private double GetCosineSunLocalHour(double sunTrueLong, Zenith zenith)
{
double sinSunDeclination = GetSinOfSunDeclination(sunTrueLong);
double cosineSunDeclination = GetCosineOfSunDeclination(sinSunDeclination);
double zenithInRads = Utility.ConvertDegreesToRadians(zenith.degrees);
double cosineZenith = Math.Cos(zenithInRads);
double sinLatitude = Math.Sin(Utility.ConvertDegreesToRadians(this.location.latitude));
double cosLatitude = Math.Cos(Utility.ConvertDegreesToRadians(this.location.latitude));
double sinDeclinationTimesSinLat = sinSunDeclination * sinLatitude;
double dividend = cosineZenith - sinDeclinationTimesSinLat;
double divisor = cosineSunDeclination * cosLatitude;
return(Utility.SetScale(dividend / divisor));
}
private double ComputerSolarEventTime(Zenith solarZenith, DateTime date, bool isSunrise)
{
date = TimeZoneInfo.ConvertTime(date, this.timeZone);
double longitudeHour = GetLongitudeHour(date, isSunrise);
double meanAnomaly = GetMeanAnomaly(longitudeHour);
double sunTrueLong = GetSunTrueLongitude(meanAnomaly);
double cosineSunLocalHour = GetCosineSunLocalHour(sunTrueLong, solarZenith);
if ((cosineSunLocalHour < -1d) || (cosineSunLocalHour > 1d))
{
throw new ArgumentOutOfRangeException("Sun Local Hour out of range");
}
double sunLocalHour = GetSunLocalHour(cosineSunLocalHour, isSunrise);
double localMeanTime = GetLocalMeanTime(sunTrueLong, longitudeHour, sunLocalHour);
double localTime = GetLocalTime(localMeanTime, date);
return(localTime);
}
/// <summary>
/// Computes the sunset time for the given zenith at the given date
/// </summary>
/// <param name="solarZenith"><see cref="Zenith"/> enum corresponding to the type of sunset to compute</param>
/// <param name="date"><see cref="DateTime"/> object representing the date to compute the sunset for</param>
/// <returns>The sunset time as a <see cref="DateTime?"/></returns>
public DateTime?ComputeSunsetCalendar(Zenith solarZenith, DateTime date)
{
return(GetLocalTimeAsDateTime(ComputerSolarEventTime(solarZenith, date, false), date));
}
/// <summary>
/// Computes the sunset time for the given zenith at the given date
/// </summary>
/// <param name="solarZenith"><see cref="Zenith"/> enum corresponding to the type of sunset to compute</param>
/// <param name="date"><see cref="DateTime"/> object representing the date to compute the sunset for</param>
/// <returns>The sunset time, in HH:MM format (24-hour clock), 00:00 if the sun does not set on the given date</returns>
public string ComputeSunsetTime(Zenith solarZenith, DateTime date)
{
return(GetLocalTimeAsString(ComputerSolarEventTime(solarZenith, date, false)));
}