CSharp: SunTimeCalculator

 

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using System; using System.Collections.Generic; using System.Linq; using System.Text;   namespace GeovinDu.Ticket.Common {     /// <summary>     ///     /// </summary>     public static class DateTimeJavaScriptExt     {           /// <summary>         /// Based on a JavaScript library SunCalc for calculating sun/moon position and light phases.         ///https://github.com/mourner/suncalc         /// </summary>         /// <param name="dt"></param>         /// <returns></returns>         public static double ValueOf(this DateTime dt) // JavaScript Date.valueOf()         {             dt = dt.Kind == DateTimeKind.Local ? dt.ToUniversalTime() : dt;             return (dt - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;         }         /// <summary>         ///         /// </summary>         /// <param name="dt"></param>         /// <param name="ms"></param>         /// <returns></returns>         public static DateTime FromJScriptValue(this DateTime dt, double ms)         {             return new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(ms);         }     }     /// <summary>     /// 计算日出日落时间，月升月落时间     ///     /// </summary>     public class SunTimeCalculator     {             #region 辅助函数         /// <summary>         /// 历元2000.0，即以2000年第一天开端为计日起始（天文学以第一天为0日而非1日）。         /// 它与UT（就是世界时，格林尼治平均太阳时）1999年末重合。         /// </summary>         /// <param name="y"></param>         /// <param name="m"></param>         /// <param name="d"></param>         /// <returns></returns>         private static long Days_since_2000_Jan_0(int y, int m, int d)         {             return (367L * (y) - ((7 * ((y) + (((m) + 9) / 12))) / 4) + ((275 * (m)) / 9) + (d) - 730530L);         }         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Revolution(double x)         {             return (x - 360.0 * Math.Floor(x * Inv360));         }         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Rev180(double x)         {             return (x - 360.0 * Math.Floor(x * Inv360 + 0.5));         }         /// <summary>         ///         /// </summary>         /// <param name="d"></param>         /// <returns></returns>         private static double GMST0(double d)         {             double sidtim0;             sidtim0 = Revolution((180.0 + 356.0470 + 282.9404) +                 (0.9856002585 + 4.70935E-5) * d);             return sidtim0;         }           /// <summary>         ///         /// </summary>         private static double Inv360 = 1.0 / 360.0;         #endregion           #region 度与弧度转换系数，为球面三角计算作准备         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Sind(double x)         {             return Math.Sin(x * Degrad);         }         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Cosd(double x)         {             return Math.Cos(x * Degrad);         }         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Tand(double x)         {             return Math.Tan(x * Degrad);           }         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Atand(double x)         {             return Radge * Math.Atan(x);         }         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Asind(double x)         {             return Radge * Math.Asin(x);         }         /// <summary>         ///         /// </summary>         /// <param name="x"></param>         /// <returns></returns>         private static double Acosd(double x)         {             return Radge * Math.Acos(x);         }         /// <summary>         ///         /// </summary>         /// <param name="y"></param>         /// <param name="x"></param>         /// <returns></returns>         private static double Atan2d(double y, double x)         {             return Radge * Math.Atan2(y, x);           }         /// <summary>         ///         /// </summary>         private static double Radge = 180.0 / Math.PI;         /// <summary>         ///         /// </summary>         private static double Degrad = Math.PI / 180.0;           #endregion           #region 与日出日落时间相关计算         /// <summary>         ///         /// </summary>         /// <param name="year"></param>         /// <param name="month"></param>         /// <param name="day"></param>         /// <param name="lon"></param>         /// <param name="lat"></param>         /// <param name="altit"></param>         /// <param name="upper_limb"></param>         /// <returns></returns>         private static double DayLen(int year, int month, int day, double lon, double lat,             double altit, int upper_limb)         {             double d,  /* Days since 2000 Jan 0.0 (negative before) */                 obl_ecl,    /* Obliquity (inclination) of Earth's axis */                 //黄赤交角，在2000.0历元下国际规定为23度26分21.448秒，但有很小的时间演化。                   sr,         /* Solar distance, astronomical units */                 slon,       /* True solar longitude */                 sin_sdecl,  /* Sine of Sun's declination */                 //太阳赤纬的正弦值。                 cos_sdecl,  /* Cosine of Sun's declination */                 sradius,    /* Sun's apparent radius */                 t;          /* Diurnal arc */               /* Compute d of 12h local mean solar time */             d = Days_since_2000_Jan_0(year, month, day) + 0.5 - lon / 360.0;               /* Compute obliquity of ecliptic (inclination of Earth's axis) */             obl_ecl = 23.4393 - 3.563E-7 * d;             //这个黄赤交角时变公式来历复杂，很大程度是经验性的，不必追究。               /* Compute Sun's position */             slon = 0.0;             sr = 0.0;             Sunpos(d, ref slon, ref sr);               /* Compute sine and cosine of Sun's declination */             sin_sdecl = Sind(obl_ecl) * Sind(slon);             cos_sdecl = Math.Sqrt(1.0 - sin_sdecl * sin_sdecl);             //用球面三角学公式计算太阳赤纬。               /* Compute the Sun's apparent radius, degrees */             sradius = 0.2666 / sr;             //视半径，同前。               /* Do correction to upper limb, if necessary */             if (upper_limb != 0)                 altit -= sradius;               /* Compute the diurnal arc that the Sun traverses to reach */             /* the specified altitide altit: */             //根据设定的地平高度判据计算周日弧长。             double cost;             cost = (Sind(altit) - Sind(lat) * sin_sdecl) /                 (Cosd(lat) * cos_sdecl);             if (cost >= 1.0)                 t = 0.0;                      /* Sun always below altit */             //极夜。             else if (cost <= -1.0)                 t = 24.0;                     /* Sun always above altit */             //极昼。             else t = (2.0 / 15.0) * Acosd(cost); /* The diurnal arc, hours */             //周日弧换算成小时计。             return t;           }         /// <summary>         ///         /// </summary>         /// <param name="d"></param>         /// <param name="lon"></param>         /// <param name="r"></param>         private static void Sunpos(double d, ref double lon, ref double r)         {             double M,//太阳的平均近点角，从太阳观察到的地球（=从地球看到太阳的）距近日点（近地点）的角度。                 w, //近日点的平均黄道经度。                 e, //地球椭圆公转轨道离心率。                 E, //太阳的偏近点角。计算公式见下面。                   x, y,                 v;  //真近点角，太阳在任意时刻的真实近点角。                 M = Revolution(356.0470 + 0.9856002585 * d);//自变量的组成：2000.0时刻太阳黄经为356.0470度,此后每天约推进一度（360度/365天             w = 282.9404 + 4.70935E-5 * d;//近日点的平均黄经。               e = 0.016709 - 1.151E-9 * d;//地球公转椭圆轨道离心率的时间演化。以上公式和黄赤交角公式一样，不必深究。               E = M + e * Radge * Sind(M) * (1.0 + e * Cosd(M));             x = Cosd(E) - e;             y = Math.Sqrt(1.0 - e * e) * Sind(E);             r = Math.Sqrt(x * x + y * y);             v = Atan2d(y, x);             lon = v + w;             if (lon >= 360.0)                 lon -= 360.0;         }         /// <summary>         ///         /// </summary>         /// <param name="d"></param>         /// <param name="RA"></param>         /// <param name="dec"></param>         /// <param name="r"></param>         private static void Sun_RA_dec(double d, ref double RA, ref double dec, ref double r)         {             double lon, obl_ecl, x, y, z;             lon = 0.0;               Sunpos(d, ref lon, ref r);             //计算太阳的黄道坐标。               x = r * Cosd(lon);             y = r * Sind(lon);             //计算太阳的直角坐标。               obl_ecl = 23.4393 - 3.563E-7 * d;             //黄赤交角，同前。               z = y * Sind(obl_ecl);             y = y * Cosd(obl_ecl);             //把太阳的黄道坐标转换成赤道坐标（暂改用直角坐标）。               RA = Atan2d(y, x);             dec = Atan2d(z, Math.Sqrt(x * x + y * y));             //最后转成赤道坐标。显然太阳的位置是由黄道坐标方便地直接确定的，但必须转换到赤             //道坐标里才能结合地球的自转确定我们需要的白昼长度。           }         /// <summary>         /// 日出没时刻计算         /// </summary>         /// <param name="year">年</param>         /// <param name="month">月</param>         /// <param name="day">日</param>         /// <param name="lon">经度</param>         /// <param name="lat">纬度</param>         /// <param name="altit"></param>         /// <param name="upper_limb"></param>         /// <param name="trise">日出时刻</param>         /// <param name="tset">日没时刻</param>         /// <returns>太阳有出没现象，返回0 极昼，返回+1 极夜，返回-1</returns>         private static int SunRiset(int year, int month, int day, double lon, double lat,             double altit, int upper_limb, ref double trise, ref double tset)         {             double d,  /* Days since 2000 Jan 0.0 (negative before) */                 //以历元2000.0起算的日数。                   sr,         /* Solar distance, astronomical units */                 //太阳距离，以天文单位计算（约1.5亿公里）。                        sRA,        /* Sun's Right Ascension */                 //同前，太阳赤经。                   sdec,       /* Sun's declination */                 //太阳赤纬。                   sradius,    /* Sun's apparent radius */                 //太阳视半径，约16分（受日地距离、大气折射等诸多影响）                   t,          /* Diurnal arc */                 //周日弧，太阳一天在天上走过的弧长。                   tsouth,     /* Time when Sun is at south */                 sidtime;    /* Local sidereal time */             //当地恒星时，即地球的真实自转周期。比平均太阳日（日常时间）长3分56秒。                    int rc = 0; /* Return cde from function - usually 0 */               /* Compute d of 12h local mean solar time */             d = Days_since_2000_Jan_0(year, month, day) + 0.5 - lon / 360.0;             //计算观测地当日中午时刻对应2000.0起算的日数。               /* Compute local sideral time of this moment */             sidtime = Revolution(GMST0(d) + 180.0 + lon);             //计算同时刻的当地恒星时（以角度为单位）。以格林尼治为基准，用经度差校正。               /* Compute Sun's RA + Decl at this moment */             sRA = 0.0;             sdec = 0.0;             sr = 0.0;             Sun_RA_dec(d, ref sRA, ref sdec, ref sr);             //计算同时刻太阳赤经赤纬。               /* Compute time when Sun is at south - in hours UT */             tsouth = 12.0 - Rev180(sidtime - sRA) / 15.0;             //计算太阳日的正午时刻，以世界时（格林尼治平太阳时）的小时计。               /* Compute the Sun's apparent radius, degrees */             sradius = 0.2666 / sr;             //太阳视半径。0.2666是一天文单位处的太阳视半径（角度）。               /* Do correction to upper limb, if necessary */             if (upper_limb != 0)                 altit -= sradius;             //如果要用上边缘，就要扣除一个视半径。               /* Compute the diurnal arc that the Sun traverses to reach */             //计算周日弧。直接利用球面三角公式。如果碰到极昼极夜问题，同前处理。             /* the specified altitide altit: */               double cost;             cost = (Sind(altit) - Sind(lat) * Sind(sdec)) /                 (Cosd(lat) * Cosd(sdec));             if (cost >= 1.0)             {                 rc = -1;                 t = 0.0;             }             else             {                 if (cost <= -1.0)                 {                     rc = +1;                     t = 12.0;      /* Sun always above altit */                 }                 else                     t = Acosd(cost) / 15.0;   /* The diurnal arc, hours */             }                 /* Store rise and set times - in hours UT */             trise = tsouth - t;             tset = tsouth + t;               return rc;         }         #endregion           /// <summary>         /// 计算日出日没时间         /// </summary>         /// <param name="date"></param>         /// <param name="longitude">经度</param>         /// <param name="latitude">纬度</param>         /// <returns></returns>         public static SunTimeResult GetSunTime(DateTime date, double longitude, double latitude)         {             double start = 0;             double end = 0;             SunRiset(date.Year, date.Month, date.Day, longitude, latitude, -35.0 / 60.0, 1, ref start, ref end);             DateTime sunrise = ToLocalTime(date, start);             DateTime sunset = ToLocalTime(date, end);             return new SunTimeResult(sunrise, sunset);         }           #region moon 月亮计算             private const double dayMs = 86400000;         private const double J1970 = 2440588;         private const double J2000 = 2451545;         private const double PI = Math.PI;         private const double rad = Math.PI / 180.0;         private const double e = rad * 23.4397; // obliquity of the Earth             /// <summary>         ///         /// </summary>         public class SunTime         {             public double Angle { get; set; }             public string MorningName { get; set; }             public string EveningName { get; set; }         }         /// <summary>         ///         /// </summary>         public class SunTimeRiseSet : SunTime         {             public DateTime RiseTime { get; set; }             public DateTime SetTime { get; set; }         }           /// <summary>         /// sun times configuration (angle, morning name, evening name)         /// </summary>           public static List<SunTime> SunTimes = new List<SunTime>(new SunTime[]         {             new SunTime { Angle = -0.833, MorningName = "sunrise", EveningName = "sunset" },             new SunTime { Angle = -0.3, MorningName = "sunriseEnd", EveningName = "sunsetStart" },             new SunTime { Angle = -6, MorningName = "dawn", EveningName = "dusk" },             new SunTime { Angle = -12, MorningName = "nauticalDawn", EveningName = "nauticalDusk" },             new SunTime { Angle = -18, MorningName = "nightEnd", EveningName = "night" },             new SunTime { Angle = 6, MorningName = "goldenHourEnd", EveningName = "goldenHour" }         });           /// <summary>         /// adds a custom time to the times config         /// </summary>         /// <param name="sunTime"></param>           public static void AddTime(SunTime sunTime)         {             SunTimes.Add(sunTime);         }         /// <summary>         ///         /// </summary>         public class RaDec         {             public double ra = 0;             public double dec = 0;         }         /// <summary>         ///         /// </summary>         /// <param name="dt"></param>         /// <returns></returns>         public static double ToJulianDate(DateTime dt)         {             dt = dt.Kind == DateTimeKind.Local ? dt.ToUniversalTime() : dt;             return (dt - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds / dayMs - 0.5 + J1970;         }         /// <summary>         ///         /// </summary>         /// <param name="jd"></param>         /// <returns></returns>         public static DateTime FromJulianDate(double jd)         {             return double.IsNaN(jd)                 ? DateTime.MinValue                 : new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds((jd + 0.5 - J1970) * dayMs);         }         /// <summary>         ///         /// </summary>         /// <param name="dt"></param>         /// <returns></returns>         public static double JulianDays(DateTime dt)         {             dt = dt.Kind == DateTimeKind.Local ? dt.ToUniversalTime() : dt;             return ToJulianDate(dt) - J2000;         }         /// <summary>         ///         /// </summary>         /// <param name="l"></param>         /// <param name="b"></param>         /// <returns></returns>         public static double RightAscension(double l, double b)         {             return Math.Atan2(Math.Sin(l) * Math.Cos(e) - Math.Tan(b) * Math.Sin(e), Math.Cos(l));         }           public static double Declination(double l, double b)         {             return Math.Asin(Math.Sin(b) * Math.Cos(e) + Math.Cos(b) * Math.Sin(e) * Math.Sin(l));         }         /// <summary>         ///         /// </summary>         /// <param name="H"></param>         /// <param name="phi"></param>         /// <param name="dec"></param>         /// <returns></returns>         public static double Azimuth(double H, double phi, double dec)         {             return Math.Atan2(Math.Sin(H), Math.Cos(H) * Math.Sin(phi) - Math.Tan(dec) * Math.Cos(phi));         }         /// <summary>         ///         /// </summary>         /// <param name="H"></param>         /// <param name="phi"></param>         /// <param name="dec"></param>         /// <returns></returns>         public static double Altitude(double H, double phi, double dec)         {             return Math.Asin(Math.Sin(phi) * Math.Sin(dec) + Math.Cos(phi) * Math.Cos(dec) * Math.Cos(H));         }         /// <summary>         ///         /// </summary>         /// <param name="d"></param>         /// <param name="lw"></param>         /// <returns></returns>         public static double SiderealTime(double d, double lw)         {             return rad * (280.16 + 360.9856235 * d) - lw;         }         /// <summary>         ///         /// </summary>         /// <param name="h"></param>         /// <returns></returns>         public static double AstroRefraction(double h)         {             if (h < 0) // the following formula works for positive altitudes only.             {                 h = 0; // if h = -0.08901179 a div/0 would occur.             }               // formula 16.4 of "Astronomical Algorithms" 2nd edition by Jean Meeus (Willmann-Bell, Richmond) 1998.             // 1.02 / tan(h + 10.26 / (h + 5.10)) h in degrees, result in arc minutes -> converted to rad:             return 0.0002967 / Math.Tan(h + 0.00312536 / (h + 0.08901179));         }           /// <summary>         /// general sun calculations         /// </summary>         /// <param name="d"></param>         /// <returns></returns>           public static double SolarMeanAnomaly(double d)         {             return rad * (357.5291 + 0.98560028 * d);         }         /// <summary>         ///         /// </summary>         /// <param name="dt"></param>         /// <param name="h"></param>         /// <returns></returns>         public static DateTime HoursLater(DateTime dt, double h)         {             return new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(dt.ValueOf() + h * dayMs / 24); //ValueOf         }         /// <summary>         ///         /// </summary>         /// <param name="M"></param>         /// <returns></returns>         public static double EclipticLongitude(double M)         {             double C = rad * (1.9148 * Math.Sin(M) + 0.02 * Math.Sin(2 * M) +                               0.0003 * Math.Sin(3 * M)); // equation of center             double P = rad * 102.9372; // perihelion of the Earth             return M + C + P + PI;         }         /// <summary>         ///         /// </summary>         /// <param name="d"></param>         /// <returns></returns>         public static RaDec SunCoords(double d)         {             double M = SolarMeanAnomaly(d);             double L = EclipticLongitude(M);             return new RaDec { dec = Declination(L, 0), ra = RightAscension(L, 0) };         }         /// <summary>         ///         /// </summary>         public class MoonRaDecDist         {             public double ra = 0;             public double dec = 0;             public double dist = 0;         }         /// <summary>         ///         /// </summary>         /// <param name="d"></param>         /// <returns></returns>         public static MoonRaDecDist MoonCoords(double d) // geocentric ecliptic coordinates of the moon         {             double L = rad * (218.316 + 13.176396 * d); // ecliptic longitude             double M = rad * (134.963 + 13.064993 * d); // mean anomaly             double F = rad * (93.272 + 13.229350 * d); // mean distance               double l = L + rad * 6.289 * Math.Sin(M); // longitude             double b = rad * 5.128 * Math.Sin(F); // latitude             double dt = 385001 - 20905 * Math.Cos(M); // distance to the moon in km               return new MoonRaDecDist { ra = RightAscension(l, b), dec = Declination(l, b), dist = dt };         }         /// <summary>         ///         /// </summary>         public class MoonAzAltDistPa         {             public double azimuth = 0;             public double altitude = 0;             public double distance = 0;             public double parallacticAngle = 0;         }         /// <summary>         ///         /// </summary>         public class MoonFracPhaseAngle         {             public double fraction = 0;             public double phase = 0;             public double angle = 0;         }         /// <summary>         ///         /// </summary>         /// <param name="dt"></param>         /// <param name="lat"></param>         /// <param name="lng"></param>         /// <returns></returns>         public static MoonAzAltDistPa GetMoonPosition(DateTime dt, double lat, double lng)         {             double lw = rad * -lng;             double phi = rad * lat;             double d = JulianDays(dt);               MoonRaDecDist c = MoonCoords(d);             double H = SiderealTime(d, lw) - c.ra;             double h = Altitude(H, phi, c.dec);             // formula 14.1 of "Astronomical Algorithms" 2nd edition by Jean Meeus (Willmann-Bell, Richmond) 1998.             double pa = Math.Atan2(Math.Sin(H), Math.Tan(phi) * Math.Cos(c.dec) - Math.Sin(c.dec) * Math.Cos(H));               h += AstroRefraction(h); // altitude correction for refraction             return new MoonAzAltDistPa { azimuth = Azimuth(H, phi, c.dec), altitude = h, distance = c.dist, parallacticAngle = pa };         }         /// <summary>         ///         /// </summary>         /// <param name="dt"></param>         /// <returns></returns>         public static MoonFracPhaseAngle GetMoonIllumination(DateTime dt)         {             double d = JulianDays(dt);             RaDec s = SunCoords(d);             MoonRaDecDist m = MoonCoords(d);             double sdist = 149598000; // distance from Earth to Sun in km             double phi = Math.Acos(Math.Sin(s.dec) * Math.Sin(m.dec) +                                    Math.Cos(s.dec) * Math.Cos(m.dec) * Math.Cos(s.ra - m.ra));             double inc = Math.Atan2(sdist * Math.Sin(phi), m.dist - sdist * Math.Cos(phi));             double angle = Math.Atan2(Math.Cos(s.dec) * Math.Sin(s.ra - m.ra), Math.Sin(s.dec) * Math.Cos(m.dec) -                 Math.Cos(s.dec) * Math.Sin(m.dec) * Math.Cos(s.ra - m.ra));             return new MoonFracPhaseAngle             {                 fraction = (1 + Math.Cos(inc)) / 2,                 phase = 0.5 + 0.5 * inc * (angle < 0 ? -1 : 1) / PI,                 angle = angle             };         }           /// <summary>         /// DateTime.Max = always up, DateTime.Min = always down         /// </summary>         /// <param name="dt"></param>         /// <param name="lat">纬度</param>         /// <param name="lng">经度</param>         /// <param name="risem"></param>         /// <param name="setm"></param>         /// <param name="alwaysUp"></param>         /// <param name="alwaysDown"></param>         public static void MoonRiset(DateTime dt, double lat, double lng, out DateTime risem, out DateTime setm,             out bool? alwaysUp, out bool? alwaysDown)         {             dt = new DateTime(dt.Year, dt.Month, dt.Day, 0, 0, 0, DateTimeKind.Utc);             DateTime t = dt;               double hc = 0.133 * rad;             double h0 = GetMoonPosition(t, lat, lng).altitude - hc;             double h1, h2, rise = 0, set = 0, a, b, xe, ye = 0, d, x1, x2, dx;             int roots;               for (double i = 1.0; i <= 24.0; i += 2.0)             {                 h1 = GetMoonPosition(HoursLater(t, i), lat, lng).altitude - hc;                 h2 = GetMoonPosition(HoursLater(t, i + 1), lat, lng).altitude - hc;                   a = (h0 + h2) / 2 - h1;                 b = (h2 - h0) / 2;                 xe = -b / (2 * a);                 ye = (a * xe + b) * xe + h1;                 d = b * b - 4 * a * h1;                 roots = 0;                   if (d >= 0)                 {                     dx = Math.Sqrt(d) / (Math.Abs(a) * 2);                     x1 = xe - dx;                     x2 = xe + dx;                     if (Math.Abs(x1) <= 1)                     {                         roots++;                     }                       if (Math.Abs(x2) <= 1)                     {                         roots++;                     }                       if (x1 < -1)                     {                         x1 = x2;                     }                       if (roots == 1)                     {                         if (h0 < 0)                         {                             rise = i + x1;                         }                         else                         {                             set = i + x1;                         }                     }                     else if (roots == 2)                     {                         rise = i + (ye < 0 ? x2 : x1);                         set = i + (ye < 0 ? x1 : x2);                     }                       if (rise > 0 && set > 0)                     {                         break;                     }                       h0 = h2;                 }             }               risem = DateTime.MinValue;             setm = DateTime.MinValue;               if (rise > 0)             {                 risem = HoursLater(t, rise);             }               if (set > 0)             {                 setm = HoursLater(t, set);             }               alwaysUp = null;             alwaysDown = null;               if (rise < 0 && set < 0)             {                 if (ye > 0)                 {                     alwaysUp = true;                     alwaysDown = false;                     risem = DateTime.MaxValue;                     setm = DateTime.MaxValue;                 }                 else                 {                     alwaysDown = true;                     alwaysUp = false;                 }             }         }         /// <summary>         ///         /// </summary>         /// <param name="year"></param>         /// <param name="month"></param>         /// <param name="day"></param>         /// <param name="lat">纬度</param>         /// <param name="lng">经度</param>         /// <param name="risem"></param>         /// <param name="setm"></param>         /// <param name="alwaysUp"></param>         /// <param name="alwaysDown"></param>         public static void MoonRisetInt(int year, int month, int day, double lat, double lng, out DateTime risem, out DateTime setm,                 out bool? alwaysUp, out bool? alwaysDown)         {             DateTime dt = new DateTime(year, month, day, 0, 0, 0, DateTimeKind.Utc);               DateTime t = dt;               double hc = 0.133 * rad;             double h0 = GetMoonPosition(t, lat, lng).altitude - hc;             double h1, h2, rise = 0, set = 0, a, b, xe, ye = 0, d, x1, x2, dx;             int roots;               for (double i = 1.0; i <= 24.0; i += 2.0)             {                 h1 = GetMoonPosition(HoursLater(t, i), lat, lng).altitude - hc;                 h2 = GetMoonPosition(HoursLater(t, i + 1), lat, lng).altitude - hc;                   a = (h0 + h2) / 2 - h1;                 b = (h2 - h0) / 2;                 xe = -b / (2 * a);                 ye = (a * xe + b) * xe + h1;                 d = b * b - 4 * a * h1;                 roots = 0;                   if (d >= 0)                 {                     dx = Math.Sqrt(d) / (Math.Abs(a) * 2);                     x1 = xe - dx;                     x2 = xe + dx;                     if (Math.Abs(x1) <= 1)                     {                         roots++;                     }                       if (Math.Abs(x2) <= 1)                     {                         roots++;                     }                       if (x1 < -1)                     {                         x1 = x2;                     }                       if (roots == 1)                     {                         if (h0 < 0)                         {                             rise = i + x1;                         }                         else                         {                             set = i + x1;                         }                     }                     else if (roots == 2)                     {                         rise = i + (ye < 0 ? x2 : x1);                         set = i + (ye < 0 ? x1 : x2);                     }                       if (rise > 0 && set > 0)                     {                         break;                     }                       h0 = h2;                 }             }               risem = DateTime.MinValue;             setm = DateTime.MinValue;               if (rise > 0)             {                 risem = HoursLater(t, rise);             }               if (set > 0)             {                 setm = HoursLater(t, set);             }               alwaysUp = null; //false;//             alwaysDown = null; //false;//               if (rise < 0 && set < 0)             {                 if (ye > 0)                 {                     alwaysUp = true;                     alwaysDown = false;                     risem = DateTime.MaxValue;                     setm = DateTime.MaxValue;                 }                 else                 {                     alwaysDown = true;                     alwaysUp = false;                 }             }         }         #endregion           /// <summary>         /// 计算月亮升起和降落时间         /// </summary>         /// <param name="date"></param>         /// <param name="latitude">纬度</param>         /// <param name="longitude">经度</param>         /// <returns></returns>         public static MoonTimeResult GetMoonTime(DateTime date, double latitude, double longitude)         {             double moonrise = 0;             double moonset = 0;             DateTime dt = new DateTime(date.Year, date.Month, date.Day, 0, 0, 0, DateTimeKind.Utc);             bool? up = null;             bool? down = null;             DateTime rise;             DateTime set;             MoonRiset(dt, latitude, longitude, out rise, out set, out up, out down); //, out up, out down             DateTime moonriseTime = rise;// ToLocalTime(rise, moonrise);//             DateTime moonsetTime = set;//ToLocalTime(set, moonset); //             return new MoonTimeResult(moonriseTime, moonsetTime);         }           /// <summary>         /// 私有方法：将 UTC 时间转换为本地时间         /// </summary>         /// <param name="time"></param>         /// <param name="utTime"></param>         /// <returns></returns>           private static DateTime ToLocalTime(DateTime time, double utTime)         {             int hour = Convert.ToInt32(Math.Floor(utTime));             double temp = utTime - hour;             hour += 8; // 转换为东8区北京时间             temp = temp * 60;             int minute = Convert.ToInt32(Math.Floor(temp));             try             {                 return new DateTime(time.Year, time.Month, time.Day, hour, minute, 0);             }             catch             {                 return new DateTime(time.Year, time.Month, time.Day, 0, 0, 0);             }         }             }         /// <summary>     /// 日出日落时间结果类     /// </summary>     public class SunTimeResult     {         /// <summary>         ///         /// </summary>         public DateTime SunriseTime { get; set; }         /// <summary>         ///         /// </summary>         public DateTime SunsetTime { get; set; }           /// <summary>         ///         /// </summary>         /// <param name="sunrise"></param>         /// <param name="sunset"></param>         public SunTimeResult(DateTime sunrise, DateTime sunset)         {             SunriseTime = sunrise;             SunsetTime = sunset;         }     }       /// <summary>     /// 月亮升起和降落时间结果类     /// </summary>     public class MoonTimeResult     {           /// <summary>         ///         /// </summary>         public DateTime MoonriseTime { get; set; }         /// <summary>         ///         /// </summary>         public DateTime MoonsetTime { get; set; }         /// <summary>         ///         /// </summary>         /// <param name="moonrise"></param>         /// <param name="moonset"></param>         public MoonTimeResult(DateTime moonrise, DateTime moonset)         {             MoonriseTime = moonrise;             MoonsetTime = moonset;         }     }   }