/*********************************************************************/
/* */
/* m1 - previous moon position */
/* m2 - next moon position */
/* s1 - previous sun position */
/* s2 - next sun position */
/* */
/* Test for conjunction of the sun and moon */
/* m1,s1 is in one time moment */
/* m2,s2 is in second time moment */
/* */
/* this function tests whether conjunction occurs between */
/* these two moments */
/* */
/*********************************************************************/
public static bool IsConjunction(double m1, double s1, double s2, double m2)
{
if (m2 < m1)
{
m2 += 360.0;
}
if (s2 < s1)
{
s2 += 360.0;
}
if ((m1 <= s1) && (s1 < s2) && (s2 <= m2))
{
return(true);
}
m1 = GCMath.putIn180(m1);
m2 = GCMath.putIn180(m2);
s1 = GCMath.putIn180(s1);
s2 = GCMath.putIn180(s2);
if ((m1 <= s1) && (s1 < s2) && (s2 <= m2))
{
return(true);
}
return(false);
}
///////////////////////////////////////////////////////////////////////
// GET PREVIOUS CONJUNCTION OF THE SUN AND MOON
//
// THIS IS HELP FUNCTION FOR GetPrevConjunction(VCTIME test_date,
// VCTIME &found, bool this_day, EARTHDATA earth)
//
// looking for previous sun-moon conjunction
// it starts from input day from 12:00 AM (noon) UTC
// so output can be the same day
// if output is the same day, then conjunction occurs between 00:00 AM and noon of this day
//
// date - input / output
// earth - input
// return value - sun longitude in degs
//
// error is when return value is greater than 999.0 deg
public static double GetPrevConjunction(ref GregorianDateTime date, GCEarthData earth)
{
int bCont = 32;
double prevSun = 0.0, prevMoon = 0.0, prevDiff = 0.0;
double nowSun = 0.0, nowMoon = 0.0, nowDiff = 0.0;
// SUNDATA sun;
double jd, longitudeMoon;
GregorianDateTime d = new GregorianDateTime();
d.Set(date);
d.shour = 0.5;
d.TimezoneHours = 0.0;
jd = d.GetJulian();//GetJulianDay(d.year, d.month, d.day);
// set initial data for input day
// NOTE: for grenwich
//SunPosition(d, earth, sun);
longitudeMoon = GCCoreAstronomy.GetMoonLongitude(d, earth);
prevSun = GCSunData.GetSunLongitude(d);
prevMoon = longitudeMoon;
prevDiff = GCMath.putIn180(prevSun - prevMoon);
do
{
// shift to day before
d.PreviousDay();
jd -= 1.0;
// calculation
//SunPosition(d, earth, sun);
longitudeMoon = GCCoreAstronomy.GetMoonLongitude(d, earth);
nowSun = GCSunData.GetSunLongitude(d);
nowMoon = longitudeMoon;
nowDiff = GCMath.putIn180(nowSun - nowMoon);
// if difference of previous has another sign than now calculated
// then it is the case that moon was faster than sun and he
//printf(" prevsun=%f\nprevmoon=%f\nnowsun=%f\nnowmoon=%f\n", prevSun, prevMoon, nowSun, nowMoon);
if (IsConjunction(nowMoon, nowSun, prevSun, prevMoon))
{
// now it calculates actual time and zodiac of conjunction
double x;
if (prevDiff == nowDiff)
{
return(0);
}
x = Math.Abs(nowDiff) / Math.Abs(prevDiff - nowDiff);
if (x < 0.5)
{
d.shour = x + 0.5;
}
else
{
d.NextDay();
d.shour = x - 0.5;
}
date.Set(d);
double other = GCSunData.GetSunLongitude(d);
// double other2 = nowSun + (prevSun - nowSun)*x;
GCMath.putIn360(prevSun);
GCMath.putIn360(nowSun);
if (Math.Abs(prevSun - nowSun) > 10.0)
{
return(GCMath.putIn180(nowSun) + (GCMath.putIn180(prevSun) - GCMath.putIn180(nowSun)) * x);
}
else
{
return(nowSun + (prevSun - nowSun) * x);
}
// return other2;
}
prevSun = nowSun;
prevMoon = nowMoon;
prevDiff = nowDiff;
bCont--;
}while (bCont >= 0);
return(1000.0);
}
/*********************************************************************/
/* */
/* */
/* */
/* */
/* */
/*********************************************************************/
public static double GetNextConjunction(GregorianDateTime test_date, out GregorianDateTime found, bool this_conj, GCEarthData earth)
{
double phi = 12.0;
double l1, l2, longitudeSun, longitudeMoon;
if (this_conj)
{
test_date.shour += 0.2;
test_date.NormalizeValues();
}
double jday = test_date.GetJulianComplete();
double xj;
GregorianDateTime d = new GregorianDateTime();
d.Set(test_date);
GregorianDateTime xd = new GregorianDateTime();
double scan_step = 1.0;
int prev_tit = 0;
int new_tit = -1;
longitudeMoon = GCCoreAstronomy.GetMoonLongitude(d, earth);
longitudeSun = GCSunData.GetSunLongitude(d);
l1 = GCMath.putIn180(longitudeMoon - longitudeSun);
prev_tit = GCMath.IntFloor(l1 / phi);
int counter = 0;
while (counter < 20)
{
xj = jday;
xd.Set(d);
jday += scan_step;
d.shour += scan_step;
if (d.shour > 1.0)
{
d.shour -= 1.0;
d.NextDay();
}
longitudeMoon = GCCoreAstronomy.GetMoonLongitude(d, earth);
longitudeSun = GCSunData.GetSunLongitude(d);
l2 = GCMath.putIn180(longitudeMoon - longitudeSun);
new_tit = GCMath.IntFloor(l2 / phi);
if (prev_tit < 0 && new_tit >= 0)
{
jday = xj;
d.Set(xd);
scan_step *= 0.5;
counter++;
continue;
}
else
{
l1 = l2;
}
prev_tit = new_tit;
}
found = new GregorianDateTime();
found.Set(d);
return(longitudeSun);
}
// this is not used effectovely
// it is just try to have some alternative function for calculation sun position
// but it needs to be fixed, because
// it calculates correct ecliptical coordinates, but when transforming
// into horizontal coordinates (azimut, elevation) it will do something wrong
public static GCHorizontalCoords sunPosition(int year, int month, int day, int hour, int min, int sec,
double lat, double longi)
{
double twopi = GCMath.PI2;
double deg2rad = GCMath.PI2 / 180;
int[] month_days = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30 };
for (int y2 = 0; y2 < month; y2++)
{
day += month_days[y2];
}
if ((year % 4 == 0) && ((year % 400 == 0) || (year % 100 != 0)) && (day >= 60) && !(month == 2 & day == 60))
{
day++;
}
//# Get Julian date - 2400000
double hourd = hour + min / 60.0 + sec / 3600.0; // hour plus fraction
double delta = year - 1949;
double leap = Math.Floor(delta / 4); // former leapyears
double jd = 32916.5 + delta * 365 + leap + day + hourd / 24.0;
// The input to the Atronomer's almanach is the difference between
// the Julian date and JD 2451545.0 (noon, 1 January 2000)
double time = jd - 51545.0;
// Ecliptic coordinates
// Mean longitude
double mnlong = GCMath.putIn360(280.460 + .9856474 * time);
// Mean anomaly
double mnanom = GCMath.putIn360(357.528 + .9856003 * time);
//mnanom <- mnanom * deg2rad
// Ecliptic longitude and obliquity of ecliptic
double eclong = mnlong + 1.915 * GCMath.sinDeg(mnanom) + 0.020 * GCMath.sinDeg(2 * mnanom);
eclong = GCMath.putIn360(eclong);
double oblqec = 23.439 - 0.0000004 * time;
//-- eclong <- eclong * deg2rad
//-- oblqec <- oblqec * deg2rad
// Celestial coordinates
// Right ascension and declination
double num = GCMath.cosDeg(oblqec) * GCMath.sinDeg(eclong);
double den = GCMath.cosDeg(eclong);
double ra = GCMath.arcTan2Deg(num, den);
while (ra < 0)
{
ra += 180;
}
//-- ra[den < 0] <- ra[den < 0] + pi
if (den >= 0 && num < 0)
{
ra += 360;
}
double dec = GCMath.arcSinDeg(GCMath.sinDeg(oblqec) * GCMath.sinDeg(eclong));
// Local coordinates
// Greenwich mean sidereal time
double gmst = 6.697375 + .0657098242 * time + hourd;
gmst = GCMath.putIn24(gmst);
// Local mean sidereal time
double lmst = gmst + longi / 15.0;
lmst = GCMath.putIn24(lmst);
lmst = lmst * 15.0;
// Hour angle
double ha = lmst - ra;
ha = GCMath.putIn180(ha);
// Azimuth and elevation
double el = GCMath.arcSinDeg(GCMath.sinDeg(dec) * GCMath.sinDeg(lat) + GCMath.cosDeg(dec) * GCMath.cosDeg(lat) * GCMath.cosDeg(ha));
double az = GCMath.arcSinDeg(-GCMath.cosDeg(dec) * GCMath.sinDeg(ha) / GCMath.cosDeg(el));
//# -----------------------------------------------
//# New code
//# Solar zenith angle
double zenithAngle = GCMath.arccosDeg(GCMath.sinDeg(lat) * GCMath.sinDeg(dec) + GCMath.cosDeg(lat) * GCMath.cosDeg(dec) * GCMath.cosDeg(ha));
//# Solar azimuth
az = GCMath.arccosDeg(((GCMath.sinDeg(lat) * GCMath.cosDeg(zenithAngle)) - GCMath.sinDeg(dec)) / (GCMath.cosDeg(lat) * GCMath.sinDeg(zenithAngle)));
//# -----------------------------------------------
//# Azimuth and elevation
el = GCMath.arcSinDeg(GCMath.sinDeg(dec) * GCMath.sinDeg(lat) + GCMath.cosDeg(dec) * GCMath.cosDeg(lat) * GCMath.cosDeg(ha));
//# -----------------------------------------------
//# New code
if (ha > 0)
{
az += 180;
}
else
{
az = 540 - az;
}
az = GCMath.putIn360(az);
// For logic and names, see Spencer, J.W. 1989. Solar Energy. 42(4):353
//cosAzPos <- (0 <= sin(dec) - sin(el) * sin(lat))
//sinAzNeg <- (sin(az) < 0)
//az[cosAzPos & sinAzNeg] <- az[cosAzPos & sinAzNeg] + twopi
//az[!cosAzPos] <- pi - az[!cosAzPos]
/*
* if (0 < GCMath.sinDeg(dec) - GCMath.sinDeg(el) * GCMath.sinDeg(lat))
* {
* if(GCMath.sinDeg(az) < 0)
* {
* az = az + 360;
* }
* }
* else
* {
* az = 180 - az;
* }
*/
//el <- el / deg2rad
//az <- az / deg2rad
//lat <- lat / deg2rad
GCHorizontalCoords coords;
coords.azimut = az;
coords.elevation = el;
return(coords);
}