File indexing completed on 2025-01-05 03:58:41

 // SPDX-License-Identifier: LGPL-2.1-or-later
 //
 // SPDX-FileCopyrightText: 2012 Gerhard HOLTKAMP
 //
 
 /***************************************************************************
 * Calculate Solar Eclipses                                                 *
 *                                                                          *
 *                                                                          *
 * The algorithm for the phases of the Moon and of the dates for the        *
 * equinoxes and solstices of the Sun as well as the dates of eclipses      *
 * are based on Jean Meeus "Astronomical Formulae for Calculators",         *
 * Willman-Bell, Inc., Richmond, Virginia, 1988                             *
 *                                                                          *
 * The algorithm for the Modified Julian Date and the calendar as well as   *
 * the detailed eclipse calculations are based on                           *
 * O.Montebruck and T.Pfleger, "Astronomy with a PC",                       *
 * Springer Verlag, Berlin, Heidelberg, New York, 1989                      *
 * and on the                                                               *
 * "Explanatory Supplement to the Astronomical Almanac"                     *
 * University Science Books, Mill Valley, CA, 1992                          *
 *                                                                          *
 * Open Source Code. License: GNU LGPL Version 2+                          *
 *                                                                          *
 * Author: Gerhard HOLTKAMP,        28-JAN-2013                              *
 ***************************************************************************/
 
 /*------------ include files and definitions -----------------------------*/
 #include "eclsolar.h"
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <cmath>
 #include <ctime>
 using namespace std;
 
 #include "astrolib.h"
 
 /* const double PI = 3.14159265359; */
 const double degrad = M_PI / 180.0;
 
 // ################ Solar Eclipse Class ####################
 
 EclSolar::EclSolar()
 {
  esinit();
 }
 
 EclSolar::~EclSolar()
 {
 
 }
 
 double EclSolar::atan23 (double y, double x)
  {
   /* redefine atan2 so that it doesn't crash when both x and y are 0 */
   double result;
 
   if ((x == 0) && (y == 0)) result = 0;
   else result = atan2 (y, x);
 
   return result;
  }
 
 void EclSolar::esinit()
 {
  // initialize eclipse data
   eb_start_called = false;
   eb_moonph_called = false;
   eb_lunecl = true;
   eb_lunactive = false;
   eb_local_called = false;
 
   eb_day = 1;
   eb_month = 1;
   eb_year = 2012;
   eb_hour = 0;
   eb_minute = 0;
   eb_second = 0;
   eb_tzone = 0;
   eb_del_auto = 1;
   DefTime();
   eb_time = 0;
   eb_del_tdut = DefTdUt(eb_year);
   eb_geolat = 0;
   eb_geolong = 0;
   eb_geoheight = 0;
   eb_lstcall = 0;
   eb_locecl = 0;
   eb_lastyear = -9999;
   eb_numecl = 0;
   eb_lasttz = eb_tzone;
   eb_lastdlt = eb_del_tdut;
   eb_cstep = 1.0;
   eb_cmxlat = 0;
   eb_cmxlng = 0;
   eb_penangle = 1.0;
   eb_penamode = 0;
 }
 
 void EclSolar::DefTime ()  // Get System Time and Date
  {
   time_t tt;
   int hh, mm, ss;
   double jd, hr;
 
   tt = time(NULL);
   jd = 40587.0 + tt/86400.0; // seconds since 1-JAN-1970
 
   caldat(jd, hh, mm, ss, hr);
   eb_year = ss;
   eb_month = mm;
   eb_day = hh;
 
   dms(hr, hh, mm, jd);
   eb_hour = hh;
   eb_minute = mm;
   eb_second = int(jd);
   if (eb_del_auto) eb_del_tdut = DefTdUt(eb_year);
   };
 
 int EclSolar::getYear() const
 {
   return eb_year;
 }
 
 void EclSolar::putYear(int yr)
 {
   eb_start_called = false;
   eb_moonph_called = false;
   eb_local_called = false;
   eb_lunactive = false;
 
   eb_year = yr;
   if (eb_del_auto)  eb_del_tdut = DefTdUt(eb_year);
   moonph();
 
 }
 
 int EclSolar::getNumberEclYear()
 {
  // RETURN the number of eclipses of the currently selected year
 
     int j, k;
 
     if (!eb_moonph_called) moonph();  // calculate the eclipses of the year
 
     if (eb_lunecl) return eb_numecl;
 
     k = 0;
     for (j=0; j<eb_numecl; j++)
     {
         if (eb_phase[j] > 0) k++;
     }
 
     return k;
 }
 void EclSolar::setLunarEcl(bool lecl)
 {
   // if lecl = true include lunar eclipses in addition to solar ones
   if (lecl) eb_lunecl = true;
   else eb_lunecl = false;
   eb_start_called = false;
   eb_local_called = false;
 }
 
 void EclSolar::setStepWidth(double s)
 {
   // set the step width (in minutes) used for calculations
   if (s < 0.01) eb_cstep = 0.01;
   else eb_cstep = s;
 }
 
 void EclSolar::setTimezone(double d)
 {
   // set the timezone to d (hours difference from UTC) for I/O
   eb_tzone = d;
 }
 
 void EclSolar::setDeltaTAI_UTC(double d)
 {
   // c is the difference between TAI and UTC according to the IERS
   // we have to add 32.184 sec to get to the difference TT - UT
   // which is used in the calculations here
 
   eb_del_tdut = d + 32.184;
   eb_del_auto = 0;
 }
 
 void EclSolar::setAutoTAI_UTC()
 {
   // set the difference between TAI and UTC according to the IERS
   eb_del_auto = true;
   eb_del_tdut = DefTdUt(eb_year);
 }
 
 void EclSolar::setLocalPos(double lat, double lng, double hgt)
 {
   // set the geographic coordinates for the position of the local info
   // latitude lat, longitude lng in decimal degrees
   // height hgt in meters
 
   eb_geolat = lat;
   eb_geolong = lng;
   eb_geoheight = hgt;
 
   eb_local_called = false;
 }
 
 int EclSolar::getLocalVisibility(double &mjd_start, double &mjd_stop)
 {
     // local start and stop times (MJD) for eclipse
     // RETURN 0 if not locally visible
 
     char wbuf[700];
 
     if (!eb_local_called) getLocalDetails(wbuf);
 
     mjd_start = eb_lcb1;
     mjd_stop = eb_lce1;
 
     return eb_lccnt;
 }
 
 int EclSolar::getLocalTotal(double &mjd_start, double &mjd_stop)
 {
     // local start and stop times (MJD) for totality/annularity
     // RETURN 0 if not locally visible
 
     int k, j;
     char wbuf[700];
 
     if (!eb_local_called) getLocalDetails(wbuf);
 
     mjd_start = 0;
     mjd_stop = 0;
 
     if(eb_lccnt == 0) return 0;
 
     k = 0;
     if(eb_lunactive)
     {
         for (j=0; j<eb_nphase; j++)
         {
            if ((k==0) && (eb_spp[j] > 3))
            {
                mjd_start = eb_spt[j];
                mjd_stop  = eb_ept[j];
                k = 1;
            }
         }
 
         if(mjd_start < eb_lcb1) mjd_start = eb_lcb1;
         if(mjd_start > eb_lce1) k = 0;
         if(mjd_stop > eb_lce1) mjd_stop = eb_lce1;
         if(mjd_stop < eb_lcb1) k = 0;
 
         eb_ltotb = mjd_start;
         eb_ltote = mjd_stop;
 
     }
     else k = eb_lccnt;
 
     mjd_start = eb_ltotb;
     mjd_stop = eb_ltote;
 
     return k;
 }
 
 int EclSolar::getLocalMax(double &mjdmax, double &magmax, double &elmax)
 {
 // get local (solar) eclipse maximum
 // mjdmax : Modified Julian Date of maximum eclipse
 // magmax : maximum (local) magnitude of eclipse
 // elmax : local Sun elevation at maximum
 
 // RETURN : 0 if eclipse not visible
 
 int k;
 
     mjdmax = 0;
     magmax = 0;
     elmax = 0;
 
     if (eb_lunactive) return 0;
 
     k = getLocalVisibility(mjdmax, magmax);
 
     if (k != 0)
     {
      mjdmax = eb_jdmaxps;
      magmax = eb_maxps;
      elmax = eb_maxelv;
     }
 
     return k;
 }
 
 int EclSolar::getPenumbra(double &mjd_start, double &mjd_stop)
 {
     // start and stop times (MJD) for penumbral eclipse of Moon
     // RETURN 0 if no lunar eclipse
 
     int j, k;
 
     if (!eb_start_called) eclStart();
 
     mjd_start = 0;
     mjd_stop = 0;
 
     if (!eb_lunactive) return 0;
 
     if (eb_nphase <= 0) return 0;
 
     k = 0 ;
     for (j=0; j<eb_nphase; j++)
     {
         if (eb_spp[j] == 1)
         {
             mjd_start = eb_spt[j];
             mjd_stop  =eb_ept[j];
             k = 1;
         }
     }
 
     return k;
 }
 
 int EclSolar::getPartial(double &mjd_start, double &mjd_stop)
 {
     // (global) start and stop times (MJD) for partial phase
     // RETURN 0 if no lunar eclipse
 
     int j, k;
 
     if (!eb_start_called) eclStart();
 
     mjd_start = 0;
     mjd_stop = 0;
 
     if (eb_nphase <= 0) return 0;
 
     k = 0;
 
     if(eb_lunactive)
     {
         for (j=0; j<eb_nphase; j++)
         {
            if ((k==0) && (eb_spp[j] == 3))
            {
                mjd_start = eb_spt[j];
                mjd_stop  =eb_ept[j];
                k = 1;
            }
         }
     }
     else
     {
      for (j=0; j<eb_nphase; j++)
      {
         if ((k==0) && (eb_spp[j] == 1))
         {
             mjd_start = eb_spt[j];
             mjd_stop  =eb_ept[j];
             k = 1;
         }
      }
     }
 
     return k;
 
 }
 
 int EclSolar::getTotal(double &mjd_start, double &mjd_stop)
 {
     // (global) start and stop times (MJD) for totality/annularity
     // RETURN 0 if no lunar eclipse
 
     int j, k;
 
     if (!eb_start_called) eclStart();
 
     mjd_start = 0;
     mjd_stop = 0;
 
     if (eb_nphase <= 0) return 0;
 
     k = 0;
 
     if(eb_lunactive)
     {
         for (j=0; j<eb_nphase; j++)
         {
            if ((k==0) && (eb_spp[j] > 3))
            {
                mjd_start = eb_spt[j];
                mjd_stop  =eb_ept[j];
                k = 1;
            }
         }
     }
     else
     {
      for (j=0; j<eb_nphase; j++)
      {
         if ((k==0) && (eb_spp[j] > 1))
         {
             mjd_start = eb_spt[j];
             mjd_stop  =eb_ept[j];
             k = 1;
         }
      }
     }
 
     return k;
 
 }
 
 void EclSolar::setCurrentMJD(int year, int month, int day, int hour, int min, double sec)
 {
     // set the (MJD-) time currently used for calculations to year, month, day, hour, min, sec
     // corrected for timezone
 
     double jd;
 
     jd = ddd(hour, min, sec) - eb_tzone;
     jd = mjd(day, month, year, jd);
 
     eb_lastjd = jd;
 
 }
 
 void EclSolar::getDatefromMJD(double mjd, int &year, int &month, int &day, int &hour, int &min, double &sec) const
 {
     // convert times given in Modified Julian Date (MJD) into conventional date and time
     // correct for timezone
 
     double magn;
 
     caldat((mjd + eb_tzone/24.0), day, month, year, magn);
     dms (magn,hour,min,sec);
     if (sec>30.0) min++;
     if (min>59)
      {
       hour++;
       min=0;
      };
 
 }
 
 //---------------------- getEclYearInfo--------------------------------
 
 void EclSolar::getEclYearInfo(char* wbuf)
  {
   // output the eclipse dates in buffer wbuf accurate to the minute.
 
   char dts[15];
   char outbuf[127];
   char magbuf[30];
   int j, p, kecl;
 
   if (!eb_moonph_called) moonph();  // calculate the eclipses of the year
 
   sprintf(wbuf,"Solar Eclipses for %4i  UTC +%4.1f", eb_year, eb_tzone);
 
   kecl = 1;
   for (j=0; j<eb_numecl; j++)
    {
     sprintf(dts,"%1i : ", kecl);
     strcpy (outbuf,dts);
     dtmstr((eb_eclmjd[j] + eb_tzone/24.0),dts);
     dts[12] = '\0';
     strcat (outbuf,dts);
     p = eb_phase[j];
 
     switch (p)
      {
       case 1: strcat(outbuf,"\t Partial Sun");
               sprintf(magbuf,"  (magnitude:%5.2f)",eb_magnitude[j]);
               strcat(outbuf,magbuf);
               break;
 
       case 2: strcat(outbuf,"\t non-central Annular Sun");
               break;
       case 4: strcat(outbuf,"\t Annular Sun");
               break;
 
       case 3: strcat(outbuf, "\t non-central Total Sun");
               break;
       case 5: strcat(outbuf, "\t Total Sun");
               break;
 
       case 6: strcat(outbuf, "\t Annular/Total Sun");
               break;
 
       case -1:
       case -2: strcat(outbuf, "\t Penumbral Moon");
                sprintf(magbuf,"  (magnitude:%5.2f)",eb_magnitude[j]);
                strcat(outbuf,magbuf);
                break;
 
       case -3: strcat(outbuf, "\t Partial Moon");
                sprintf(magbuf,"  (magnitude:%5.2f)",eb_magnitude[j]);
                strcat(outbuf,magbuf);
                break;
 
       case -4: strcat(outbuf, "\t Total Moon");
                sprintf(magbuf,"  (magnitude:%5.2f)",eb_magnitude[j]);
                strcat(outbuf,magbuf);
                break;
      };
 
     if ((p > 0) || eb_lunecl)  // solar eclipse only or also lunar eclipses
      {
       strcat (wbuf, "\n");
       strcat (wbuf, outbuf);
       kecl++;
      };
    }
  }
 
 int EclSolar::getEclYearInfo(int k, int &yr, int &month, int &day,
                              int &hour, int &min, double &sec, double &tzone, double &magn)
 {
   /* output the eclipse info for k-th eclipse
 
      year, month, day, hour, minutes, seconds and timezone
      magn = magnitude of eclipse
 
    RETURN: phase of eclipse. 0 if no k-th eclipse
 
       1: Partial Sun
       2: non-central Annular Sun
       3: non-central Total Sun
       4: Annular Sun
       5: Total Sun
       6: Annular/Total Sun
 
      -1, -2: Penumbral Moon
      -3: Partial Moon
      -4: Total Moon
 
  */
   bool nls;
   int j, p, kecl;
 
   nls = true;
 
   if (!eb_moonph_called) moonph();  // calculate the eclipses of the year
 
   if (k < 1)
   {
       k = eb_eclselect;  // select current eclipse as default
       nls = false;
   };
   if ((k < 1) && (k > eb_numecl)) return 0;
 
   p = k - 1;
   if (nls && (!eb_lunecl))
   {
    kecl = 0;
    p = -1;
    for(j=0; j<eb_numecl; j++)
    {
        if (eb_phase[j] > 0)
        {
            kecl++;
            if (kecl == k) p = j;
        };
    };
   };
 
   if (p < 0) return 0;
 
   j = p;
 
   // convert MJD into corresponding date and time
   caldat((eb_eclmjd[j] + eb_tzone/24.0), day, month, yr, magn);
   dms (magn,hour,min,sec);
   if (sec>30.0) min++;
   if (min>59)
    {
     hour++;
     min=0;
    };
 
   magn = eb_magnitude[j];
   tzone = eb_tzone;
 
   return eb_phase[j];
 }
 
 int EclSolar::getEclTxt (int k, char* jtxt)
  {
   // get the data / kind of eclipse info for the j-th eclipse
   // and place it into jtxt
 
     // RETURN : the phase of the eclipse. 0 if no j-th eclipse
 
   int p, j;
   char dts[13];
 
   if (!eb_moonph_called) moonph();  // calculate the eclipses of the year
 
   if (k < 1) k = eb_eclselect;  // select current eclipse as default
   if ((k < 1) && (k > eb_numecl)) return 0;
 
   j = k-1;
 
   sprintf(jtxt, "%2i :", (j+1));
   sprintf(dts, "%5i ", eb_year);
   strcat (jtxt, dts);
   dtmstr((eb_eclmjd[j]+eb_tzone/24.0),dts);
   dts[6] = '\0';
   strcat (jtxt,dts);
 
   p = eb_phase[j];
   switch (p)
    {
     case 1: strcat(jtxt," Par.Sun");
             break;
     case 2: strcat(jtxt, " non-centr.Ann.Sun");
             break;
     case 4: strcat(jtxt," Ann.Sun");
             break;
     case 3: strcat(jtxt," non-centr.Tot.Sun");
             break;
     case 5: strcat(jtxt," Tot.Sun");
             break;
     case 6: strcat(jtxt," Ann/Tot.");
             break;
 
     case -1:
     case -2: strcat(jtxt," Pen.Moon");
              break;
     case -3: strcat(jtxt," Par.Moon");
              break;
     case -4: strcat(jtxt," Tot.Moon");
              break;
    };
 
   return p;
  }
 
 // ----------------------------- Select Eclipse -------------------------
 
 void EclSolar::putEclSelect(int es)
 {
  // store the number of the eclipse selected for detailed calculations
  int k, j;
 
  if (!eb_moonph_called) moonph();  // calculate the eclipses of the year
 
  k = 0;
 
  eb_lunactive = false;
  eb_eclselect = 1;
  for (j=0; j<eb_numecl; j++)
   {
    if ((eb_phase[j] > 0) || eb_lunecl)  // only solar eclipses if set
     {
      k++;
      if (k == es)
      {
          eb_eclselect = j + 1;
          if (eb_phase[j] < 0) eb_lunactive = true;
      };
     };
   };
  eb_start_called = false;
 }
 
 void EclSolar::nextEcl()
 {
  // select the next eclipse for detailed calculations
  int k, j, es;
 
  if (!eb_moonph_called) moonph();  // calculate the eclipses of the year
  eb_start_called = false;
 
  k = eb_eclselect + 1;
  if (k > eb_numecl)
  {
      k = eb_year + 1;
      putYear (k);
      k = 1;
      putEclSelect(k);
 
      return;
  };
 
  if (eb_lunecl)  // easier when lunar eclipses are included
  {
      putEclSelect(k);
 
      return;
  };
 
  eb_lunactive = false;
 
  es = eb_eclselect;
  k = 0;
  for (j=es; j<eb_numecl; j++)
  {
     if ((k == 0) && (eb_phase[j] > 0)) k = j + 1;
  };
 
  if(k > 0)
  {
     eb_eclselect = k;
     return;
  }
 
  k = eb_year + 1;
  putYear (k);
  es = 1;
  putEclSelect(es);
 
 }
 
 void EclSolar::previousEcl()
 {
  // select the previous eclipse for detailed calculations
  int k, j, es;
 
  if (!eb_moonph_called) moonph();  // calculate the eclipses of the year
  eb_start_called = false;
 
  k = eb_eclselect - 1;
 
  if (k <= 0)
  {
      k = eb_year - 1;
      putYear (k);
      k = eb_numecl;
  };
 
  if (eb_lunecl)  // easier when lunar eclipses are included
  {
      putEclSelect(k);
 
      return;
  };
 
  eb_lunactive = false;
 
  es = 0;
  k--;
  for (j=k; j>=0; j--)
  {
      if ((es == 0) && (eb_phase[j] > 0)) es = j + 1;
  };
 
  if(es > 0) eb_eclselect = es;
  else putEclSelect(0);  // this case should never happen!
 
 }
 
 double EclSolar::getLastMJD() const
 {
  // RETURN the MJD last used in calculations
 
     return eb_lastjd;
 }
 
 void EclSolar::setPenumbraAngle(double pa, int mode)
 {
     /* set the Penumbra Angle
        if mode == 0 the angle will be set to pa-times the maximum angle
        (pa < 1.0). Set pa = 1 for the normal penumbra boundaries
 
        if mode == 1 the angle will be set such that the penumbra line
        markes magnitude pa. pa == 0 will mark normal penumbra boundaries
 
        if mode == 2 the angle will be set such that the penumbra line
        markes the obscuration pa. pa == 0.5 will mean that 50% of the Sun's
        disk is covered by the Moon etc.
     */
 
     double mjd, dpn1, dpn2, pan1, pan2;
     double mag, m1, m2, s, ps;
     int j;
     Vec3 ubm, ube;
     Eclipse eclp;
 
     if (mode == 0)
     {
         eb_penangle = pa;
         eb_penamode = 0;
         if (pa > 1.0) eb_penangle = 1.0;
         if (pa < 0) eb_penangle = 1.0;
 
         return;
     }
 
     if (!eb_start_called) eclStart();
 
     if (mode == 1)
     {
         eb_penamode = 1;
         mjd = eb_eclmjd[eb_eclselect-1];
         eclp.umbra (mjd, eb_del_tdut, ubm, ube, dpn1, pan1);
         eclp.penumd (mjd, eb_del_tdut, ubm, ube, dpn2, pan2);
 
         if(dpn2 > 0)
         {
             eb_penangle = fabs(pa);
             if(eb_penangle > 1.0) eb_penangle = 1.0;
             eb_penangle = 1.0 - eb_penangle * (1.0 + dpn1 / dpn2);
         }
         else eb_penangle = 1.0;
 
         return;
     }
 
     if (mode == 2)
     {
         eb_penamode = 2;
         mjd = eb_eclmjd[eb_eclselect-1];
         eclp.umbra (mjd, eb_del_tdut, ubm, ube, dpn1, pan1);
         eclp.penumd (mjd, eb_del_tdut, ubm, ube, dpn2, pan2);
 
         ps = pa;  // find the magnitude that corresponds to the obscuration
         if (ps > 1.0) ps = 1.0;
         if (ps < 0) ps = 0;
         for (j=1; j<11; j++)
         {
             mag = double(j) * 0.1;
             s = sunObscure(dpn2, dpn1, mag);
             if (s >= ps) break;
         }
 
         m1 = mag - 0.1;
         m2 = mag;
         for (j=0; j<8; j++)  // 8 iterations should be plenty
         {
            mag = (m2 + m1) * 0.5;
            s = sunObscure(dpn2, dpn1, mag);
            if (s > ps) m2 = mag;
            else m1 = mag;
         }
 
         if(dpn2 > 0)
         {
             eb_penangle = fabs(mag);
             if(eb_penangle > 1.0) eb_penangle = 1.0;
             eb_penangle = 1.0 - eb_penangle * (1.0 + dpn1 / dpn2);
         }
         else eb_penangle = 1.0;
 
         return;
     }
 
     eb_penamode = 0;
     eb_penangle = 1.0;
 
 }
 
 // -------- auxiliary functions --------------------------------
 void EclSolar::GetMonth (int mm, char* mchr)
  {
   // get three letter designation of month
   // mm is the number of the month
   // mchr is a char[4] array to receive the three letters of the month
 
   switch (mm)
    {
     case 1 : strcpy(mchr,"JAN"); break;
     case 2 : strcpy(mchr,"FEB"); break;
     case 3 : strcpy(mchr,"MAR"); break;
     case 4 : strcpy(mchr,"APR"); break;
     case 5 : strcpy(mchr,"MAY"); break;
     case 6 : strcpy(mchr,"JUN"); break;
     case 7 : strcpy(mchr,"JUL"); break;
     case 8 : strcpy(mchr,"AUG"); break;
     case 9 : strcpy(mchr,"SEP"); break;
     case 10 : strcpy(mchr,"OCT"); break;
     case 11 : strcpy(mchr,"NOV"); break;
     case 12 : strcpy(mchr,"DEC"); break;
     default: strcpy(mchr,"ERR");
    };
 }
 
 double EclSolar::phmjd (double yearf, double phase, double tdut,
                   int& eph, double& ejd, double& emag)
   /*
     Calculate the Modified Julian Date of the occurrence of the specified
     phase of the Moon and check for possible eclipses.
     yearf : year.fraction of date close to the Moon phase
     phase : 0    for New Moon,
             0.25 for First Quarter,
             0.5  for Full Moon,
             0.75 for Last Quarter.
     tdut = TDT - UT in sec
 
     RETURN: the MJD of the lunar phase event
 
     OUTPUT:
     eph : phase of the eclipse on that date
           0 = no eclipse, 1 = partial solar eclipse,
           2 = non-central annular, 3 = non-central total
           4 = annular solar, 5 = total solar,
           6 = annular/total solar, -1 =partial penumbral lunar,
           -2 = total penumbral lunar, -3 = partial umbral lunar,
           -4 = total umbral lunar
     ejd : Modified Julian Date of the maximum of the eclipse (if any)
     emag : magnitude of the eclipse (if any)
   */
  {
   double tt, jd, k, m, p, f;
   double s, c, gam, u;
   int tst;
   Eclipse eclp;
 
   // preliminary (modified) Julian Date
   k = floor ((yearf - 1900.0) * 12.3685) + phase;
   tt = k / 1236.85;
   jd = 166.56 + (132.87 - 0.009173*tt)*tt;
   jd = 15020.25933 + 29.53058868*k
                    + (0.0001178 - 0.000000155*tt)*tt*tt
                    + 0.00033 * sin (degrad*jd);
 
   eph = 0;   // assume no eclipse
 
   // Sun's mean anomaly
   m = degrad * (359.2242 + 29.10535608*k
                - (0.0000333 - 0.00000347*tt)*tt*tt);
   // Moon's mean anomaly
   p = degrad * (306.0253 + 385.81691808*k
               + (0.0107306 + 0.00001236*tt)*tt*tt);
   // 2* Moon's argument of latitude
   f = 2.0 * degrad * (21.2964 + 390.67050646*k
                    - (0.0016528 - 0.00000239*tt)*tt*tt);
 
   if ((phase == 0) || (phase == 0.5))  // for Full and New Moon
    {
     k = (0.1734 - 0.000393*tt) * sin (m)
         + 0.0021 * sin (2.0 * m)
         - 0.4068 * sin (p)
         + 0.0161 * sin (2.0 * p)
         - 0.0004 * sin (3.0 * p)
         + 0.0104 * sin (f)
         - 0.0051 * sin (m + p)
         - 0.0074 * sin (m - p)
         + 0.0004 * sin (f + m)
         - 0.0004 * sin (f - m)
         - 0.0006 * sin (f + p)
         + 0.0010 * sin (f - p)
         + 0.0005 * sin (m + 2.0*p);
 
     // check for possible eclipses.
     f = f / 2.0;
     if (fabs(sin(f)) <= 0.36)   // eclipses are possible
      {
       ejd = (0.1734 - 0.000393*tt) * sin(m)
             + 0.0021 * sin(2.0*m)
             - 0.4068 * sin(p)
             + 0.0161 * sin(2.0*p)
             - 0.0051 * sin(m+p)
             - 0.0074 * sin(m-p)
             - 0.0104 * sin(2.0*f);
       ejd += jd;
 
       s = 5.19595 - 0.0048*cos(m) + 0.0020*cos(2.0*m) - 0.3283*cos(p)
                   - 0.0060*cos(m+p) + 0.0041*cos(m-p);
 
       c = 0.2070*sin(m) + 0.0024*sin(2.0*m) - 0.0390*sin(p)
                         + 0.0115*sin(2.0*p) - 0.0073*sin(m+p)
                         - 0.0067*sin(m-p) + 0.0117*sin(2.0*f);
 
       gam = s*sin(f) + c*cos(f);
       u = 0.0059 + 0.0046*cos(m) - 0.0182*cos(p)
                  + 0.0004*cos(2.0*p) - 0.0005*cos(m+p);
 
       if (phase == 0)          // check for solar eclipse
        {
         if (fabs(gam) <= (1.5432+u))
          {
           if (fabs(gam) < 0.9972)    // central eclipse
            {
             emag = 1.0;
             if (u < 0) eph = 5;  // total eclipse
             else
              {
               if (u > 0.0047) eph = 4;  // annular eclipse
               else
                {
                 if (u < (0.00464*cos(asin(gam)))) eph = 6; // annular/total
                 else eph = 4;  // annular
                }; // end if u>0.0047
              }; // end if u<0
            }  // end if fabs(gam) if
           else      // non-central eclipse
            {
             eph = 1;   // assume partial eclipse
             if (fabs(gam) < (0.9972+fabs(u))) // non-central annular or total
              {
               eph = eclp.solar(ejd,tdut,s,c);
               emag = 1.0;
              };
             if (eph == 1)     // get magnitude of partial eclipse
                 emag = (1.5432 + u - fabs(gam)) / (0.5460 + 2.0*u);
             if (emag < 0.025) // check if low mag eclipse is OK
              {
               eph = 0;
               u = 1.0 / 720; // 2 min steps
               for (int j=0; j < 288; j++)
                {
                 tt = ejd - 0.2 + double(j)*u;
                 tst = eclp.solar(tt,tdut,s,c);
                 if (tst > 0) eph = tst;
                };
              };
            }
          }
        } // end of solar eclipse check
 
       if (phase == 0.5)        // check for lunar eclipse
        {
         c = (1.5572 + u - fabs(gam)) / 0.5450;
         if (c > 0)
          {
           s = (1.0129 - u - fabs(gam)) / 0.5450;
           if (s < 0)   // penumbral eclipse
            {
             emag = c;
             if (emag > 1) eph = -2;
             else eph = -1;
            }
           else         // umbral eclipse
            {
             emag = s;
             if (emag > 1) eph = -4;
             else eph = -3;
            }
          }
        }
      }
    };
 
   if ((phase == 0.25) || (phase == 0.75)) // for first and last quarter
    {
     k = (0.1721 - 0.0004*tt) * sin (m)
         + 0.0021 * sin (2.0 * m)
         - 0.6280 * sin (p)
         + 0.0089 * sin (2.0 * p)
         - 0.0004 * sin (3.0 * p)
         + 0.0079 * sin (f)
         - 0.0119 * sin (m + p)
         - 0.0047 * sin (m - p)
         + 0.0003 * sin (f + m)
         - 0.0004 * sin (f - m)
         - 0.0006 * sin (f + p)
         + 0.0021 * sin (f - p)
         + 0.0003 * sin (m + 2.0*p)
         + 0.0004 * sin (m - 2.0*p)
         - 0.0003 * sin (2.0*m + p);
     if (phase == 0.25)
      {
       k += 0.0028 - 0.0004*cos(m) + 0.0003*cos(p);
      };
     if (phase == 0.75)
      {
       k += -0.0028 + 0.0004*cos(m) - 0.0003*cos(p);
      };
    };
 
   jd = jd + k;
 
   return jd;
  }
 
 void EclSolar::ckphase (double minmjd, double maxmjd, double yr,
               double deltdut, int &mp, PMJD p, double phase)
   /* calculate the respective phase for one (MJD-) date and check whether
      this date is within the limits given by minmjd and maxmjd.
      Use yr as the year.fraction close to the desired date.
      If the date is within the limits store the result in the
      respective array.
      Also check for possible occurrences of eclipses and store the
      respective data in an array
   */
  {
   double td, ejd, emag;
   int j, eph;
 
   td = phmjd (yr, phase, deltdut*86400.0, eph, ejd, emag);
   // correct difference between UT and TDT
   td = td - deltdut;  // correct for difference between TDT and UT.
 
   // check whether the date is within the respective year
 
   if ((td >= minmjd) &&  (td <= maxmjd) && (mp < MAXLUN))
    {
     if (mp==0)
      {
       p[0]=td;
       mp=1;
      }
     else
      {
       if (p[mp-1] < (td - 0.1))
        {
         p[mp]=td;
         mp=mp+1;
        };
      };
    };
 
   // now the eclipses
   if (eph != 0)
    {
     td = ejd;
     td = td - deltdut;  // correct for difference between TDT and UT.
 
     // check whether the date is within the respective year
     if ((td >= minmjd)&&(td <= maxmjd)&&(eb_numecl<GBL_ECLBUF))
      {
       if (eb_numecl == 0)
        {
         eb_eclmjd[0] = td;
         eb_magnitude[0] = emag;
         eb_phase[0] = eph;
         eb_numecl = 1;
        }
       else
        {
         for (j=0; j<eb_numecl; j++)
          {          // check whether the date is already stored
           if (fabs(eb_eclmjd[j]- td) < 0.01) eph = 0;
          };
         if (eph != 0)
          {
           j = eb_numecl;
           eb_eclmjd[j] = td;
           eb_magnitude[j] = emag;
           eb_phase[j] = eph;
           eb_numecl += 1;
          };
        }
      }
    }
  }
 
 void EclSolar::dtmstr(double jdmoon, char *dts)
 //  Convert the Modified Julian Date jdmoon into a corresponding string
 //  *dts which has the format "MMM DD HH:MM"
 {
   int dd, mm, yy, deg, mnt;
   double hh, sec;
   char mchr[4];
 
   // convert MJD into corresponding date and time
   caldat(jdmoon, dd, mm, yy, hh);
   dms (hh,deg,mnt,sec);
   if (sec>30.0) {mnt++;};
   if (mnt>59)
    {
     deg++;
     mnt=0;
    };
 
   // store data in their positions
   GetMonth (mm, mchr);
   dts[0]=mchr[0];
   dts[1]=mchr[1];
   dts[2]=mchr[2];
   dts[3]=' ';
   sprintf(&dts[4],"%2i %2i:%02i", dd, deg, mnt);
   dts[12]=' ';
 }
 
 //------------------------- moonph ---------------------------------
 
 void EclSolar::moonph()
 {
   int mp0, mp25, mp5, mp75;  // counter of respective phase entries
   PMJD p0, p25, p5, p75;
   int day, month, year, j;
   double yr, yx, hour, deltdut;
   double minmjd, maxmjd;
   double glatsv, glongsv, gheightsv, lat, lng;
   char wbuf[700];
 
   eb_moonph_called = true;
 
 // assign input data from Window Input Structure
   year = eb_year;
   deltdut = eb_del_tdut / 86400.0;  // difference TDT - UT in days
   eb_lastyear = year;
   eb_lasttz = eb_tzone;
   eb_lastdlt = eb_del_tdut;
 
 // initializing counters
   eb_numecl = 0;
   mp0 = 0;
   mp25 = 0;
   mp5 = 0;
   mp75 = 0;
 
   yr = year - 0.2;
   yx = year + 1.2;
   day = 1;
   month = 1;
   hour = 0;
   minmjd = mjd(day, month, year, hour);
   day = 31;
   month = 12;
   hour = 24.0;
   maxmjd = mjd(day, month, year, hour);
 
   /* As the function phmjd finds the respective phases of the Moon
      only to within a few weeks of the time given by the input
      parameter (year.faction) the following loop starts well ahead of
      the beginning of the year in question and ends well after.
      The time step of two weeks utilized to increment the year.fraction
      parameter assures that we catch all the different lunations */
 
   while (yr < yx)
    {                      // calculate and check the phases
     ckphase(minmjd,maxmjd,yr,deltdut, mp0, p0, 0.0);
     ckphase(minmjd,maxmjd,yr,deltdut, mp25, p25, 0.25);
     ckphase(minmjd,maxmjd,yr,deltdut, mp5, p5, 0.5);
     ckphase(minmjd,maxmjd,yr,deltdut, mp75, p75, 0.75);
     yr+=0.02;  // increase by 1/50th of a year (about two weeks)
    };
 
   for (j=0; j<eb_numecl; j++)
   {
       if( (eb_phase[j] == 1) && (eb_magnitude[j] > 0.98))  // check for possible non-central eclipse
       {
           glatsv = eb_geolat;
           glongsv = eb_geolong;
           gheightsv = eb_geoheight;
           eb_eclselect = j+1;
           eb_start_called = false;
           eb_local_called = false;
 
           getMaxPos (lat, lng);
           eb_geolat = lat;
           eb_geolong = lng;
           eb_geoheight = 0;
 
           getLocalDetails(wbuf);
 
           if ((eb_spp[0] == 2) || (eb_spp[1] == 2)) eb_phase[j] = 2;
           if ((eb_spp[0] == 3) || (eb_spp[1] == 3)) eb_phase[j] = 3;
 
           eb_geolat = glatsv;
           eb_geolong = glongsv;
           eb_geoheight = gheightsv;
           eb_start_called = false;
           eb_local_called = false;
 
       }
 
   };
 
   eb_eclselect = 0;
 }
 
 double EclSolar::getlocmag(double jd, double ep2, double phi, double lamda,
                  double height, const Vec3& rs, const Vec3& rm, int& totflg)
  {
   /* get magnitude of solar eclipse at local position.
      jd : MJD (UT) of event
      ep2 : correction for apparent sidereal time (in sec)
      phi, lamda : latitude and longitude of observer in radians
      height : height of observer in m
      rs, rm : geocentric position vector of the sun and the moon
      totflg : 1 if total or annular, 0 otherwise
 
      RETURN: The magnitude of the eclipse (0 if no eclipse)
   */
 
   const double ds = 218.245445;  // diameter of Sun in Earth radii
   const double dm = 0.544986;   // diameter of Moon in Earth radii
   Vec3  gm, gs, s;
   double dsun, dmoon, asep;
   double elev;
 
   gm = GeoPos(jd, ep2, phi, lamda, height);
   gs = rs - gm;
   gm = rm - gm;
 
   // correct for refraction
   s = EquHor(jd, ep2, phi, lamda, gs);
   s = carpol(s);
   elev = s[2];
 
   if (elev > -3.5e-2)   // cutoff of -2 deg for calculating refraction
    {
     elev = Refract(elev);
     s[2] = s[2] + elev;
     s = polcar (s);
     gs = HorEqu(jd, ep2, phi, lamda, s);
    };
 
   s = EquHor(jd, ep2, phi, lamda, gm);
   s = carpol(s);
   elev = s[2];
   if (elev > -3.5e-2)   // cutoff of -2 deg for calculating refraction
    {
     elev = Refract(elev);
     s[2] = s[2] + elev;
     s = polcar (s);
     gm = HorEqu(jd, ep2, phi, lamda, s);
    };
 
   dsun = atan(0.5*ds/abs(gs)); // apparent radius of the Sun
   dmoon = atan(0.5*dm/abs(gm)); // apparent radius of the Moon
 
   gs = vnorm(gs);
   gm = vnorm(gm);
   asep = fabs(dot(gs, gm));
   if (asep > 1.0) asep = 1.0;
   asep = acos(asep);    // apparent distance between Sun and Moon
 
   totflg = 0;
   if ((dsun+dmoon) > asep)  // we have an eclipse
    {
     if (fabs(dsun-dmoon) > asep) totflg = 1;
     asep = fabs(dsun + dmoon - asep) / (2.0 * dsun);
    }
   else asep = 0;
 
   return asep;
  }
 
 //------------------------- eclStart ---------------------------------
 
 void EclSolar::eclStart()
 {
   /* get start and end times of the various phases of the eclipse
      j = index of the eclipse
      eb_spt[i] = start time in MJD for phase i
      eb_ept[i] = end time in MJD for phase i
      eb_spp[i] = kind of phase i
 
      Also set the global eb_jdstart and eb_jdstop
      to the (global jd times) of eclipse start and end.
 
    */
   int nump, eflg, pcur, pold, maxp, i, j, npflg, p;
   double jd, step, jd2, jdf, d1, d2;
   double azim, elev, dist, phi, lamda;
   bool eclstarted;
   Vec3 gx;
   Eclipse eclp;
 
   if (!eb_moonph_called)  // just in case - this should never happen!
   {
       moonph();
       putEclSelect(1);
   };
 
   eb_local_called = false;
   eb_start_called = true;
 
   j = eb_eclselect-1;
 
   eclstarted = false;
   nump = 0;
   maxp = 0;
   eflg = 0;  // end flag
   pold = 0;
   elev = 0;
   eb_maxps = -1.0;
   eb_maxelv = -1.0;
   p = eb_phase[j];
   jd = eb_eclmjd[j] - 0.5;  // start 12 hours before maximum
   jdf = jd + 1.5;  // emergency stop if something goes wrong with the loop
   step = eb_cstep / (24.0*60.0);  // stepwidth (best set to 1 minute)
 
   do
    {
      if (eb_lunactive) pcur = eclp.lunar(jd, eb_del_tdut);
      else pcur = eclp.solar (jd, eb_del_tdut,d1, d2);
     // now check the start and stop times for the phases
     if (pcur > pold)
      {
       eclstarted = true;
       if(nump < 4)
        {
         eb_spt[nump] = jd;
         eb_spp[nump] = pcur;
         nump++;
         maxp++;
         pold = pcur;
         // get time accurate to the second
         jd2 = jd - 1.0/86400.0;  // go in seconds steps
         for (i=0; i<60; i++)
         {
             if (eb_lunactive) pcur = eclp.lunar(jd, eb_del_tdut);
             else pcur = eclp.solar (jd2, eb_del_tdut,d1, d2);
 
             if (pcur == pold) eb_spt[nump] = jd2;
             else break;
             jd2 = jd2 - 1.0/86400.0;  // go in seconds steps
         };
        }
      }
     else if (eclstarted && (pcur < pold))
      {
         pold = pcur;
         // get time accurate to the second
         jd2 = jd - 1.0/86400.0;  // go in seconds steps
         for (i=0; i<60; i++)
         {
             if (eb_lunactive) pcur = eclp.lunar(jd, eb_del_tdut);
             else pcur = eclp.solar (jd2, eb_del_tdut,d1, d2);
             if (pcur == pold) jd = jd2;
             else break;
             jd2 = jd2 - 1.0/86400.0;  // go in seconds steps
         };
         pcur = pold;
 
       npflg = 1;
       if (nump > 1)
        {
         if (pcur > eb_spp[nump-2]) npflg = 0;
        }
       if (npflg)
        {
         nump--;
         if (nump >= 0) eb_ept[nump] = jd;
         if (nump > 1)
          {
           if (pcur < eb_spp[nump-1])
            {
             nump--;
             eb_ept[nump] = jd;
            }
          }
         if (nump <= 0) eflg = 1;
        }
      };
 
     jd += step;
     if (jd > jdf) eflg = 1;
 
    } while (eflg != 1);
 
   // now check for maximum eclipse conditions
 
   calcMaxPos(phi, lamda);
 
   if ((eb_lunactive == false) && (p > 3))  // central solar eclipse
   {
       eb_jdmaxps = eb_eclmjd[j];
       jd = eb_eclmjd[j] - 600.0/86400.0;  // start 10 min before approximate max time
       phi = eb_cmxlat * degrad;
       lamda = eb_cmxlng * degrad;
       for (i=0; i<1200; i++)
       {
           jd += 1.0/86400.0;  // go in seconds steps
           pcur = eclp.solar (jd, eb_del_tdut,d1, d2);
           if (pcur > 3)
           {
               gx = eclp.GetRSun();
               AppPos (jd, eclp.GetEp2(), d1, d2, 0.0, 1, gx, azim, elev, dist);
 
               if (elev > eb_maxelv)
               {
                 eb_maxelv = elev;
                 eb_jdmaxps = jd;
                 phi = d1;
                 lamda = d2;
                };
           }
       }
       eb_maxelv = elev / degrad;
       eb_cmxlat = phi / degrad;
       eb_cmxlng = lamda / degrad;
       if (eb_cmxlng < 0) eb_cmxlng += 360.0;
   };
 
   eb_jdstart = eb_spt[0];
   eb_jdstop = eb_ept[0];
   eb_nphase = maxp;
 
  }
 
 void EclSolar::calcMaxPos(double &lat, double &lng)
  {
   // Get the geographic position of the maximum eclipse
   // in case of a central eclipse the position is approximate
   // lat and lng are in decimal degrees
 
   int j, p;
   double t, mp2;
   Vec3 rm;
   Vec3 s2;
   Eclipse eclp;
 
   mp2 = 2.0 * M_PI;
 
   j = eb_eclselect-1;
 
   t = eb_eclmjd[j];
 
   if (eb_lunactive)
   {
       eclp.lunar(t, eb_del_tdut);
       rm = eclp.GetRMoon();
 
       // get sub lunar point at maximum
       s2 = carpol(rm);
       lat = s2[2];   // just preliminary
       lng = s2[1] - lsidtim (t, 0, eclp.GetEp2())*M_PI/12.0;
       if (lng > mp2) lng -= mp2;
       if (lng < -M_PI) lng += mp2;
       if (lng > M_PI) lng -= mp2;
       if (fabs(lat) < 1.53589) lat = atan(1.00674*tan(lat));
       lat /= degrad;
       lng /= degrad;
       if (lng < 0) lng += 360.0;
       eb_cmxlat = lat;
       eb_cmxlng = lng;
       return;
   }
   else p = eclp.solar(t,eb_del_tdut,lat,lng);
 
   if (p > 3)
    {
     eb_cmxlat = lat;
     eb_cmxlng = lng;
     eb_cmxlat /= degrad;
     eb_cmxlng /= degrad;
    }
   else
    {
     eclp.maxpos(t,eb_del_tdut,eb_cmxlat,eb_cmxlng);
     eb_cmxlat /= degrad;
     eb_cmxlng /= degrad;
    };
 
   if (eb_cmxlng < 0) eb_cmxlng += 360.0;
   lat = eb_cmxlat;
   lng = eb_cmxlng;
  }
 
 void EclSolar::getMaxPos(double &lat, double &lng)
  {
   // Get the geographic position of the maximum eclipse
 
   if (!eb_start_called) eclStart();
 
   lat = eb_cmxlat;
   lng = eb_cmxlng;
  }
 
 double EclSolar::sunObscure(double l1, double l2, double mag)
 {
     // get the Obscuration of the Sun from penumbra l1, umbra l2 and
     // magnitude mag
 
     double s, a, b, c, m;
 
     m = l1 - mag * (l1 + l2);
     s = (l1 - l2) / (l1 + l2);
     c = (l1*l1 + l2*l2 - 2*m*m) / (l1*l1 - l2*l2);
     c = acos(c);
     b = (l1*l2 + m*m) / (m*(l1+l2));
     b = acos(b);
     a = M_PI - (b + c);
     s = (s*s*a + b) - s * sin(c);
 
     return s / M_PI;
 }
 
 /*------------------------- EclCentral ---------------------------------*/
 
 int EclSolar::eclPltCentral(bool firstc, double &lat, double &lng)
  {
   /* get next coordinates for central eclipse position
      first = 1 for first call (first point will be found)
      lat, lng : latitude and longitude in decimal degrees
 
      RETURN: phase (= 4 annular, = 5 total, = 6 annular/total
                     0 if there was no central eclipse)
   */
   double phi, lamda, d1, d2, jd, jd2;
   int kp, kp2, i;
   Eclipse eclp;
 
   if (!eb_start_called) eclStart();
 
   if (eb_lunactive)  // just in case
    {
     eb_finished2 = true;
     lat = 0.0;
     lng = 0.0;
     return 0;
    };
 
   eb_cphs = 0;
 
   if (firstc)   // find the first occurrence compliant with the step width
    {
     jd = eb_jdstart;
     kp = eclp.solar(jd, eb_del_tdut, phi, lamda);
 
     while ((kp < 4) && (jd < eb_jdstop))
      {
       jd += double(eb_cstep) / (24.0*60.0);
       eb_lastjd = jd;
       kp = eclp.solar(jd, eb_del_tdut, phi, lamda);
      };
 
     jd2 = jd;
     for (i=0; i<60; i++)  // get it right to the second
     {
         jd2 = jd2 - 1.0/86400.0;  // go in seconds steps
         kp2 = eclp.solar (jd2, eb_del_tdut,d1, d2);
         if (kp2 == kp)
         {
             phi = d1;
             lamda = d2;
         }
         else break;
     };
     eb_finished2 = false;
 
    }  // end of firstc
   else
    {
     if (eb_finished2) return 0;
 
     jd = eb_lastjd + double(eb_cstep) / (24.0*60.0);
     eb_lastjd = jd;
     if (jd > eb_jdstop)
     {
         eb_finished2 = true;
         return 0;
     };
 
     kp = eclp.solar(jd, eb_del_tdut, phi, lamda);
 
     if (kp <= 3)  // end of central eclipse.
     {
      eb_finished = true;
      for (i=0; i<60; i++)  // get it right to the second
      {
         jd-= 1.0/86400.0;  // go in seconds steps
         kp = eclp.solar (jd, eb_del_tdut, phi, lamda);
         if (kp > 3) break;
      };
     };
    };
 
   if (kp > 3)   // central eclipse
    {
     eb_cphs = kp;
 
     phi /= degrad;
     lamda /= degrad;
     if (lamda < 0.0) lamda += 360.0;
     if (lamda > 360.0) lamda -= 360.0;
     eb_clat = phi;
     eb_clng = lamda;
     lat = eb_clat;
     lng = eb_clng;
 
     //  djd = eclp.duration(jd, indata->del_tdut, width);
    }
   return kp;
  }
 
 //--------------------Northern and Southern Boundaries -------------------------
 
 void EclSolar::InitBound()
  {
   /* Initialize the calculation for the northern and southern boundaries
      of solar eclipses (umbra or penumbra).
      The function EclStart must have been called first to enable InitBound
      to get the right eclipse.
      The calculation is done in Earth radii.
 
      OUTPUT:
             eb_ubm : Penumbra base vector
             eb_ube : Shadod base vector for upper boundary
             eb_udm : Penumbra base delta vector
             eb_ude : Shadow delta vector for upper boundary
             eb_lbe : Shadod base vector for lower boundary
             eb_lde : Shadow delta vector for lower boundary
   */
 
 //  const double dm = 0.272493;   // radius of Moon in Earth radii
   double dpn1, dpn2, pan1, pan2, s0;
   Vec3 shmv, u2m, u2e;
   Vec3 ax1, ax2;
   Eclipse eclp;
 
   if (!eb_start_called) eclStart();
   if (eb_lunactive) return;  // only for solar eclipses
 
   // beginning of the eclipse
   eclp.penumd (eb_jdstart, eb_del_tdut, eb_ubm, eb_ube, dpn1, pan1);
 
   // end of the eclipse
   eclp.penumd (eb_jdstop, eb_del_tdut, u2m, u2e, dpn2, pan2);
 
   dpn1 *= 0.5;
   dpn2 *= 0.5;
 
   if (eb_penamode == 0)
   {
     dpn1 *= eb_penangle;
     pan1 *= eb_penangle;
     dpn2 *= eb_penangle;
     pan2 *= eb_penangle;
   }
 
   if (eb_penamode > 0)
   {
       s0 = eb_penangle * tan(pan1);
       s0 = atan(s0);
       if (pan1 > 0)
       {
           dpn1 = dpn1 * s0 / pan1;
           pan1 = s0;
       }
       s0 = eb_penangle * tan(pan2);
       s0 = atan(s0);
       if (pan2 > 0)
       {
           dpn2 = dpn2 * s0 / pan2;
           pan2 = s0;
       }
   }
 
   // get apex of penumbra cone
   pan1 = tan(pan1);
   if (pan1 != 0) dpn1 = dpn1 / pan1;
   else dpn1 = 1.2 * abs(eb_ubm);  // avoid a crash
   pan2 = tan(pan2);
   if (pan2 != 0) dpn2 = dpn2 / pan2;
   else dpn2 = dpn1;  // avoid a crash
 
   // get vector perpendicular to movement of shadow
   s0 = - dot(eb_ubm, eb_ube);
   ax1 = eb_ubm + s0 * eb_ube;
   eb_ubm = eb_ubm + (s0 - dpn1) * eb_ube;
   s0 = - dot(u2m, u2e);
   ax2 = u2m + s0 * u2e;
   u2m = u2m + (s0 - dpn2) * u2e;
   shmv = ax1 - ax2;
   ax2 = ax1 * ax2;
   shmv = shmv * ax2;
   shmv = vnorm(shmv);
 
   // now get the delta vectors
   eb_udm = u2m - eb_ubm;
   eb_lbe = eb_ube - pan1 * shmv;
   eb_ube = eb_ube + pan1 * shmv;
   eb_ude = u2e + pan2 * shmv;
   eb_lde = u2e - pan2 * shmv;
   eb_ube = vnorm(eb_ube);
   eb_lbe = vnorm(eb_lbe);
   eb_ude = vnorm(eb_ude);
   eb_lde = vnorm(eb_lde);
   eb_lde = eb_lde - eb_lbe;
   eb_ude = eb_ude - eb_ube;
 
   // scale the delta vectors
   dpn1 = eb_jdstop - eb_jdstart;
   if (dpn1 == 0) dpn1 = 1.0;
   else dpn1 = 1.0 / dpn1;
   eb_udm *= dpn1;
   eb_ude *= dpn1;
   eb_lde *= dpn1;
  }
 
 int EclSolar::GNSBound(bool firstc, bool north, double& lat, double& lng)
  {
   /* Get the geographic coordinates of the northern or southern boundaries
      at time t.
      INPUT:  firstc :true for first call
              north : true for southern boundary
              see also InitBound
      OUTPUT:
             lat, lng : latitude and longitude of penumbra boundary.
             If lat > 90 no northern boundary exists.
 
      RETURN: 1 if time within eclipse, 0 if end of eclipse
    */
   const double flat = 0.996633;  // flatting of the Earth
 
   double s0, s, r0, r2, dlt, t;
   Vec3 vrm, vre;
 
   if (eb_lunactive)  // only solar eclipses
   {
    lng = 0.0;
    lat = 100.0;
    return 0;
   };
 
   if (firstc)
   {
    InitBound();
    t = eb_jdstart;
    eb_lastjd = t;
   }
   else
   {
    t = eb_lastjd + double(eb_cstep) / (24.0*60.0);
    eb_lastjd = t;
   };
 
   if (t >= eb_jdstop)
   {
    lng = 0.0;
    lat = 100.0;
    return 0;
   };
 
   // get shadow vector at time t
   vrm = eb_ubm + (t - eb_jdstart) * eb_udm;
   if (north) vre = eb_ube + (t - eb_jdstart) * eb_ude;
   else vre = eb_lbe + (t - eb_jdstart) * eb_lde;
   vre = vnorm (vre);  // direction of penumbra boundary
 
   s0 = - dot(vrm, vre);   // distance Moon - fundamental plane
   r2 = dot (vrm,vrm);
   dlt = s0*s0 + 1.0 - r2;
   r0 = 1.0 - dlt;
 
   if (r0 > 0) r0 = sqrt (r0);
   else r0 = 0;      // distance center of Earth - shadow axis
 
   // calculate the coordinates if there is an intersecton
   if (r0 < 1.0)  // there should be an intersection
    {
     if (dlt > 0) dlt = sqrt(dlt);
     else dlt = 0;
     s = s0 - dlt;  // distance Moon - fundamental plane
     vrm = vrm + s * vre;
     vrm = vnorm(vrm);
     vrm[2] *= flat;    // vector to intersection
     vre = carpol(vrm);
     lng = vre[1] - lsidtim(t,0,0)*0.261799387799; // geographic coordinates
     if (lng > 2*M_PI) lng -= 2.0*M_PI;
     if (lng < 0.0) lng += 2.0*M_PI;
     lat = sqrt(vrm[0]*vrm[0] + vrm[1]*vrm[1])*0.993305615;
     lat = atan23(vrm[2],lat);
     lat /= degrad;
     lng /= degrad;
 
     if (lng < 0.0) lng += 360.0;
     if (lng > 360.0) lng -= 360.0;
    }
   else
    {
     lat = 100.0;
     lng = 0;
    };
 
   return 1;
  }
 
 //------------------ Sunrise / Sunset Boundaries ---------------------------
 
 void EclSolar::InRSBound()
  {
   /* Initialize the calculation for the sunrise and sunset boundaries
      of solar eclipses.
      The function EclStart must have been called first to enable InRSBound
      to get the right eclipse.
      The calculation is done in Earth radii.
 
      OUTPUT:
             eb_ubm : Moon base vector
             eb_ube : Shadod base vector
             eb_udm : Moon delta vector
             eb_ude : Shadow delta vector for
             eb_dpb : Base value for diameter of penumbra
             eb_dpd : delta value for diameter of penumbra
   */
 
   double pan;
   Vec3 u2m, u2e;
   Eclipse eclp;
 
   if (!eb_start_called) eclStart();
 
   // beginning of the eclipse
   eclp.penumd (eb_jdstart, eb_del_tdut, eb_ubm, eb_ube, eb_dpb, pan);
 
   // end of the eclipse
   eclp.penumd (eb_jdstop, eb_del_tdut, u2m, u2e, eb_dpd, pan);
 
   // get the delta vectors
   eb_udm = u2m - eb_ubm;
   eb_ude = u2e - eb_ube;
   eb_dpd = eb_dpd - eb_dpb;
 
   // scale the delta vectors
 
   pan = eb_jdstop - eb_jdstart;
   if (pan == 0) pan = 1.0;
   else pan = 1.0 / pan;
   eb_udm *= pan;
   eb_ude *= pan;
   eb_dpd *= pan;
  }
 
 int EclSolar::iscrs(double vrc0, double vrc1, double dpn,
                        double& vrx0, double& vrx1, double& vrx20, double& vrx21)
  {
   /* calculate intersection vectors of the penumbral cone with the
      Earth in the fundamental plane to find the locations of rise
      and set.
 
      INPUT : components of vectors vrc (pointing to the center of the
              penumbra), vre (unit vector perpendicular to the
              fundamental plane).
              dpn : half diameter of penumbra in Earth radii
 
      OUTPUT: components of the intersection vectors vrx and vrx2 if
              successful.
 
      RETURN: 1 if intersection successful, 0 otherwise.
   */
   int rtn;
   double a, b, c, f1, f2, f3, f4;
 
   rtn = 1;
   f1 = vrc0*vrc0;
 
   if (f1 < 1.0e-60) rtn = 0;
   else
    {
     f2 = 1.0 - dpn*dpn + f1 + vrc1*vrc1;
     f3 = f2 / (2.0*vrc0);
     f4 = vrc1 / vrc0;
     a = 1.0 + vrc1*vrc1 / f1;
     b = f2*vrc1 / f1;
     c = f2*f2 / (4.0*f1) - 1.0;
     if (fabs(a) < 1.0e-60) rtn = 0;
     else
      {
       vrx21 = -0.5 * b / a; ;
       vrx0 = vrx21*vrx21 - c / a;
       if (vrx0 < 0) rtn = 0;
       else
        {
         vrx0 = sqrt(vrx0);
         vrx1 = vrx21 + vrx0;
         vrx21 = vrx21 - vrx0;
         vrx0 = f3 + f4*vrx1;
         vrx20 = f3 + f4*vrx21;
         vrx1 = -vrx1;
         vrx21 = -vrx21;
        };
      };
    };
 
   return rtn;
  }
 
 int EclSolar::GRSBound(bool firstc, double& lat1, double& lng1, double& lat2, double& lng2)
  {
   /* Get the geographic coordinates of the boundaries for rise/set
      at time t.
 
      INPUT: firstc : true for first call
 
      OUTPUT:
             lat1, lng1; lat2, lng2  : latitude and longitude of first
                                       and second point ofboundary.
                                       If lat > 90 no respective point exists.
 
     RETURN: 0 if end of eclipse, 1 otherwise
   */
   const double flat = 0.996633;  // flatting of the Earth
 
   double s0, r0, dpn, t;
   Vec3 vrm, vre, vrc, vrx, vrx2;
   Mat3 m1, m2;
 
   if (eb_lunactive)  // only solar eclipses
   {
    lng1 = 0.0;
    lat1 = 100.0;
    lng2 = 0.0;
    lat2 = 100.0;
    eb_finished = true;
    return 0;
   };
 
   if (firstc)
   {
    InRSBound();
    t = eb_jdstart + 1.0/86400.0; // just add a second to be beyond the limit
    eb_lastjd = t;
    eb_finished = false;
   }
   else
   {
    t = eb_lastjd + double(eb_cstep) / (24.0*60.0);
    eb_lastjd = t;
   };
 
   if (t >= eb_jdstop)
   {
    if (eb_finished)
     {
      lng1 = 0.0;
      lat1 = 100.0;
      lng2 = 0.0;
      lat2 = 100.0;
      return 0;
     };
    t = eb_jdstop - 1.0/86400.0;  // just to go to the very end and then stop
    eb_lastjd = t;
    eb_finished = true;
   };
 
   // get position of penumbra and shadow cone
   vrm = eb_ubm + (t - eb_jdstart) * eb_udm;
   vre = eb_ube + (t - eb_jdstart) * eb_ude;
   vre = vnorm (vre);  // direction of penumbra boundary
   dpn = eb_dpb + (t - eb_jdstart) * eb_dpd;
   dpn *= 0.5;  // half cone diameter
   vrx = carpol(vre);
 
   m1 = zrot(vrx[1] + M_PI/2.0);
   m2 = xrot(M_PI/2.0 - vrx[2]);
   m1 = m2 * m1;   // rotation from equatorial into fundamental plane
   m2 = mxtrn(m1); // rotation from fundamental plane into equatorial
 
   // get vector to center of shadow in the fundamental plane
   s0 = - dot(vrm, vre);
   vrc = vrm + s0 * vre;
 
   r0 = abs(vrc);  // distance between center of Earth and center of shadow
   vrc = mxvct(m1, vrc);
 
   lng1 = 0;
   lat1 = 100.0;
   lng2 = 0;
   lat2 = 100.0;
   // check whether intersection of Earth and shadow cone are possible
   // in fundamental plane
   if ((r0 > fabs(1.0 - dpn)) && (r0 < fabs(1.0 + dpn)))
    {
     // now find the intersections
     if (iscrs(vrc[0],vrc[1], dpn, vrx[0],vrx[1], vrx2[0],vrx2[1])) lat1 = 0;
     else
      {
       if (iscrs(vrc[1],vrc[0], dpn, vrx[1],vrx[0], vrx2[1],vrx2[0])) lat1 = 0;
      };
    };
 
   // calculate the coordinates if there is an intersecton
   if (lat1 < 100.0)  // there should be an intersection
    {
     vrx[2] = 0;
     vrx = mxvct(m2, vrx);
     vrx = vnorm(vrx);
     vrx[2] *= flat;    // vector to intersection
     vre = carpol(vrx);
     lng1 = vre[1] - lsidtim(t,0,0)*0.261799387799; // geographic coordinates
 
     if (lng1 > M_PI) lng1 -= 2.0*M_PI;
     if (lng1 < (-M_PI)) lng1 += 2.0*M_PI;
     lat1 = sqrt(vrx[0]*vrx[0] + vrx[1]*vrx[1])*0.993305615;
     lat1 = atan23(vrx[2],lat1);
     lat1 /= degrad;
     lng1 /= degrad;
    };
   if (lat1 < 100.0)  // intersection #2
    {
     vrx2[2] = 0;
     vrx2 = mxvct(m2, vrx2);
     vrx2 = vnorm(vrx2);
     vrx2[2] *= flat;    // vector to intersection
     vre = carpol(vrx2);
     lng2 = vre[1] - lsidtim(t,0,0)*0.261799387799; // geographic coordinates
     if (lng2 > M_PI) lng2 -= 2.0*M_PI;
     if (lng2 < (-M_PI)) lng2 += 2.0*M_PI;
     lat2 = sqrt(vrx2[0]*vrx2[0] + vrx2[1]*vrx2[1])*0.993305615;
     lat2 = atan23(vrx2[2],lat2);
     lat2 /= degrad;
     lng2 /= degrad;
    };
 
   return 1;
  }
 
 /*------------------------- EclDetails ---------------------------------*/
 
 double EclSolar::DegFDms (double h)
  {
   /* convert degrees from d.fff -> d.mmsss where .mm are the minutes
      and sss are seconds (and fractions of seconds).
   */
   int mm, deg;
   double hh, t, sec;
 
   hh = fabs(h);
   dms (hh,deg,mm,sec);
   if (sec>=59.5)
    {
     mm++;
     sec = 0;
    };
   if (mm>59)
    {
     deg++;
     mm=0;
    };
   hh = double(deg);
   t = double(mm)/100.0;
   hh += t;
   t = sec/10000.0;
   hh += t;
   if (h < 0) hh = -hh;
 
   return hh;
  }
 
 int EclSolar::localStart(int j, double *spt, double *ept, int *spp,
                                int p, char *otxt)
  {
   /* get start and end times of the various phases of the eclipse
      j = index of the eclipse
      spt[i] = start time in MJD for phase i
      ept[i] = end time in MJD for phase i
      spp[i] = kind of phase i
       p = phase
 
       RETURN: the number of different phases of this eclipse.
 
      The step width will be 1 min
    */
   int nump, eflg, pcur, pold, maxp, i, npflg;
   double magecl;  // local magnitude of eclipse at jd
   double jd, step, jdf, d1, d2, elrise;
   double azim, elev, dist, phi, lamda;
   char dts[13];
   char outb[127];
   Vec3 gx;
   Eclipse eclp;
 
   nump = 0;
   maxp = 0;
   eflg = 0;  // end flag
   pold = 0;
   elev = 0;
   eb_lccnt = 0;
   eb_maxps = -1.0;
   eb_maxelv = -1.0;
   phi = eb_geolat * M_PI / 180.0;
   lamda = eb_geolong * M_PI / 180.0;
   jd = eb_eclmjd[j] - 0.5;  // start 12 hours before maximum
   jdf = jd + 1.5;  // emergency stop if something goes wrong with the loop
   step = 1.0/(24.0*60.0);  // stepwidth 1 minute
   eb_ltotb = jd;
   eb_ltote = jd - 1.0;
 
   do
    {
     if(p < 0)
      {
       pcur = eclp.lunar (jd, eb_del_tdut);
       gx = eclp.GetRMoon();
       magecl = 1.0;  // just set it 1. It's not needed for lunar eclipses.
       elrise = -9.89e-3;  // allow for refraction during rise/set
      }
     else
      {
       pcur = eclp.solar (jd, eb_del_tdut,d1, d2);
       gx = eclp.GetRSun();
       magecl = 0;
       elrise = -1.45e-2;  // allow for refraction during rise/set
      };
 
     // check whether body is visible from local position.
     if (pcur > 0)
      {
       AppPos (jd, eclp.GetEp2(), phi, lamda, eb_geoheight, 1, gx,
                                  azim, elev, dist);
       if ((p > 0) && (elev >= elrise))
        {
         magecl = getlocmag(jd, eclp.GetEp2(), phi, lamda, eb_geoheight,
                                eclp.GetRSun(),eclp.GetRMoon(), i);
         if (magecl > eb_maxps)
          {
           eb_maxps = magecl;
           eb_maxelv = elev;
           eb_jdmaxps = jd;
          }
        }
      }
 
     if ((eb_lccnt == 0) && (pcur != 0))
      {
       if ((elev >= elrise) && (magecl > 0))
        {
         eb_lcb1 = jd;
         eb_lccnt = 1;
        }
      }
     if (eb_lccnt == 1)
      {
       if ((elev < elrise) || (pcur == 0) || (magecl == 0))
        {
         eb_lce1 = jd;
         eb_lccnt = 2;
        }
      }
     if ((eb_lccnt == 2) && (pcur != 0))
      {
       if ((elev >= elrise) && (magecl > 0))
        {
         eb_lcb2 = jd;
         eb_lccnt = 3;
        }
      }
     if (eb_lccnt == 3)
      {
       if ((elev < elrise) || (pcur == 0) || (magecl == 0))
        {
         eb_lce2 = jd;
         eb_lccnt = 4;
        }
      }
 
     // now check the start and stop times for the phases
     if (pcur > pold)
      {
       if(nump < 4)
        {
         spt[nump] = jd;
         spp[nump] = pcur;
         nump++;
         maxp++;
         pold = pcur;
        }
      }
     else if (pcur < pold)
      {
       npflg = 1;
       if (nump > 1)
        {
         if (pcur > spp[nump-2]) npflg = 0;
        }
       if (npflg)
        {
         nump--;
         if (nump >= 0) ept[nump] = jd;
         if (nump > 1)
          {
           if (pcur < spp[nump-1])
            {
             nump--;
             ept[nump] = jd;
            }
          }
         if (nump <= 0) eflg = 1;
        }
       pold = pcur;
      };
 
     jd += step;
     if (jd > jdf) eflg = 1;
 
    } while (eflg != 1);
 
   //  put the respective info into textfile otxt
   if(maxp > 0)
    {
     for (i=0; i<maxp; i++)
      {
       if (p < 0)
        {
         switch (spp[i])
          {
           case 1: strcpy(outb,"penumbral   ");
                   break;
           case 2: strcpy(outb,"tot.penumb  ");
                   break;
           case 3: strcpy(outb,"partial     ");
                   break;
           case 4: strcpy(outb,"totality    ");
                   break;
          }
        }
       else
        {
         switch (spp[i])
          {
           case 1: strcpy(outb,"partial     ");
                   break;
           case 2: strcpy(outb,"n-centr.Ann ");
                   break;
           case 3: strcpy(outb,"n-centr.Tot ");
                   break;
           case 4: strcpy(outb,"annularity  ");
                   break;
           case 5: strcpy(outb,"totality    ");
                   break;
          }
        }
 
         strcat(otxt,"\n ");
         strcat(otxt, outb);
         strcat(otxt,"\tbegins ");
         dtmstr((spt[i]+eb_tzone/24.0),dts);
         dts[12] = '\0';
         strcat(otxt,dts);
         strcat(otxt, "\tends ");
         dtmstr((ept[i]+eb_tzone/24.0),dts);
         dts[12] = '\0';
         strcat(otxt,dts);
      }
    }
   if (maxp > 0)
    {
     if (eb_lccnt == 1) eb_lce1 = ept[0];
     if (eb_lccnt == 3) eb_lce2 = ept[0];
    }
 
   if (eb_maxps > 0.8)  // check for local central phase
    {
     jd = eb_jdmaxps - 16.0/(24.0*60.0);
     eb_ltote = jd + 32.0/(24.0*60.0);
     eflg = 0;
     do
      {
       jd += 1.0/86400.0;  // go in seconds steps
       eclp.solar (jd, eb_del_tdut,d1, d2);
       gx = eclp.GetRSun();
       AppPos (jd, eclp.GetEp2(), phi, lamda, eb_geoheight, 1, gx,
                                       azim, elev, dist);
       if (elev >= elrise)
        {
         magecl = getlocmag(jd, eclp.GetEp2(), phi, lamda, eb_geoheight,
                                eclp.GetRSun(),eclp.GetRMoon(), i);
         if (magecl > eb_maxps)
          {
           eb_maxelv = elev;
           eb_maxps = magecl;
           eb_jdmaxps = jd;
          }
         if (i > 0)
          {
           eb_ltotb = jd;
           eflg = 1;
          }
        }
       if (jd > eb_ltote) eflg = 1;
 
      } while (!eflg);
 
     if (jd < eb_ltote)
      {
       eflg = 0;
       do
        {
         jd += 1.0/86400.0;  // go in seconds steps
         eclp.solar (jd, eb_del_tdut,d1, d2);
         gx = eclp.GetRSun();
         AppPos (jd, eclp.GetEp2(), phi, lamda, eb_geoheight, 1, gx,
                                         azim, elev, dist);
         if (elev < elrise) eflg = 1;
         magecl = getlocmag(jd, eclp.GetEp2(), phi, lamda, eb_geoheight,
                                eclp.GetRSun(),eclp.GetRMoon(), i);
         if (magecl > eb_maxps)
          {
           eb_maxelv = elev;
           eb_maxps = magecl;
           eb_jdmaxps = jd;
          }
         if (i == 0) eflg = 1;
         if (jd > eb_ltote) eflg = 1;
 
        } while (!eflg);
       eb_ltote = jd;
      }
     else eb_ltote = eb_ltotb - 1.0;
    }
 
   return maxp;
  }
 
 
 void EclSolar::getLocalDetails(char *otxt)
  {
   /* get the details of the eclipse selected in eclbuf.select
      and place the output into otxt
   */
   int j, p, i, ecloutbn;
   int dd, mm, yy, deg, mnt;
   double sec, hh;
 
   int spp[4], nump;
   double spt[4], ept[4];
   double jd, jdf;
   char dts[13];
   char outb[127];
 
   if (!eb_start_called) eclStart();
   eb_local_called = true;
 
   j = eb_eclselect-1;
   p = eb_phase[j];
 
   ecloutbn = 3;
   sprintf(otxt,"+++ Timezone: %g +++  TT - UTC: %g (sec) +++ Year: %5i +++\n\n", eb_tzone, eb_del_tdut, eb_year);
     switch (p)
      {
       case 1: strcpy(outb,"\t\tPartial Eclipse of the Sun");
               break;
       case 2: strcpy(outb,"\t\tNon-Central Annular Eclipse of the Sun");
               break;
       case 3: strcpy(outb,"\t\tNon-Central Total Eclipse of the Sun");
               break;
       case 4: strcpy(outb,"\t\tAnnular Eclipse of the Sun");
               break;
       case 5: strcpy(outb, "\t\tTotal Eclipse of the Sun");
               break;
       case 6: strcpy(outb, "\t\tAnnular/Total Solar Eclipse");
               break;
 
       case -1:
       case -2: strcpy(outb, "\t\tPenumbral Eclipse of the Moon");
                break;
       case -3: strcpy(outb, "\t\tPartial eclipse of the Moon");
                break;
       case -4: strcpy(outb, "\t\tTotal eclipse of the Moon");
                break;
      };
 
     strcat(otxt,outb);
     sprintf(outb,"\n\nMaximum Eclipse at ");
     strcat(otxt,outb);
     dtmstr((eb_eclmjd[j]+eb_tzone/24.0),dts);
     dts[12] = '\0';
     strcat(otxt,dts);
     if (p < 4)
      {
       sprintf(outb,"   with magnitude:%5.2f",eb_magnitude[j]);
       strcat(otxt, outb);
      }
 
     strcat(otxt,"\n");
     nump = localStart(j, spt, ept, spp, p, otxt);
     if ((p < 4) || (nump < 1)) ecloutbn = 5;
 
   if (ecloutbn == 3)
    {
     // get start and stop dates for central phase
     jd = spt[nump-1];
     for (i=0; i<nump; i++)
     if ((spt[i] < jd) && (spp[i] > 3)) jd = spt[i]; // start of central phase
     caldat(jd, dd, mm, yy, hh);
     dms (hh,deg,mnt,sec);
     sec = 0;
     i = mnt / eb_cstep;
     mnt = i* int(eb_cstep);   // cut to proper time step
     hh = ddd (deg, mnt, sec);
     jdf = ept[nump-1];
     for (i=0; i<nump; i++)
      if ((ept[i] > jdf) && (spp[i] > 3)) jdf = ept[i]; // end of central phase
    }
 
   // local circumstances
       strcat(otxt, "\n\n\nLocal Circumstances for ");
       jd = eb_geolat;
       jdf = eb_geolong;
     sprintf(outb,"\nLat: %g   Long: %g   height: %g m\n\n",
                                jd, jdf, eb_geoheight);
     strcat(otxt,outb);
     if (p != 0)
      {
       if (eb_lccnt > 0)
        {
         sprintf(outb,"Eclipse visible from ");
         dtmstr((eb_lcb1+eb_tzone/24.0),dts);
         dts[12] = '\0';
         strcat(outb," ");
         strcat(outb,dts);
         strcat(outb," to ");
         dtmstr((eb_lce1+eb_tzone/24.0),dts);
         dts[12] = '\0';
         strcat(outb,dts);
         if (eb_lccnt > 2)  // this case almost never happens
          {
           strcat(otxt,outb);
           strcpy(outb,"\n\tand from ");
           dtmstr((eb_lcb2+eb_tzone/24.0),dts);
           dts[12] = '\0';
           strcat(outb," ");
           strcat(outb,dts);
           strcat(outb," to ");
           dtmstr((eb_lce2+eb_tzone/24.0),dts);
           dts[12] = '\0';
           strcat(outb,dts);
          }
        }
       else sprintf(outb,"Eclipse not visible");
       strcat(otxt,outb);
      }
 
    // local solar eclipse magnitude
     if ((p > 0) && (eb_lccnt > 0))
      {
       sprintf(outb,"\nMaximum Eclipse at ");
       strcat(otxt,outb);
       dtmstr((eb_jdmaxps+eb_tzone/24.0),dts);
       dts[12] = '\0';
       strcat(otxt,dts);
       sprintf(outb,"   with magnitude %6.3f", eb_maxps);
       strcat(otxt,outb);
       sprintf(outb,"   elev:%4.1f", 180.0*eb_maxelv/M_PI);
       strcat(otxt,outb);
       if (eb_ltotb <= eb_ltote)
        {      // local central eclipse
         if ((p % 2) == 0) strcpy(outb, "\nannularity from");
         else strcpy(outb, "\ntotality from");
         if ((p == 1) || (p == 6))
                    strcpy(outb, "\ntotality/annularity from");
         strcat(otxt,outb);
         caldat((eb_ltotb+eb_tzone/24.0), dd, mm, yy, hh);
         caldat((eb_ltote+eb_tzone/24.0), dd, mm, yy, jd);
         hh = DegFDms(hh);
         jd = DegFDms(jd);
         jdf = (eb_ltote - eb_ltotb) * 86400.0;
         sprintf(outb,"%8.4f  to%8.4f   del.t:%3.0f sec \n",hh,jd, jdf);
         strcat(otxt,outb);
        }
      }
 
     eb_maxelv /= degrad;
  }
 
 //---------Northern and Southern Umbra Boundaries ---------------------
 
 double EclSolar::navCourse (double lat1, double lng1, double lat2, double lng2)
 {
  // get course (in radians) from (lat1, lng1) to (lat2, lng2) over the Earth surface
  // the geographic coordinates are in decimal degrees
 
  double lt1, ln1, lt2, ln2, cd, an;
 
  lt1 = lat1 * degrad;
  ln1 = lng1 * degrad;
  lt2 = lat2 * degrad;
  ln2 = lng2 * degrad;
 
  cd = sin(lt1)*sin(lt2) + cos(lt1)*cos(lt2)*cos(ln2 - ln1);
  an = acos(cd);
  an = cos(lt1) * sin(an);
 
  if (an == 0) return 0;  // same spot. didn't move
 
  cd = (sin(lt2) - sin(lt1)*cd) / an;
  an = acos (cd);
 
  if (sin(ln2 - ln1) < 0) an = -an;
 
  return an;
 }
 
 void EclSolar::navNewPos (double d, double an, double lat1, double lng1, double &lat2, double &lng2)
 {
  /*
     starting from (lat1, lng1) along the great circle for d (radians) with course an (in radians)
     get the new position (lat2, lng2) (in decimal degrees) at the Earth surface
  */
 
  double cd, sd, lt1, ag;
 
  ag = an;
  if (ag > M_PI) ag -= 2*M_PI;
  if (ag < -M_PI) ag += 2*M_PI;
 
  cd = cos(d);
  lt1 = lat1 * degrad;
 
  sd = cd * sin(lt1) + sin(d) * cos(lt1) * cos(ag);
  lat2 = asin(sd);
 
  lng2 = cos(lt1) * cos(lat2);
 
  if (lng2 == 0)  // just in case to avoid a crash
  {
      lat2 = lat1;
      lng2 = lng1;
      return;
  }
 
  lng2 = (cd - sin(lt1) * sd) / lng2;
  lng2 = acos(lng2);
  lng2 /= degrad;
  if (ag > 0) lng2 = lng1 + lng2;
  else lng2 = lng1 -lng2;
  if(lng2 > 360.0) lng2 -= 360.0;
  if(lng2 < 0) lng2 += 360.0;
 
  lat2 /= degrad;
 
 }
 
 int EclSolar::centralBound(bool firstc, double& lat1, double& lng1, double& lat2, double& lng2)
 {
   /* Get the geographic coordinates of the northern or southern boundaries
      of the umbra at time t.
      INPUT:  firstc :true for first call
 
      OUTPUT:
             lat, lng : latitude and longitude of umbra boundary in decimal degrees.
             If lat > 90 no boundary exists.
 
      RETURN: current phase if time within eclipse, <=3 if no central eclipse
    */
 
   bool lastp;
   int k;
   double dpn1, t;
   double lt1, ln1, lt2, ln2, an;
   Eclipse eclp;
 
   if (!eb_start_called) eclStart();
 
   lng1 = 0.0;
   lat1 = 100.0;
   lng2 = 0.0;
   lat2 = 100.0;
 
   lastp = false;
 
   if (eb_lunactive) return 0;  // only solar eclipses
 
 
   if (firstc)
   {
    k = eclPltCentral(true, lt1, ln1);
   }
   else k = eclPltCentral(false, lt1, ln1);
   t = eb_lastjd;
 
   if (k <= 3) return k;  // no central eclipse
 
   k = eclPltCentral(false, lt2, ln2);  // next step
   eb_lastjd = t;  // go back to the original step
 
   if (k <= 3)  // try the last step instead at the end
   {
       eb_lastjd -= 2.0 * eb_cstep / (24.0*60.0);
       k = eclPltCentral(false, lt2, ln2);
       eb_lastjd = t;
       lastp = true;
   };
 
   if (k <= 3) return k;  // no central eclipse
 
   eclp.solar(t, eb_del_tdut, lat1, lng1);
   lat1 = 100.0;
   lng1 = 0;
 
   an = navCourse (lt1, ln1, lt2, ln2);  // direction of shadow along Earth surface
   an += 0.5*M_PI; // direction perpendicular to shadow movement (right boundary)
 
   eclp.duration(t, eb_del_tdut, dpn1);  // dpn1 is width of umbra in km
   dpn1 = (dpn1 / 111.1) * 0.0174533;  // radians of umbra width
   dpn1 /= 2.0;
   navNewPos(dpn1, an, lt1, ln1, lat1, lng1);
 
   an -= M_PI;  // find opposite boundary
 
   navNewPos(dpn1, an, lt1, ln1, lat2, lng2);
 
   if (lastp)  // we went the opposite way at the end
   {
       lt1 = lat2;
       ln1 = lng2;
       lat2 = lat1;
       lng2 = lng1;
       lat1 = lt1;
       lng1 = ln1;
       return 0;  // end of eclipse
   }
   else return k;
  }
 
 //-------------------- Shadow Cone -------------------------
 
 void EclSolar::getShadowCone(double mjd, bool umbra, int numpts, double* lat, double* lng)
 {
   /*  Get the geographic coordinates of the shadow cone at MJD-time mjd.
       if umbra is true the umbra cone will be returned
       if umbra is false the penumbra will be returned
 
      OUTPUT:
             lat and lng must be arrays of length numpts into which the numpts points will be placed
             if there is no (total) eclipse at the time, lat will be set 100.0, lng 0.
   */
 
   const double flat = 0.996633;  // flatting of the Earth
 
   int j, k1, k2, kmiss;
   double dpn1, pan1, s0, dlt, dta, ag;
   double s, r0, r2, dt1, dt2;
   Vec3 vrm, vre;
   Vec3 ubm, ube;
   Vec3 ax1, ax2;
   Mat3 mx1, mx2;
   Eclipse eclp;
 
   if (numpts < 2) return;
 
   for (j=0; j<numpts; j++)  // just in case you got to return empty-handed
   {
       lat[j] = 100.0;
       lng[j] = 0;
   }
 
   if (!eb_start_called) eclStart();
   if (eb_lunactive) return;  // only for solar eclipses
 
   if (umbra && (eb_phase[eb_eclselect-1] < 1)) return;
 
   // get the shadow details
   if(umbra)  eclp.umbra (mjd, eb_del_tdut, ubm, ube, dpn1, pan1);
   else eclp.penumd (mjd, eb_del_tdut, ubm, ube, dpn1, pan1);
 
   dpn1 *= 0.5;
 
   if (!umbra)
   {
       if (eb_penamode == 0)
       {
         dpn1 *= eb_penangle;
         pan1 *= eb_penangle;
       }
 
       if (eb_penamode > 0)
       {
           s0 = eb_penangle * tan(pan1);
           s0 = atan(s0);
           if (pan1 > 0)
           {
               dpn1 = dpn1 * s0 / pan1;
               pan1 = s0;
           }
       }
   };
 
   // get apex of umbra/penumbra cone
   pan1 = tan(pan1);
   if (pan1 < 0.0000174533) return;  // if cone is smaller that 0.001°
   dpn1 = dpn1 / pan1;
 
   s0 = - dot(ubm, ube);
   ubm = ubm + (s0 - dpn1) * ube;
 
   // get any vector perpendicular to the shadow
   ax1[0] = 0;
   ax1[1] = 0;
   ax1[2] = 1.0;
   ax2 = ax1 * ube;
   ax1 = vnorm(ax2) * pan1;
 
   ax2 = carpol(ube);
   mx1 = zrot(ax2[1]);
   mx2 = yrot(ax2[2]) * mx1;  // transform to a system where x points into the direction of the shadow
   mx1 = mxtrn(mx1);  // to get back to equatorial system after rotation
 
   ax2 = mxvct(mx2,ax1);  // vector which we will rotate numpts times
 
   // now loop for numpts points
   dta = 2.0*M_PI / double(numpts);
 
   for (j=0; j<numpts; j++)
   {
       ag = double(j) * dta;  // rotation angle of the cone vector
       mx2  = xrot(ag);
       ax1 = mxvct(mx2,ax2);
       ax1 = mxvct(mx1, ax1);
 
       vre = ube + ax1;
       vre = vnorm(vre);  // direction in which to find an intersection
       vrm[0] = ubm[0];
       vrm[1] = ubm[1];
       vrm[2] = ubm[2];
 
       s0 = - dot(vrm, vre); // distance Apex - fundamental plane
       r2 = dot (vrm,vrm);
       dlt = s0*s0 + 1.0 - r2;
       r0 = 1.0 - dlt;
 
       if (r0 > 0) r0 = sqrt (r0);
       else r0 = 0;   // distance center of Earth - shadow axis
 
       // calculate the coordinates if there is an intersecton
       if (r0 < 1.0)  // there should be an intersection
       {
        if (dlt > 0) dlt = sqrt(dlt);
        else dlt = 0;
        s = s0 - dlt;  // distance Apex - fundamental plane
        vrm = vrm + s * vre;
        vrm = vnorm(vrm);
        vrm[2] *= flat;    // vector to intersection
        vre = carpol(vrm);
        lng[j] = vre[1] - lsidtim(mjd,0,0)*0.261799387799; // geographic coordinates
        if (lng[j] > 2*M_PI) lng[j] -= 2.0*M_PI;
        if (lng[j] < 0.0) lng[j] += 2.0*M_PI;
        lat[j] = sqrt(vrm[0]*vrm[0] + vrm[1]*vrm[1])*0.993305615;
        lat[j] = atan23(vrm[2],lat[j]);
        lat[j] /= degrad;
        lng[j] /= degrad;
 
        if (lng[j] < 0.0) lng[j] += 360.0;
        if (lng[j] > 360.0) lng[j] -= 360.0;
       }
       else  // no intersection.
       {
           lat[j] = 100.0;
           lng[j] = 0;
       };
   }
 
   k1 = -1;
   k2 = -1;
   kmiss = 0;
   for (j=0; j<numpts; j++)  // check for missing points
   {
       if (lat[j] < 100.0)
       {
           if (k1 < 0) k1 = j;  // first valid point
           k2 = j;              // last valid point
       }
       else kmiss++;
   }
 
   if ((kmiss < 2) || (kmiss >= (numpts -1))) return;  // cone completely on Earth surface or not at all
 
   dt1 = double(k1) * dta;
   dt2 = double(k2) * dta;
   k1--;
   k2++;
   if (k1 < 0) k1 = numpts - 1;  // wrap around
   if (k2 >= (numpts-1)) k2 = 0;
   dta = 2.0*M_PI / double(numpts*20);
 
   for (j=1; j<20; j++) // go in smaller steps to get closer to the borderline
   {
       ag = dt1 - double(j) * dta;  // rotation angle of the cone vector
       mx2  = xrot(ag);
       ax1 = mxvct(mx2,ax2);
       ax1 = mxvct(mx1, ax1);
 
       vre = ube + ax1;
       vre = vnorm(vre);  // direction in which to find an intersection
       vrm[0] = ubm[0];
       vrm[1] = ubm[1];
       vrm[2] = ubm[2];
 
       s0 = - dot(vrm, vre); // distance Apex - fundamental plane
       r2 = dot (vrm,vrm);
       dlt = s0*s0 + 1.0 - r2;
       r0 = 1.0 - dlt;
 
       if (r0 > 0) r0 = sqrt (r0);
       else r0 = 0;   // distance center of Earth - shadow axis
 
       // calculate the coordinates if there is an intersecton
       if (r0 < 1.0)  // there should be an intersection
       {
        if (dlt > 0) dlt = sqrt(dlt);
        else dlt = 0;
        s = s0 - dlt;  // distance Apex - fundamental plane
        vrm = vrm + s * vre;
        vrm = vnorm(vrm);
        vrm[2] *= flat;    // vector to intersection
        vre = carpol(vrm);
        lng[k1] = vre[1] - lsidtim(mjd,0,0)*0.261799387799; // geographic coordinates
        if (lng[k1] > 2*M_PI) lng[k1] -= 2.0*M_PI;
        if (lng[k1] < 0.0) lng[k1] += 2.0*M_PI;
        lat[k1] = sqrt(vrm[0]*vrm[0] + vrm[1]*vrm[1])*0.993305615;
        lat[k1] = atan23(vrm[2],lat[k1]);
        lat[k1] /= degrad;
        lng[k1] /= degrad;
 
        if (lng[k1] < 0.0) lng[k1] += 360.0;
        if (lng[k1] > 360.0) lng[k1] -= 360.0;
       }
       else break;
   }
 
   for (j=1; j<20; j++) // go in smaller steps to get closer to the borderline
   {
       ag = dt2 + double(j) * dta;  // rotation angle of the cone vector
       mx2  = xrot(ag);
       ax1 = mxvct(mx2,ax2);
       ax1 = mxvct(mx1, ax1);
 
       vre = ube + ax1;
       vre = vnorm(vre);  // direction in which to find an intersection
       vrm[0] = ubm[0];
       vrm[1] = ubm[1];
       vrm[2] = ubm[2];
 
       s0 = - dot(vrm, vre); // distance Apex - fundamental plane
       r2 = dot (vrm,vrm);
       dlt = s0*s0 + 1.0 - r2;
       r0 = 1.0 - dlt;
 
       if (r0 > 0) r0 = sqrt (r0);
       else r0 = 0;   // distance center of Earth - shadow axis
 
       // calculate the coordinates if there is an intersecton
       if (r0 < 1.0)  // there should be an intersection
       {
        if (dlt > 0) dlt = sqrt(dlt);
        else dlt = 0;
        s = s0 - dlt;  // distance Apex - fundamental plane
        vrm = vrm + s * vre;
        vrm = vnorm(vrm);
        vrm[2] *= flat;    // vector to intersection
        vre = carpol(vrm);
        lng[k2] = vre[1] - lsidtim(mjd,0,0)*0.261799387799; // geographic coordinates
        if (lng[k2] > 2*M_PI) lng[k2] -= 2.0*M_PI;
        if (lng[k2] < 0.0) lng[k2] += 2.0*M_PI;
        lat[k2] = sqrt(vrm[0]*vrm[0] + vrm[1]*vrm[1])*0.993305615;
        lat[k2] = atan23(vrm[2],lat[k2]);
        lat[k2] /= degrad;
        lng[k2] /= degrad;
 
        if (lng[k2] < 0.0) lng[k2] += 360.0;
        if (lng[k2] > 360.0) lng[k2] -= 360.0;
       }
       else break;
   }
 
 }