public SolarTime(DateTime today, Coordinates coordinates)
{
DateTime calendar = today.ToUniversalTime();
DateTime tomorrow = calendar.AddDays(1);
DateTime yesterday = calendar.AddDays(-1);
this.prevSolar = new SolarCoordinates(CalendricalHelper.JulianDay(yesterday));
this.solar = new SolarCoordinates(CalendricalHelper.JulianDay(today));
this.nextSolar = new SolarCoordinates(CalendricalHelper.JulianDay(tomorrow));
this.approximateTransit = Astronomical.ApproximateTransit(coordinates.Longitude,
solar.ApparentSiderealTime, solar.RightAscension);
double solarAltitude = -50.0 / 60.0;
this.observer = coordinates;
this.Transit = Astronomical.CorrectedTransit(this.approximateTransit, coordinates.Longitude,
solar.ApparentSiderealTime, solar.RightAscension, prevSolar.RightAscension,
nextSolar.RightAscension);
this.Sunrise = Astronomical.CorrectedHourAngle(this.approximateTransit, solarAltitude,
coordinates, false, solar.ApparentSiderealTime, solar.RightAscension,
prevSolar.RightAscension, nextSolar.RightAscension, solar.Declination,
prevSolar.Declination, nextSolar.Declination);
this.Sunset = Astronomical.CorrectedHourAngle(this.approximateTransit, solarAltitude,
coordinates, true, solar.ApparentSiderealTime, solar.RightAscension,
prevSolar.RightAscension, nextSolar.RightAscension, solar.Declination,
prevSolar.Declination, nextSolar.Declination);
}
public double HourAngle(double angle, bool afterTransit)
{
return(Astronomical.CorrectedHourAngle(this.approximateTransit, angle, this.observer,
afterTransit, this.solar.ApparentSiderealTime, this.solar.RightAscension,
this.prevSolar.RightAscension, this.nextSolar.RightAscension, this.solar.Declination,
this.prevSolar.Declination, this.nextSolar.Declination));
}
public SolarCoordinates(double julianDay)
{
double T = CalendricalHelper.JulianCentury(julianDay);
double L0 = Astronomical.MeanSolarLongitude(/* julianCentury */ T);
double Lp = Astronomical.MeanLunarLongitude(/* julianCentury */ T);
double Ω = Astronomical.AscendingLunarNodeLongitude(/* julianCentury */ T);
double λ = MathHelper.ToRadians(
Astronomical.ApparentSolarLongitude(/* julianCentury*/ T, /* meanLongitude */ L0));
double θ0 = Astronomical.MeanSiderealTime(/* julianCentury */ T);
double ΔΨ = Astronomical.NutationInLongitude(/* julianCentury */ T, /* solarLongitude */ L0,
/* lunarLongitude */ Lp, /* ascendingNode */ Ω);
double Δε = Astronomical.NutationInObliquity(/* julianCentury */ T, /* solarLongitude */ L0,
/* lunarLongitude */ Lp, /* ascendingNode */ Ω);
double ε0 = Astronomical.MeanObliquityOfTheEcliptic(/* julianCentury */ T);
double εapp = MathHelper.ToRadians(Astronomical.ApparentObliquityOfTheEcliptic(
/* julianCentury */ T, /* meanObliquityOfTheEcliptic */ ε0));
/* Equation from Astronomical Algorithms page 165 */
this.Declination = MathHelper.ToDegrees(Math.Asin(Math.Sin(εapp) * Math.Sin(λ)));
/* Equation from Astronomical Algorithms page 165 */
this.RightAscension = DoubleUtil.UnwindAngle(
MathHelper.ToDegrees(Math.Atan2(Math.Cos(εapp) * Math.Sin(λ), Math.Cos(λ))));
/* Equation from Astronomical Algorithms page 88 */
this.ApparentSiderealTime = θ0 + (((ΔΨ * 3600) * Math.Cos(MathHelper.ToRadians(ε0 + Δε))) / 3600);
}
