// FajrAngle and IshaAngle are based on the 5 different methods of calculating prayer (ISNA, Muslim World League, etc.)
public static string find_sun_and_twi_events_for_date(double mjd, double timezone, double longitude, double latitude, double imsaakAngle, double FajrAngle, double IshaAngle, AstroValues astroValues)
{
double slatitude, mydate, ym, yz, utrise = 0, utset = 0;
bool above, rise, sett;
//
// this is my attempt to encapsulate most of the program in a function
// then this function can be generalised to find all the Sun events.
double yp, nz, hour, z1 = 0, z2 = 0, iobj, clatitude, rads;
rads = 0.0174532925;
double[] sinho = new double[6] {
Math.Sin(rads * -0.833), // sunset upper limb simple refraction
Math.Sin(rads * -4.0), // civil twi
Math.Sin(rads * -12.0), // nautical twi // Angle of Sun for Imsaak, Fajr and Isha
Math.Sin(rads * FajrAngle), // astro twi (-18.0)
Math.Sin(rads * IshaAngle), // astro twi (-18.0)
Math.Sin(rads * imsaakAngle) // usually -18
};
string always_up = " ****";
string always_down = " ....";
string outstring = "";
//
// Set up the array with the 4 values of sinho needed for the 4
// kinds of sun event
//
slatitude = Math.Sin(rads * latitude);
clatitude = Math.Cos(rads * latitude);
mydate = mjd - timezone / 24;
//
// main loop takes each value of sinho in turn and finds the rise/set
// events associated with that altitude of the Sun
//
for (int j = 0; j <= 5; j++)
{
rise = false;
sett = false;
above = false;
hour = 1.0;
ym = (double)sin_alt(2, mydate, hour - 1.0, longitude, clatitude, slatitude) - sinho[j];
if ((ym > 0.0))
{
above = true;
}
//
// the while loop finds the sin(alt) for sets of three consecutive
// hours, and then tests for a single zero crossing in the interval
// or for two zero crossings in an interval or for a grazing event
// The flags rise and sett are set accordingly
//
while ((hour < 25 & (sett == false || rise == false)))
{
yz = sin_alt(2, mydate, hour, longitude, clatitude, slatitude) - sinho[j];
yp = sin_alt(2, mydate, hour + 1.0, longitude, clatitude, slatitude) - sinho[j];
// finds the parabola throuh the three points (-1,ym), (0,yz), (1, yp)
// and returns the coordinates of the max/min (if any) xe, ye
// the values of x where the parabola crosses zero (roots of the quadratic)
// and the number of roots (0, 1 or 2) within the interval [-1, 1]
//
// well, this routine is producing sensible answers
//
// results passed as array [nz, z1, z2, xe, ye]
//
double dx;
nz = 0;
double a = 0.5 * (ym + yp) - yz;
double b = 0.5 * (yp - ym);
double c = yz;
double xe = -b / (2 * a);
double ye = (a * xe + b) * xe + c;
double dis = b * b - 4.0 * a * c;
if ((dis > 0))
{
dx = 0.5 * Math.Sqrt(dis) / Math.Abs(a);
z1 = xe - dx;
z2 = xe + dx;
if ((Math.Abs(z1) <= 1.0))
{
nz = nz + 1;
}
if ((Math.Abs(z2) <= 1.0))
{
nz = nz + 1;
}
if ((z1 < -1.0))
{
z1 = z2;
}
}
// case when one event is found in the interval
if ((nz == 1))
{
if ((ym < 0.0))
{
utrise = hour + z1;
rise = true;
}
else
{
utset = hour + z1;
sett = true;
}
} // end of nz = 1 case
// case where two events are found in this interval
// (rare but whole reason we are not using simple iteration)
if ((nz == 2))
{
if ((ye < 0.0))
{
utrise = hour + z2;
utset = hour + z1;
}
else
{
utrise = hour + z1;
utset = hour + z2;
}
} // end of nz = 2 case
// set up the next search interval
ym = yp;
hour = hour + 2.0;
}
// now search has completed, we compile the string to pass back
// to the main loop. The string depends on several combinations
// of the above flag (always above or always below) and the rise
// and sett flags
//
DateTime cur;
if ((rise == true || sett == true))
{
if ((rise == true))
{
cur = DateTime.Parse(hrsmin(utrise));
}
else
{
cur = DateTime.Parse("1/1/1900");
}
if (j == 0)
{
astroValues.sunset_begin = cur;
}
else if (j == 1)
{
astroValues.civil_begin = cur;
}
else if (j == 2)
{
astroValues.naut_begin = cur;
}
else if (j == 3)
{
astroValues.astro_begin = cur;
}
else if (j == 4)
{
}
else if (j == 5)
{
astroValues.imsaak_begin = cur;
}
// -------------------------------------
if ((sett == true))
{
cur = DateTime.Parse(hrsmin(utset));
}
else
{
cur = DateTime.Parse("1/1/1900");
}
if (j == 0)
{
astroValues.sunset_end = cur;
}
else if (j == 1)
{
astroValues.civil_end = cur;
}
else if (j == 2)
{
astroValues.naut_end = cur;
}
else if (j == 4)
{
astroValues.astro_end = cur;
}
}
else if ((above == true))
{
outstring = outstring + always_up + always_up;
}
else
{
outstring = outstring + always_down + always_down;
}
} // end of for loop - next condition
return(outstring);
}
public static PrayerTimes GetPrayerTimes(SchoolsofThought Madhab, PrayerCalculationMethod Calc_Method, DateTime doDate, double longitude, double latitude, double timezone, bool doDayLightSavings)
{
PrayerTimes prayerTimes = new PrayerTimes();
AstroValues astroValues = new AstroValues();
int myday = doDate.Day;
int mymonth = doDate.Month;
int myyear = doDate.Year;
double mj;
double diffMin;
DateTime curDate;
//
// main loop. All the work is done in the functions with the double names
// find_sun_and_twi_events_for_date() and find_moonrise_set()
//
mj = JulianDay(myday, mymonth, myyear, 0);
double imsaakAngle;
double fajrAngle;
double IshaAngle;
if (Calc_Method == PrayerCalculationMethod.Karachi)
{
imsaakAngle = -18; fajrAngle = -18.0; IshaAngle = -18.0;
}
else if (Calc_Method == PrayerCalculationMethod.ISNA)
{
imsaakAngle = -18; fajrAngle = -15.0; IshaAngle = -15.0;
}
else if (Calc_Method == PrayerCalculationMethod.MuslimWorldLeague)
{
imsaakAngle = -18; fajrAngle = -18.0; IshaAngle = -17.0;
}
else if (Calc_Method == PrayerCalculationMethod.Egypt)
{
imsaakAngle = -19.5; fajrAngle = -19.5; IshaAngle = -17.5;
}
else
{
imsaakAngle = -18; fajrAngle = -16.0; IshaAngle = -15.0;
}
// Start Loop here if you want to go through dates
astroCalcs.find_sun_and_twi_events_for_date(mj, timezone, longitude, latitude, imsaakAngle, fajrAngle, IshaAngle, astroValues);
diffMin = Math.Abs((astroValues.sunset_end - astroValues.sunset_begin).TotalMinutes);
curDate = new DateTime(myyear, mymonth, myday);
getAsr getAsr = new getAsr();
prayerTimes.Fajr = astroValues.astro_begin;
prayerTimes.SunRise = astroValues.sunset_begin;
prayerTimes.Dhuhr = astroValues.sunset_begin.AddMinutes(diffMin / 2); // DateAdd("n", diffMin / 2, (DateTime)sunset_begin);;
prayerTimes.Isha = astroValues.astro_end;
prayerTimes.SalatUlLayl = prayerTimes.Dhuhr.AddHours(12); // add 12 hours to zhuhr;
if (Madhab == SchoolsofThought.Hanafi)
{
prayerTimes.Imsaak = astroValues.imsaak_begin;
prayerTimes.Asr = getAsr.CalculateAsr(longitude, latitude, timezone, curDate, prayerTimes.Dhuhr, 2);
prayerTimes.Sunset = null;
prayerTimes.Maghrib = astroValues.sunset_end;
}
else if (Madhab == SchoolsofThought.Shaffii)
{
prayerTimes.Imsaak = astroValues.imsaak_begin;
prayerTimes.Asr = getAsr.CalculateAsr(longitude, latitude, timezone, curDate, prayerTimes.Dhuhr, 1);
prayerTimes.Sunset = null;
prayerTimes.Maghrib = astroValues.sunset_end;
}
else
{
prayerTimes.Imsaak = astroValues.imsaak_begin;
prayerTimes.Asr = getAsr.CalculateAsr(longitude, latitude, timezone, curDate, prayerTimes.Dhuhr, 1);
prayerTimes.Sunset = astroValues.sunset_end;
prayerTimes.Maghrib = astroValues.civil_end;
//prayerTimes.Midnight = DateAdd(DateInterval.Minute, (DateDiff(DateInterval.Minute, (DateTime)Today + " " + sunset_end, (DateTime)Today.AddDays(1) + " " + astro_begin) / 2), sunset_end);
prayerTimes.Midnight = astroValues.sunset_end.AddMinutes((astroValues.astro_begin.AddDays(1) - astroValues.sunset_end).TotalMinutes / 2);
}
getAsr = null /* TODO Change to default(_) if this is not a reference type */;
prayerTimes.Fajr = Convert.ToDateTime(prayerTimes.Fajr); // .AddMinutes(1)
prayerTimes.Dhuhr = Convert.ToDateTime(prayerTimes.Dhuhr).AddMinutes(1);
prayerTimes.Isha = Convert.ToDateTime(prayerTimes.Isha); // .AddMinutes(1)
switch (Calc_Method)
{
case PrayerCalculationMethod.LevaInstitute:
case PrayerCalculationMethod.ISNA:
{
prayerTimes.Imsaak = astroValues.imsaak_begin;
break;
}
case PrayerCalculationMethod.Karachi:
case PrayerCalculationMethod.MuslimWorldLeague:
case PrayerCalculationMethod.Saudi:
case PrayerCalculationMethod.Egypt:
{
prayerTimes.Imsaak = astroValues.astro_begin.AddMinutes(-10);
break;
}
}
// Apply Daylight Savings time if necessary
if (doDayLightSavings)
{
// DAY LIGHT SAVINGS TIME PART
bool do_DST; // Do Day Light savings or not
daylightSavings.GetDayLightSavings(myyear, out DateTime beginDST, out DateTime endDST);
do_DST = daylightSavings.isDST(beginDST, endDST, mymonth, myday);
if (do_DST == true)
{
prayerTimes.Imsaak = prayerTimes.Imsaak.AddHours(1);
prayerTimes.Fajr = prayerTimes.Fajr.AddHours(1);
prayerTimes.SunRise = prayerTimes.SunRise.AddHours(1);
prayerTimes.Dhuhr = prayerTimes.Dhuhr.AddHours(1);
prayerTimes.Asr = prayerTimes.Asr.AddHours(1);
if (prayerTimes.Sunset.HasValue)
{
prayerTimes.Sunset = prayerTimes.Sunset.Value.AddHours(1);
}
prayerTimes.Maghrib = prayerTimes.Maghrib.AddHours(1);
prayerTimes.Isha = prayerTimes.Isha.AddHours(1);
prayerTimes.Midnight = prayerTimes.Midnight.AddHours(1);
prayerTimes.SalatUlLayl = prayerTimes.SalatUlLayl.AddHours(1);
}
}
return(prayerTimes);
} // end of main program
