//DateTime t must be in UTC
public static double GetSolarAltitudeInDegrees(double LatitudeInDegrees, double LongitudeInDegress, DateTime t)
{
double lonrad = LongitudeInDegress / 360 * 2 * Math.PI;
double latrad = LatitudeInDegrees / 360 * 2 * Math.PI;
int julian_date;
SolarCalculator.make_julian_day(t.Day, t.Month, t.Year, out julian_date);
double day_angle;//annual day angle
SolarCalculator.Day_Angle(julian_date, out day_angle);
double LAT; // sun local time
SolarCalculator.UT_to_LAT(t.TimeOfDay.TotalHours, day_angle, lonrad, out LAT);
double delta;//sun declination
SolarCalculator.declination_sun(t.Year, julian_date, lonrad, out delta);
double omega;//solar hour angle
SolarCalculator.solar_hour_angle(LAT, out omega);
double gamma, theta;//altitude angle and zenithal angle (complementary)
SolarCalculator.elevation_zenith_sun(latrad, delta, omega, out gamma, out theta);
return(gamma * 360 / 2 / Math.PI);
}