public Suntime Suntimes(Location location)
{
return SunTimes.Instance.CalculateSunRiseSetTimes(location, CurrentTime);
}
/// <summary>
/// Calculate sunrise and sunset times. Returns false if time zone and intitude are incompatible.
/// </summary>
/// <param name="lat">Latitude in decimal notation.</param>
/// <param name="lon">intitude in decimal notation.</param>
/// <param name="date">Date for which to calculate.</param>
/// <param name="riseTime">Sunrise time (output)</param>
/// <param name="setTime">Sunset time (output)</param>
/// <param name="isSunrise">Whether or not the sun rises at that day</param>
/// <param name="isSunset">Whether or not the sun sets at that day</param>
public Suntime CalculateSunRiseSetTimes(Location location, DateTime date)
{
lock (mLock) // lock for thread safety
{
Suntime suntime = new Suntime();
double zone = -(int) Math.Round(TimeZone.CurrentTimeZone.GetUtcOffset(date).Seconds/3600);
double jd = GetJulianDay(date) - 2451545; // Julian day relative to Jan 1.5, 2000
if ((Sign(zone) == Sign(location.Longitude)) && (zone != 0))
{
Debug.Print("WARNING: time zone and intitude are incompatible!");
suntime.Valid = false;
return suntime;
}
location.Longitude = location.Longitude / 360;
double tz = zone/24;
double ct = jd/36525 + 1; // centuries since 1900.0
double t0 = LocalSiderealTimeForTimeZone(location.Longitude, jd, tz); // local sidereal time
// get sun position at start of day
jd += tz;
CalculateSunPosition(jd, ct);
double ra0 = mSunPositionInSkyArr[0];
double dec0 = mSunPositionInSkyArr[1];
// get sun position at end of day
jd += 1;
CalculateSunPosition(jd, ct);
double ra1 = mSunPositionInSkyArr[0];
double dec1 = mSunPositionInSkyArr[1];
// make continuous
if (ra1 < ra0)
ra1 += 2*Math.PI;
// initialize
mIsSunrise = false;
mIsSunset = false;
mRightAscentionArr[0] = ra0;
mDecensionArr[0] = dec0;
// check each hour of this day
for (int k = 0; k < 24; k++)
{
mRightAscentionArr[2] = ra0 + (k + 1)*(ra1 - ra0)/24;
mDecensionArr[2] = dec0 + (k + 1)*(dec1 - dec0)/24;
mVHzArr[2] = TestHour(k, zone, t0, location.Latitude);
// advance to next hour
mRightAscentionArr[0] = mRightAscentionArr[2];
mDecensionArr[0] = mDecensionArr[2];
mVHzArr[0] = mVHzArr[2];
}
suntime.Sunrise = new DateTime(date.Year, date.Month, date.Day, mRiseTimeArr[0], mRiseTimeArr[1], 0);
suntime.Sunset = new DateTime(date.Year, date.Month, date.Day, mSetTimeArr[0], mSetTimeArr[1], 0);
suntime.IsSunSet = true;
suntime.IsSunRise = true;
// neither sunrise nor sunset
if ((!mIsSunrise) && (!mIsSunset))
{
if (mVHzArr[2] < 0)
suntime.IsSunRise = false; // Sun down all day
else
suntime.IsSunSet = false; // Sun up all day
}
// sunrise or sunset
else
{
if (!mIsSunrise)
// No sunrise this date
suntime.IsSunRise = false;
else if (!mIsSunset)
// No sunset this date
suntime.IsSunSet = false;
}
suntime.Valid = true;
return suntime;
}
}
