private ICollection <AstroEvent> FindSolarEclipses(AstroEventsContext context)
{
List <AstroEvent> events = new List <AstroEvent>();
int ln = LunarEphem.Lunation(context.From, LunationSystem.Meeus);
do
{
SolarEclipse eclipse = GetNearestSolarEclipse(ln, next: true, saros: false);
double jd = eclipse.JulianDayMaximum;
if (jd <= context.To)
{
var pbe = GetBesselianElements(jd);
var localCirc = SolarEclipses.LocalCircumstances(pbe, context.GeoLocation);
string type = Text.Get($"SolarEclipse.Type.{eclipse.EclipseType}");
string subtype = eclipse.IsNonCentral ? $" {Text.Get("SolarEclipse.Type.NoCentral")}" : "";
string phase = eclipse.EclipseType == SolarEclipseType.Partial ? $" ({Text.Get("SolarEclipse.MaxPhase")} {Formatters.Phase.Format(eclipse.Magnitude)})" : "";
double jdMax = localCirc.MaxMagnitude > 0 ? localCirc.Maximum.JulianDay : jd;
string localVisibility = GetLocalVisibilityString(eclipse, localCirc);
events.Add(new AstroEvent(jdMax, Text.Get("SolarEclipse.Event", ("type", type), ("subtype", subtype), ("phase", phase), ("localVisibility", localVisibility)), sun, moon));
ln = eclipse.MeeusLunationNumber + 1;
}
else
{
break;
}
}while (true);
return(events);
}
/// <inheritdoc />
public SolarEclipse GetNearestSolarEclipse(int ln, bool next, bool saros)
{
do
{
ln += (next ? 1 : -1) * (saros ? 223 : 1);
var eclipse = SolarEclipses.NearestEclipse(ln, next);
if (eclipse.IsUncertain)
{
var pbe = GetBesselianElements(eclipse.JulianDayMaximum);
var be = pbe.GetInstantBesselianElements(eclipse.JulianDayMaximum);
bool isExist = Math.Sqrt(be.X * be.X + be.Y * be.Y) - be.L1 <= 0.999;
if (isExist)
{
eclipse.IsUncertain = false;
return(eclipse);
}
else
{
continue;
}
}
else
{
return(eclipse);
}
}while (true);
}
/// <inheritdoc/>
public ICollection <SolarEclipseLocalCircumstances> FindLocalCircumstancesForCities(PolynomialBesselianElements be, ICollection <CrdsGeographical> cities, CancellationToken?cancelToken = null, IProgress <double> progress = null)
{
return(cities
.Distinct()
.Select(c => SolarEclipses.LocalCircumstances(be, c))
.ToArray());
}
public void FindInstantBesselianElements()
{
// 11 Aug 1999, 11:00:00 TDT
// Besselian elements are taken from
// https://eclipse.gsfc.nasa.gov/SEsearch/SEdata.php?Ecl=+19990811
// Sun and Moon geocentric positions are taken
// from NASA horizons tool
// https://ssd.jpl.nasa.gov/horizons.cgi
var position = new SunMoonPosition()
{
JulianDay = 2451401.958333333,
Sun = new CrdsEquatorial(new HMS("09h 23m 11.27s"), new DMS("+15* 19' 30.1''")),
Moon = new CrdsEquatorial(new HMS("09h 23m 30.71s"), new DMS("+15* 48' 50.3''")),
DistanceSun = 1.5162934697E+08 / 6371.0,
DistanceMoon = 3.7330565613E+05 / 6371.0
};
var elements = SolarEclipses.BesselianElements(position);
Assert.AreEqual(15.32734, elements.D, 1e-2);
Assert.AreEqual(343.68741, elements.Mu, 1e-1);
Assert.AreEqual(0.070042, elements.X, 1e-2);
Assert.AreEqual(0.502841, elements.Y, 1e-2);
Assert.AreEqual(0.542469, elements.L1, 1e-2);
Assert.AreEqual(-0.003650, elements.L2, 1e-2);
}
public void FindNearestSolarEclipse()
{
double jd = new Date(1993, 5, 21).ToJulianDay();
SolarEclipse eclipse = SolarEclipses.NearestEclipse(jd, true);
Assert.AreEqual(2449129.0979, eclipse.JulianDayMaximum, TimeSpan.FromMinutes(0.36).TotalDays);
Assert.AreEqual(SolarEclipseType.Partial, eclipse.EclipseType);
Assert.AreEqual(0.740, eclipse.Magnitude, 1e-3);
}
public void ProjectionTests()
{
{
double d = 15.32558;
double mu = 345.88554;
CrdsGeographical g = new CrdsGeographical(-26.71875, 44.66865);
Vector v = SolarEclipses.ProjectOnFundamentalPlane(g, d, mu);
CrdsGeographical g0 = SolarEclipses.ProjectOnEarth(new System.Drawing.PointF((float)v.X, (float)v.Y), d, mu);
Assert.AreEqual(g.Latitude, g0.Latitude, 1e-5);
Assert.AreEqual(g.Longitude, g0.Longitude, 1e-5);
}
{
double d = -23.25608;
double mu = 48.57292;
CrdsGeographical g = new CrdsGeographical(97.20703, -28.22697);
Vector v = SolarEclipses.ProjectOnFundamentalPlane(g, d, mu);
CrdsGeographical g0 = SolarEclipses.ProjectOnEarth(new System.Drawing.PointF((float)v.X, (float)v.Y), d, mu);
Assert.AreEqual(g.Latitude, g0.Latitude, 1e-5);
Assert.AreEqual(g.Longitude, g0.Longitude, 1e-5);
}
}
/// <inheritdoc/>
public ICollection <SolarEclipseLocalCircumstances> FindCitiesOnCentralLine(PolynomialBesselianElements be, ICollection <CrdsGeographical> centralLine, CancellationToken?cancelToken = null, IProgress <double> progress = null)
{
var cities = new List <CrdsGeographical>();
for (int i = 0; i < centralLine.Count - 1; i++)
{
// Report progess
progress?.Report((double)(i + 1) / centralLine.Count * 100);
// Exit loop if cancel requested
if (cancelToken?.IsCancellationRequested == true)
{
return(new SolarEclipseLocalCircumstances[0]);
}
// 2 successive points create a central line segment
var g0 = centralLine.ElementAt(i);
var g1 = centralLine.ElementAt(i + 1);
// Segment length, distance between 2 points on central line, in kilometers
var length = g0.DistanceTo(g1);
// Local circumstances at point "g0"
var local = SolarEclipses.LocalCircumstances(be, g0);
// Lunar umbra radius, in kilometers
float r = (float)(local.PathWidth / 2);
float r0 = r;
if (r < 10)
{
r = 10;
}
if (r > 0)
{
// Count of parts the segment should be splitted
int parts = (int)Math.Round(length / r);
// If the segment should be splitted
if (parts > 1)
{
// Find intermediate points and add closest cities
for (int j = 0; j < parts; j++)
{
// Exit loop if cancel requested
if (cancelToken?.IsCancellationRequested == true)
{
return(new SolarEclipseLocalCircumstances[0]);
}
var g = Angle.Intermediate(g0, g1, (float)j / parts);
var locations = locationsManager.Search(g, r);
cities.AddRange(locations.Where(loc => loc.DistanceTo(g) <= r0));
}
}
// The segment should not be splitted, add closest cities to the first point
else
{
var locations = locationsManager.Search(g0, r);
cities.AddRange(locations.Where(loc => loc.DistanceTo(g0) <= r0));
}
}
}
return(FindLocalCircumstancesForCities(be, cities, cancelToken, progress));
}
/// <inheritdoc/>
public PolynomialBesselianElements GetBesselianElements(double jdMaximum)
{
return(SolarEclipses.BesselianElements(jdMaximum, GetSunMoonPositions(jdMaximum, 12)));
}
