/// <summary>
/// Calculate the equation of time. (The difference between the real Sun time and the mean Sun time.)
/// </summary>
/// <param name="gwdateDay">Greenwich date (day part)</param>
/// <param name="gwdateMonth">Greenwich date (month part)</param>
/// <param name="gwdateYear">Greenwich date (year part)</param>
/// <returns>
/// <para>equation_of_time_min -- equation of time (minute part)</para>
/// <para>equation_of_time_sec -- equation of time (seconds part)</para>
/// </returns>
public (double equationOfTimeMin, double equationOfTimeSec) EquationOfTime(double gwdateDay, int gwdateMonth, int gwdateYear)
{
var sunLongitudeDeg = PAMacros.SunLong(12, 0, 0, 0, 0, gwdateDay, gwdateMonth, gwdateYear);
var sunRAHours = PAMacros.DecimalDegreesToDegreeHours(PAMacros.EcRA(sunLongitudeDeg, 0, 0, 0, 0, 0, gwdateDay, gwdateMonth, gwdateYear));
var equivalentUTHours = PAMacros.GreenwichSiderealTimeToUniversalTime(sunRAHours, 0, 0, gwdateDay, gwdateMonth, gwdateYear);
var equationOfTimeHours = equivalentUTHours - 12;
var equationOfTimeMin = PAMacros.DecimalHoursMinute(equationOfTimeHours);
var equationOfTimeSec = PAMacros.DecimalHoursSecond(equationOfTimeHours);
return(equationOfTimeMin, equationOfTimeSec);
}
/// <summary>
/// Calculate rising and setting times for an object.
/// </summary>
/// <returns>Tuple (riseSetStatus, utRiseHour, utRiseMin, utSetHour, utSetMin, azRise, azSet)</returns>
public (string riseSetStatus, double utRiseHour, double utRiseMin, double utSetHour, double utSetMin, double azRise, double azSet) RisingAndSetting(double raHours, double raMinutes, double raSeconds, double decDeg, double decMin, double decSec, double gwDateDay, int gwDateMonth, int gwDateYear, double geogLongDeg, double geogLatDeg, double vertShiftDeg)
{
var raHours1 = PAMacros.HMStoDH(raHours, raMinutes, raSeconds);
var decRad = PAMacros.DegreesMinutesSecondsToDecimalDegrees(decDeg, decMin, decSec).ToRadians();
var verticalDisplRadians = vertShiftDeg.ToRadians();
var geoLatRadians = geogLatDeg.ToRadians();
var cosH = -(verticalDisplRadians.Sine() + geoLatRadians.Sine() * decRad.Sine()) / (geoLatRadians.Cosine() * decRad.Cosine());
var hHours = PAMacros.DecimalDegreesToDegreeHours(PAMacros.Degrees(cosH.ACosine()));
var lstRiseHours = (raHours1 - hHours) - 24 * ((raHours1 - hHours) / 24).Floor();
var lstSetHours = (raHours1 + hHours) - 24 * ((raHours1 + hHours) / 24).Floor();
var aDeg = PAMacros.Degrees((((decRad).Sine() + (verticalDisplRadians).Sine() * (geoLatRadians).Sine()) / ((verticalDisplRadians).Cosine() * (geoLatRadians).Cosine())).ACosine());
var azRiseDeg = aDeg - 360 * (aDeg / 360).Floor();
var azSetDeg = (360 - aDeg) - 360 * ((360 - aDeg) / 360).Floor();
var utRiseHours1 = PAMacros.GreenwichSiderealTimeToUniversalTime(PAMacros.LocalSiderealTimeToGreenwichSiderealTime(lstRiseHours, 0, 0, geogLongDeg), 0, 0, gwDateDay, gwDateMonth, gwDateYear);
var utSetHours1 = PAMacros.GreenwichSiderealTimeToUniversalTime(PAMacros.LocalSiderealTimeToGreenwichSiderealTime(lstSetHours, 0, 0, geogLongDeg), 0, 0, gwDateDay, gwDateMonth, gwDateYear);
var utRiseAdjustedHours = utRiseHours1 + 0.008333;
var utSetAdjustedHours = utSetHours1 + 0.008333;
var riseSetStatus = "OK";
if (cosH > 1)
{
riseSetStatus = "never rises";
}
if (cosH < -1)
{
riseSetStatus = "circumpolar";
}
var utRiseHour = (riseSetStatus == "OK") ? PAMacros.DecimalHoursHour(utRiseAdjustedHours) : 0;
var utRiseMin = (riseSetStatus == "OK") ? PAMacros.DecimalHoursMinute(utRiseAdjustedHours) : 0;
var utSetHour = (riseSetStatus == "OK") ? PAMacros.DecimalHoursHour(utSetAdjustedHours) : 0;
var utSetMin = (riseSetStatus == "OK") ? PAMacros.DecimalHoursMinute(utSetAdjustedHours) : 0;
var azRise = (riseSetStatus == "OK") ? Math.Round(azRiseDeg, 2) : 0;
var azSet = (riseSetStatus == "OK") ? Math.Round(azSetDeg, 2) : 0;
return(riseSetStatus, utRiseHour, utRiseMin, utSetHour, utSetMin, azRise, azSet);
}
