add files

1 files changed, 156 insertions, 0 deletions

diff --git a/src/sun.c b/src/sun.c
new file mode 100644
index 0000000..f08dfd8
--- /dev/null
+++ b/src/sun.c
@@ -0,0 +1,156 @@
+#include <math.h>
+#include <glib.h>
+#define PI 3.1415926
+#define ZENITH -.83
+
+float calculateSunrise(int year,int month,int day,float lat, float lng,int localOffset) {
+    /*
+    localOffset will be <0 for western hemisphere and >0 for eastern hemisphere
+    daylightSavings should be 1 if it is in effect during the summer otherwise it should be 0
+    */
+    //1. first calculate the day of the year
+    float N1 = floor(275 * month / 9);
+    float N2 = floor((month + 9) / 12);
+    float N3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3));
+    float N = N1 - (N2 * N3) + day - 30;
+
+    //2. convert the longitude to hour value and calculate an approximate time
+    float lngHour = lng / 15.0;
+    float t = N + ((6 - lngHour) / 24);
+
+    //3. calculate the Sun's mean anomaly
+    float M = (0.9856 * t) - 3.289;
+
+    //4. calculate the Sun's true longitude
+    float L = fmod(M + (1.916 * sin((PI/180)*M)) + (0.020 * sin(2 *(PI/180) * M)) + 282.634,360.0);
+
+    if ( L < 0 )
+      L = L+360;
+    else if ( L > 360)
+      L = L-360;
+
+    //5a. calculate the Sun's right ascension
+    float RA = fmod(180/PI*atan(0.91764 * tan((PI/180)*L)),360.0);
+
+    if ( RA < 0 )
+      RA = RA+360;
+    else if ( RA > 360)
+      RA = RA-360;
+
+    //5b. right ascension value needs to be in the same quadrant as L
+    float Lquadrant  = floor( L/90) * 90;
+    float RAquadrant = floor(RA/90) * 90;
+    RA = RA + (Lquadrant - RAquadrant);
+
+    //5c. right ascension value needs to be converted into hours
+    RA = RA / 15;
+
+    //6. calculate the Sun's declination
+    float sinDec = 0.39782 * sin((PI/180)*L);
+    float cosDec = cos(asin(sinDec));
+
+    //7a. calculate the Sun's local hour angle
+    float cosH = (sin((PI/180)*ZENITH) - (sinDec * sin((PI/180)*lat))) / (cosDec * cos((PI/180)*lat));
+
+    if (cosH >  1)
+      g_print("Never rising\n");
+    else if (cosH < -1)
+      g_print("Never setting\n");
+
+    //7b. finish calculating H and convert into hours
+    float H = 360 - (180/PI)*acos(cosH);   //   if if rising time is desired:
+
+    H = H / 15;
+
+    //8. calculate local mean time of rising/setting
+    float T = H + RA - (0.06571 * t) - 6.622;
+
+    //9. adjust back to UTC
+    float UT = fmod(T - lngHour,24.0);
+
+    if ( UT < 0 )
+      UT = UT+24;
+    else if (UT > 24)
+      UT = UT-24;
+
+    //10. convert UT value to local time zone of latitude/longitude
+    return UT + localOffset;
+
+    }
+
+float calculateSunset(int year,int month,int day,float lat, float lng,int localOffset) {
+   /*
+    localOffset will be <0 for western hemisphere and >0 for eastern hemisphere
+    daylightSavings should be 1 if it is in effect during the summer otherwise it should be 0
+    */
+    //1. first calculate the day of the year
+    float N1 = floor(275 * month / 9);
+    float N2 = floor((month + 9) / 12);
+    float N3 = (1 + floor((year - 4 * floor(year / 4) + 2) / 3));
+    float N = N1 - (N2 * N3) + day - 30;
+
+    //2. convert the longitude to hour value and calculate an approximate time
+    float lngHour = lng / 15.0;
+
+    float t = N + ((18 - lngHour) / 24);   //if setting time is desired:
+
+    //3. calculate the Sun's mean anomaly
+    float M = (0.9856 * t) - 3.289;
+
+    //4. calculate the Sun's true longitude
+    float L = fmod(M + (1.916 * sin((PI/180)*M)) + (0.020 * sin(2 *(PI/180) * M)) + 282.634,360.0);
+
+    if ( L < 0 )
+      L = L+360;
+    else if ( L > 360)
+      L = L-360;
+
+    //5a. calculate the Sun's right ascension
+    float RA = fmod(180/PI*atan(0.91764 * tan((PI/180)*L)),360.0);
+
+    if ( RA < 0 )
+      RA = RA+360;
+    else if ( RA > 360)
+      RA = RA-360;
+
+    //5b. right ascension value needs to be in the same quadrant as L
+    float Lquadrant  = floor( L/90) * 90;
+    float RAquadrant = floor(RA/90) * 90;
+    RA = RA + (Lquadrant - RAquadrant);
+
+    //5c. right ascension value needs to be converted into hours
+    RA = RA / 15;
+
+    //6. calculate the Sun's declination
+    float sinDec = 0.39782 * sin((PI/180)*L);
+    float cosDec = cos(asin(sinDec));
+
+    //7a. calculate the Sun's local hour angle
+    float cosH = (sin((PI/180)*ZENITH) - (sinDec * sin((PI/180)*lat))) / (cosDec * cos((PI/180)*lat));
+
+    if (cosH >  1)
+      g_print("Never rising\n");
+    else if (cosH < -1)
+      g_print("Never setting\n");
+
+
+    //7b. finish calculating H and convert into hours
+
+    float H = (180/PI)*acos(cosH); //   if setting time is desired:
+    H = H / 15;
+
+    //8. calculate local mean time of rising/setting
+    float T = H + RA - (0.06571 * t) - 6.622;
+
+    //9. adjust back to UTC
+    float UT = fmod(T - lngHour,24.0);
+
+    if ( UT < 0 )
+      UT = UT+24;
+    else if (UT > 24)
+      UT = UT-24;
+
+    //10. convert UT value to local time zone of latitude/longitude
+    return UT + localOffset;
+
+}