int main(void){
double y,m,day,h,latit,longit;
float inlat,inlon,intz;
double tzone,d,lambda;
double obliq,alpha,delta,LL,equation,ha,hb,twx;
double twam,altmax,noont,settm,riset,twpm;
time_t sekunnit;
struct tm *p;
degs = 180.0/pi;
rads = pi/180.0;
// get the date and time from the user
// read system date and extract the year
/** First get time **/
time(&sekunnit);
/** Next get localtime **/
p=localtime(&sekunnit);
y = p->tm_year;
// this is Y2K compliant method
y+= 1900;
m = p->tm_mon + 1;
day = p->tm_mday;
h = 12;
printf("year %4d month %2d\n",(int)y,(int)m);
printf("Input latitude, longitude and timezone\n");
scanf("%20f", &inlat);
scanf("%20f", &inlon);
scanf("%20f", &intz);
latit = (double)inlat; longit = (double)inlon;
tzone = (double)intz;
// testing
// m=6; day=10;
d = FNday(y, m, day, h);
// Use FNsun to find the ecliptic longitude of the
// Sun
lambda = FNsun(d);
// Obliquity of the ecliptic
obliq = 23.439 * rads - .0000004 * rads * d;
// Find the RA and DEC of the Sun
alpha = atan2(cos(obliq) * sin(lambda), cos(lambda));
delta = asin(sin(obliq) * sin(lambda));
// Find the Equation of Time
// in minutes
// Correction suggested by David Smith
LL = L - alpha;
if (L < pi) LL += 2.0*pi;
equation = 1440.0 * (1.0 - LL / pi/2.0);
ha = f0(latit,delta);
hb = f1(latit,delta);
twx = hb - ha; // length of twilight in radians
twx = 12.0*twx/pi; // length of twilight in hours
printf("ha= %.2f hb= %.2f \n",ha,hb);
// Conversion of angle to hours and minutes //
daylen = degs*ha/7.5;
if (daylen<0.0001) {daylen = 0.0;}
// arctic winter //
riset = 12.0 - 12.0 * ha/pi + tzone - longit/15.0 + equation/60.0;
settm = 12.0 + 12.0 * ha/pi + tzone - longit/15.0 + equation/60.0;
noont = riset + 12.0 * ha/pi;
altmax = 90.0 + delta * degs - latit;
// Correction for S HS suggested by David Smith
// to express altitude as degrees from the N horizon
if (latit < delta * degs) altmax = 180.0 - altmax;
twam = riset - twx; // morning twilight begin
twpm = settm + twx; // evening twilight end
if (riset > 24.0) riset-= 24.0;
if (settm > 24.0) settm-= 24.0;
puts("\n Sunrise and set");
puts("===============");
printf(" year : %d \n",(int)y);
printf(" month : %d \n",(int)m);
printf(" day : %d \n\n",(int)day);
printf("Days since Y2K : %d \n",(int)d);
printf("Latitude : %3.1f, longitude: %3.1f, timezone: %3.1f \n",(float)latit,(float)longit,(float)tzone);
printf("Declination : %.2f \n",delta * degs);
printf("Daylength : "); showhrmn(daylen); puts(" hours \n");
printf("Civil twilight: ");
showhrmn(twam); puts("");
printf("Sunrise : ");
showhrmn(riset); puts("");
printf("Sun altitude ");
// Amendment by D. Smith
printf(" %.2f degr",altmax);
printf(" %s",latit>=0.0 ? "South" : "North");
printf(" at noontime "); showhrmn(noont); puts("");
printf("Sunset : ");
showhrmn(settm); puts("");
printf("Civil twilight: ");
showhrmn(twpm); puts("\n");
return 0;
}
/**
* Calculates all sun-related important times
* depending on time of year and location
* @param location Location to be used in calculation
* @param GPS_INFO GPS_INFO for current date
* @param CALCULATED_INFO CALCULATED_INFO (not yet used)
* @param tzone Timezone
* @return Always 0
*/
int SunEphemeris::CalcSunTimes(const GEOPOINT &location,
const NMEA_INFO &GPS_INFO,
const DERIVED_INFO &CALCULATED_INFO,
const double tzone)
{
// float intz;
double d,lambda;
double obliq,alpha,delta,LL,equation,ha,hb,twx;
int y, m, day, h;
// testing
// JG Removed simulator conditional code, since GPS_INFO now set up
// from system time.
m = GPS_INFO.Month;
y = GPS_INFO.Year;
day = GPS_INFO.Day;
h = ((int)GPS_INFO.Time)/3600;
h = (h % 24);
d = FNday(y, m, day, (float) h);
// Use FNsun to find the ecliptic longitude of the Sun
lambda = FNsun(d);
// Obliquity of the ecliptic
obliq = 23.439 * DEG_TO_RAD - .0000004 * DEG_TO_RAD * d;
// Find the RA and DEC of the Sun
alpha = atan2(cos(obliq) * sin(lambda), cos(lambda));
delta = asin(sin(obliq) * sin(lambda));
// Find the Equation of Time in minutes
// Correction suggested by David Smith
LL = L - alpha;
if (L < PI) LL += 2.0*PI;
equation = 1440.0 * (1.0 - LL / PI/2.0);
ha = f0(location.Latitude,delta);
hb = f1(location.Latitude,delta);
twx = hb - ha; // length of twilight in radians
twx = 12.0*twx/PI; // length of twilight in hours
// printf("ha= %.2f hb= %.2f \n",ha,hb);
// Conversion of angle to hours and minutes //
daylen = RAD_TO_DEG*ha/7.5;
if (daylen<0.0001) {
daylen = 0.0;
}
// arctic winter //
riset = 12.0 - 12.0 * ha/PI + tzone - location.Longitude/15.0 + equation/60.0;
settm = 12.0 + 12.0 * ha/PI + tzone - location.Longitude/15.0 + equation/60.0;
noont = riset + 12.0 * ha/PI;
altmax = 90.0 + delta * RAD_TO_DEG - location.Latitude;
// Correction for S HS suggested by David Smith
// to express altitude as degrees from the N horizon
if (location.Latitude < delta * RAD_TO_DEG) {
altmax = 180.0 - altmax;
}
twam = riset - twx; // morning twilight begin
twpm = settm + twx; // evening twilight end
if (riset > 24.0) riset-= 24.0;
if (settm > 24.0) settm-= 24.0;
/*
puts("\n Sunrise and set");
puts("===============");
printf(" year : %d \n",(int)y);
printf(" month : %d \n",(int)m);
printf(" day : %d \n\n",(int)day);
printf("Days since Y2K : %d \n",(int)d);
printf("Latitude : %3.1f, longitude: %3.1f, timezone: %3.1f \n",(float)latit,(float)longit,(float)tzone);
printf("Declination : %.2f \n",delta * RAD_TO_DEG);
printf("Daylength : "); showhrmn(daylen); puts(" hours \n");
printf("Civil twilight: ");
showhrmn(twam); puts("");
printf("Sunrise : ");
showhrmn(riset); puts("");
printf("Sun altitude ");
// Amendment by D. Smith
printf(" %.2f degr",altmax);
printf(latit>=0.0 ? " South" : " North");
printf(" at noontime "); showhrmn(noont); puts("");
printf("Sunset : ");
showhrmn(settm); puts("");
printf("Civil twilight: ");
showhrmn(twpm); puts("\n");
*/
// QUESTION TB: why not just void?
return 0;
}
