/// <summary>
/// Calculates sun times for a given date, latitude/longitude, and, optionally,
/// the observer height (in meters) relative to the horizon
/// </summary>
/// <param name="date">date to calculate for</param>
/// <param name="latitude">latitude in degrees</param>
/// <param name="longitude">longitude in degrees</param>
/// <param name="height">observer height relative to the horizon in metres (optional)</param>
/// <returns></returns>
public static SunTimes GetTimes(DateTime date, double latitude, double longitude, double height = 0)
{
var lw = Constants.Rad * -longitude;
var phi = Constants.Rad * latitude;
var dh = Sun.ObserverAngle(height);
var d = Calendar.ToDays(date);
var n = Sun.JulianCycle(d, lw);
var ds = Sun.ApproxTransit(0, lw, n);
var M = Sun.SolarMeanAnomaly(ds);
var L = Sun.EclipticLongitude(M);
var dec = Position.Declination(L, 0);
var Jnoon = Sun.SolarTransitJ(ds, M, L);
var result = new SunTimes
{
SolarNoon = Calendar.FromJulian(Jnoon),
Nadir = Calendar.FromJulian(Jnoon - 0.5)
};
for (int i = 0, len = Times.Count; i < len; i += 1)
{
var time = Times[i];
var h0 = (time.Angle + dh) * Constants.Rad;
var Jset = Sun.GetSetJ(h0, lw, phi, dec, n, M, L);
if (!double.IsNaN(Jset))
{
var Jrise = Jnoon - (Jset - Jnoon);
time.SetRiseProperty(result, Calendar.FromJulian(Jrise));
time.SetSetProperty(result, Calendar.FromJulian(Jset));
}
}
return(result);
}
