private static DateTime Get_Soltice_Equinox_From_JDE0(double JDE0, double offset)
{
//Get Event Ch 27.
double T = (JDE0 - 2451545.0) / 36525;
double W = (35999.373 * Math.PI / 180) * T - (2.47 * Math.PI / 180);
double ang = 1 + .0334 * Math.Cos(W) + .0007 * Math.Cos(2 * W);
double sum = MeeusTables.Equinox_Solstice_Sum_of_S(T);
double JDE = JDE0 + ((.00001) * sum / ang);
DateTime?d = JulianConversions.GetDate_FromJulian(JDE);
if (d.HasValue)
{
return(JulianConversions.GetDate_FromJulian(JDE).Value.AddHours(offset));
}
return(new DateTime()); //Julian limit exceeded, return empty DateTime
}
/// <summary>
/// Gets times for additional solar times
/// </summary>
private static void getTimes(DateTime date, double lng, double lat, Celestial c)
{
//Get Julian
double d = JulianConversions.GetJulian(date) - j2000 + .5; //LESS PRECISE JULIAN NEEDED
double lw = rad * -lng;
double phi = rad * lat;
double n = julianCycle(d, lw);
double ds = approxTransit(0, lw, n);
double M = solarMeanAnomaly(ds);
double L = eclipticLongitude(M);
double dec = declination(L, 0);
double Jnoon = solarTransitJ(ds, M, L);
double Jset;
double Jrise;
DateTime?solarNoon = JulianConversions.GetDate_FromJulian(Jnoon);
DateTime?nadir = JulianConversions.GetDate_FromJulian(Jnoon - 0.5);
c.AdditionalSolarTimes = new AdditionalSolarTimes();
//Dusk and Dawn
Jset = GetTime(-6 * rad, lw, phi, dec, n, M, L);
Jrise = Jnoon - (Jset - Jnoon);
c.AdditionalSolarTimes.CivilDawn = DayMatch(JulianConversions.GetDate_FromJulian(Jrise), date);
c.AdditionalSolarTimes.CivilDusk = DayMatch(JulianConversions.GetDate_FromJulian(Jset), date);
Jset = GetTime(-12 * rad, lw, phi, dec, n, M, L);
Jrise = Jnoon - (Jset - Jnoon);
c.AdditionalSolarTimes.NauticalDawn = DayMatch(JulianConversions.GetDate_FromJulian(Jrise), date);
c.AdditionalSolarTimes.NauticalDusk = DayMatch(JulianConversions.GetDate_FromJulian(Jset), date);
}
/// <summary>
/// Gets time of event based on specified degree below horizon
/// </summary>
/// <param name="lw">Observer Longitude in radians</param>
/// <param name="phi">Observer Latitude in radians</param>
/// <param name="h">Angle in Degrees</param>
/// <param name="date">Date of Event</param>
/// <returns>DateTime?[]{rise, set}</returns>
private static DateTime?[] Get_Event_Time(double lw, double phi, double h, DateTime date)
{
//Create arrays. Index 0 = Day -1, 1 = Day, 2 = Day + 1;
//These will be used to find exact day event occurs for comparison
DateTime?[] sets = new DateTime?[] { null, null, null, null, null };
DateTime?[] rises = new DateTime?[] { null, null, null, null, null };
//Iterate starting with day -1;
for (int x = 0; x < 5; x++)
{
double d = JulianConversions.GetJulian(date.AddDays(x - 2)) - j2000 + .5; //LESS PRECISE JULIAN NEEDED
double n = julianCycle(d, lw);
double ds = approxTransit(0, lw, n);
double M = solarMeanAnomaly(ds);
double L = eclipticLongitude(M);
double dec = declination(L, 0);
double Jnoon = solarTransitJ(ds, M, L);
double Jset;
double Jrise;
DateTime?solarNoon = JulianConversions.GetDate_FromJulian(Jnoon);
DateTime?nadir = JulianConversions.GetDate_FromJulian(Jnoon - 0.5);
//Rise Set
Jset = GetTime(h * rad, lw, phi, dec, n, M, L);
Jrise = Jnoon - (Jset - Jnoon);
DateTime?rise = JulianConversions.GetDate_FromJulian(Jrise);
DateTime?set = JulianConversions.GetDate_FromJulian(Jset);
rises[x] = rise;
sets[x] = set;
}
//Compare and send
DateTime?tRise = null;
for (int x = 0; x < 5; x++)
{
if (rises[x].HasValue)
{
if (rises[x].Value.Day == date.Day)
{
tRise = rises[x];
break;
}
}
}
DateTime?tSet = null;
for (int x = 0; x < 5; x++)
{
if (sets[x].HasValue)
{
if (sets[x].Value.Day == date.Day)
{
tSet = sets[x];
break;
}
}
}
return(new DateTime?[] { tRise, tSet });
}
/// <summary>
/// Gets time of event based on specified degree below specified altitude
/// </summary>
/// <param name="lw">Observer Longitude in radians</param>
/// <param name="phi">Observer Latitude in radians</param>
/// <param name="h">Angle in Degrees</param>
/// <param name="date">Date of Event</param>
/// <param name="offset">Offset hours</param>
/// <param name="calculateNoon">Should solar noon iterate and return value</param>
/// <returns>DateTime?[]{rise, set}</returns>
internal static DateTime?[] Get_Event_Time(double lw, double phi, double h, DateTime date, double offset, bool calculateNoon)
{
double julianOffset = offset * .04166667;
//Create arrays. Index 0 = Day -1, 1 = Day, 2 = Day + 1;
//These will be used to find exact day event occurs for comparison
DateTime?[] sets = new DateTime?[] { null, null, null, null, null };
DateTime?[] rises = new DateTime?[] { null, null, null, null, null };
DateTime?[] solarNoons = new DateTime?[] { null, null, null, null, null };
//Iterate starting with day -1;
for (int x = 0; x < 5; x++)
{
double d = JulianConversions.GetJulian(date.AddDays(x - 2)) - j2000 + .5; //LESS PRECISE JULIAN NEEDED
double n = julianCycle(d, lw);
//var celC = Get_Solar_Coordinates(date); //Change and Test locs!
double ds = approxTransit(0, lw, n);
//M = celC.MeanAnomaly.ToRadians();
double M = solarMeanAnomaly(ds);
double L = eclipticLongitude(M);
double dec = declination(L, 0);
double Jnoon = solarTransitJ(ds, M, L);
//Rise Set
double Jset = GetTime(h * rad, lw, phi, dec, n, M, L);
double Jrise = Jnoon - (Jset - Jnoon);
DateTime?rise = JulianConversions.GetDate_FromJulian(Jrise + julianOffset); //Adjusting julian for DT OFFSET MAY HELP WITH LOCAL TIME
DateTime?set = JulianConversions.GetDate_FromJulian(Jset + julianOffset); //Adjusting julian for DT OFFSET MAY HELP WITH LOCAL TIME
rises[x] = rise;
sets[x] = set;
if (calculateNoon)
{
solarNoons[x] = JulianConversions.GetDate_FromJulian(Jnoon + julianOffset);
}
}
//Compare and send
DateTime?tRise = Get_Event_Target_Date(rises, date);
DateTime?tSet = Get_Event_Target_Date(sets, date);
DateTime?tNoon = null;
if (calculateNoon)
{
tNoon = Get_Event_Target_Date(solarNoons, date);
}
return(new DateTime?[] { tRise, tSet, tNoon });
}
//v1.1.3 Formulas
//The following formulas are either additions
//or conversions of SunCalcs formulas into Meeus
/// <summary>
/// Grabs Perigee or Apogee of Moon based on specified time.
/// Results will return event just before, or just after specified DateTime
/// </summary>
/// <param name="d">DateTime</param>
/// <param name="md">Event Type</param>
/// <returns>PerigeeApogee</returns>
private static PerigeeApogee MoonPerigeeOrApogee(DateTime d, MoonDistanceType md)
{
//Perigee & Apogee Algorithms from Jean Meeus Astronomical Algorithms Ch. 50
//50.1
//JDE = 2451534.6698 + 27.55454989 * k
// -0.0006691 * Math.Pow(T,2)
// -0.000.01098 * Math.Pow(T,3)
// -0.0000000052 * Math.Pow(T,4)
//50.2
//K approx = (yv - 1999.97)*13.2555
//yv is the year + percentage of days that have occured in the year. 1998 Oct 1 is approx 1998.75
//k ending in .0 represent perigee and .5 apogee. Anything > .5 is an error.
//50.3
//T = k/1325.55
double yt = 365; //days in year
if (DateTime.IsLeapYear(d.Year))
{
yt = 366;
} //days in year if leap year
double f = d.DayOfYear / yt; //Get percentage of year that as passed
double yv = d.Year + f; //add percentage of year passed to year.
double k = (yv - 1999.97) * 13.2555; //find approximate k using formula 50.2
//Set k decimal based on apogee or perigee
if (md == MoonDistanceType.Apogee)
{
k = Math.Floor(k) + .5;
}
else
{
k = Math.Floor(k);
}
//Find T using formula 50.3
double T = k / 1325.55;
//Find JDE using formula 50.1
double JDE = 2451534.6698 + 27.55454989 * k -
0.0006691 * Math.Pow(T, 2) -
0.00001098 * Math.Pow(T, 3) -
0.0000000052 * Math.Pow(T, 4);
//Find Moon's mean elongation at time JDE.
double D = 171.9179 + 335.9106046 * k -
0.0100383 * Math.Pow(T, 2) -
0.00001156 * Math.Pow(T, 3) +
0.000000055 * Math.Pow(T, 4);
//Find Sun's mean anomaly at time JDE
double M = 347.3477 + 27.1577721 * k -
0.0008130 * Math.Pow(T, 2) -
0.0000010 * Math.Pow(T, 3);
//Find Moon's argument of latitude at Time JDE
double F = 316.6109 + 364.5287911 * k -
0.0125053 * Math.Pow(T, 2) -
0.0000148 * Math.Pow(T, 3);
//Normalize DMF to a 0-360 degree number
D %= 360;
if (D < 0)
{
D += 360;
}
M %= 360;
if (M < 0)
{
M += 360;
}
F %= 360;
if (F < 0)
{
F += 360;
}
//Convert DMF to radians
D = D * Math.PI / 180;
M = M * Math.PI / 180;
F = F * Math.PI / 180;
double termsA;
//Find Terms A from Table 50.A
if (md == MoonDistanceType.Apogee)
{
termsA = MeeusTables.ApogeeTermsA(D, M, F, T);
}
else
{
termsA = MeeusTables.PerigeeTermsA(D, M, F, T);
}
JDE += termsA;
double termsB;
if (md == MoonDistanceType.Apogee)
{
termsB = MeeusTables.ApogeeTermsB(D, M, F, T);
}
else
{
termsB = MeeusTables.PerigeeTermsB(D, M, F, T);
}
//Convert julian back to date
DateTime date = JulianConversions.GetDate_FromJulian(JDE).Value;
//Obtain distance
Distance dist = GetMoonDistance(date);
PerigeeApogee ap = new PerigeeApogee(date, termsB, dist);
return(ap);
}
