrees + trueAnomaly.Degrees)) -
(ascendingNodeLongitude.Sin() * inclination.Cos() * MathDegrees.Sin(perihelionOmega.Degrees + trueAnomaly.Degrees)));
var y = centricDistance * (
(ascendingNodeLongitude.Sin() * MathDegrees.Cos(perihelionOmega.Degrees + trueAnomaly.Degrees)) +
(ascendingNodeLongitude.Cos() * inclination.Cos() * MathDegrees.Sin(perihelionOmega.Degrees + trueAnomaly.Degrees)));
var z = centricDistance * (inclination.Sin() * MathDegrees.Sin(perihelionOmega.Degrees + trueAnomaly.Degrees));
return(new LocationModel(x, y, z));
}
private static double GetHourHorizon(
this CelestialObjectPositionModel celestialObjectPosition,
double latitudeDegrees,
double h0)
{
if (h0.EqualsWithinTolerance(0, 6))
{
return(DegreeHelper.RadiansToDegrees(
Math.Acos(
-MathDegrees.Tan(latitudeDegrees) *
MathDegrees.Tan(celestialObjectPosition.Declination))));
}
return(DegreeHelper.RadiansToDegrees(Math.Acos(
(MathDegrees.Sin(h0) - (MathDegrees.Sin(latitudeDegrees) * MathDegrees.Sin(celestialObjectPosition.Declination))) /
(MathDegrees.Cos(latitudeDegrees) * MathDegrees.Cos(celestialObjectPosition.Declination)))));
}
internal static SkyPositionModel GetSkyPosition(
double declination,
double latitude,
DateTimeOffset dateTimeOffset,
double siderealTime)
{
var azimuth =
DegreeHelper.RadiansToDegrees(
Math.Atan2(
MathDegrees.Sin(siderealTime),
(MathDegrees.Cos(siderealTime) * MathDegrees.Sin(latitude)) - (MathDegrees.Tan(declination) * MathDegrees.Cos(latitude))));
var height =
DegreeHelper.RadiansToDegrees(
Math.Asin(
(MathDegrees.Sin(latitude) * MathDegrees.Sin(declination)) +
(MathDegrees.Cos(latitude) * MathDegrees.Cos(declination) * MathDegrees.Cos(siderealTime))));
return(new SkyPositionModel(dateTimeOffset, height, azimuth));
}
public static double Cos(this DegreeModel model)
{
return(MathDegrees.Cos(model.Degrees));
}