icuSources/i18n/astro.cpp

   1 /************************************************************************
   2  * Copyright (C) 1996-2006, International Business Machines Corporation *
   3  * and others. All Rights Reserved.                                     *
   4  ************************************************************************
   5  *  2003-nov-07   srl       Port from Java
   6  */
   7
   8 #include "astro.h"
   9
  10 #if !UCONFIG_NO_FORMATTING
  11
  12 #include "unicode/calendar.h"
  13 #include "math.h"
  14 #include <float.h>
  15 #include "unicode/putil.h"
  16 #include "uhash.h"
  17 #include "umutex.h"
  18 #include "ucln_in.h"
  19 #include "putilimp.h"
  20 #include <stdio.h>  // for toString()
  21
  22 #ifdef U_DEBUG_ASTRO
  23 # include "uresimp.h" // for debugging
  24
  25 static void debug_astro_loc(const char *f, int32_t l)
  26 {
  27   fprintf(stderr, "%s:%d: ", f, l);
  28 }
  29
  30 static void debug_astro_msg(const char *pat, ...)
  31 {
  32   va_list ap;
  33   va_start(ap, pat);
  34   vfprintf(stderr, pat, ap);
  35   fflush(stderr);
  36 }
  37 #include "unicode/datefmt.h"
  38 #include "unicode/ustring.h"
  39 static const char * debug_astro_date(UDate d) {
  40   static char gStrBuf[1024];
  41   static DateFormat *df = NULL;
  42   if(df == NULL) {
  43     df = DateFormat::createDateTimeInstance(DateFormat::MEDIUM, DateFormat::MEDIUM, Locale::getUS());
  44     df->adoptTimeZone(TimeZone::getGMT()->clone());
  45   }
  46   UnicodeString str;
  47   df->format(d,str);
  48   u_austrncpy(gStrBuf,str.getTerminatedBuffer(),sizeof(gStrBuf)-1);
  49   return gStrBuf;
  50 }
  51
  52 // must use double parens, i.e.:  U_DEBUG_ASTRO_MSG(("four is: %d",4));
  53 #define U_DEBUG_ASTRO_MSG(x) {debug_astro_loc(__FILE__,__LINE__);debug_astro_msg x;}
  54 #else
  55 #define U_DEBUG_ASTRO_MSG(x)
  56 #endif
  57
  58 static inline UBool isINVALID(double d) {
  59   return(uprv_isNaN(d));
  60 }
  61
  62 static UMTX ccLock = NULL;
  63
  64 U_CDECL_BEGIN
  65 static UBool calendar_astro_cleanup(void) {
  66   umtx_destroy(&ccLock);
  67   return TRUE;
  68 }
  69 U_CDECL_END
  70
  71 U_NAMESPACE_BEGIN
  72
  73 /**
  74  * The number of standard hours in one sidereal day.
  75  * Approximately 24.93.
  76  * @internal
  77  * @deprecated ICU 2.4. This class may be removed or modified.
  78  */
  79 #define SIDEREAL_DAY (23.93446960027)
  80
  81 /**
  82  * The number of sidereal hours in one mean solar day.
  83  * Approximately 24.07.
  84  * @internal
  85  * @deprecated ICU 2.4. This class may be removed or modified.
  86  */
  87 #define SOLAR_DAY  (24.065709816)
  88
  89 /**
  90  * The average number of solar days from one new moon to the next.  This is the time
  91  * it takes for the moon to return the same ecliptic longitude as the sun.
  92  * It is longer than the sidereal month because the sun's longitude increases
  93  * during the year due to the revolution of the earth around the sun.
  94  * Approximately 29.53.
  95  *
  96  * @see #SIDEREAL_MONTH
  97  * @internal
  98  * @deprecated ICU 2.4. This class may be removed or modified.
  99  */
 100 const double CalendarAstronomer::SYNODIC_MONTH  = 29.530588853;
 101
 102 /**
 103  * The average number of days it takes
 104  * for the moon to return to the same ecliptic longitude relative to the
 105  * stellar background.  This is referred to as the sidereal month.
 106  * It is shorter than the synodic month due to
 107  * the revolution of the earth around the sun.
 108  * Approximately 27.32.
 109  *
 110  * @see #SYNODIC_MONTH
 111  * @internal
 112  * @deprecated ICU 2.4. This class may be removed or modified.
 113  */
 114 #define SIDEREAL_MONTH  27.32166
 115
 116 /**
 117  * The average number number of days between successive vernal equinoxes.
 118  * Due to the precession of the earth's
 119  * axis, this is not precisely the same as the sidereal year.
 120  * Approximately 365.24
 121  *
 122  * @see #SIDEREAL_YEAR
 123  * @internal
 124  * @deprecated ICU 2.4. This class may be removed or modified.
 125  */
 126 #define TROPICAL_YEAR  365.242191
 127
 128 /**
 129  * The average number of days it takes
 130  * for the sun to return to the same position against the fixed stellar
 131  * background.  This is the duration of one orbit of the earth about the sun
 132  * as it would appear to an outside observer.
 133  * Due to the precession of the earth's
 134  * axis, this is not precisely the same as the tropical year.
 135  * Approximately 365.25.
 136  *
 137  * @see #TROPICAL_YEAR
 138  * @internal
 139  * @deprecated ICU 2.4. This class may be removed or modified.
 140  */
 141 #define SIDEREAL_YEAR  365.25636
 142
 143 //-------------------------------------------------------------------------
 144 // Time-related constants
 145 //-------------------------------------------------------------------------
 146
 147 /**
 148  * The number of milliseconds in one second.
 149  * @internal
 150  * @deprecated ICU 2.4. This class may be removed or modified.
 151  */
 152 #define SECOND_MS  U_MILLIS_PER_SECOND
 153
 154 /**
 155  * The number of milliseconds in one minute.
 156  * @internal
 157  * @deprecated ICU 2.4. This class may be removed or modified.
 158  */
 159 #define MINUTE_MS  U_MILLIS_PER_MINUTE
 160
 161 /**
 162  * The number of milliseconds in one hour.
 163  * @internal
 164  * @deprecated ICU 2.4. This class may be removed or modified.
 165  */
 166 #define HOUR_MS   U_MILLIS_PER_HOUR
 167
 168 /**
 169  * The number of milliseconds in one day.
 170  * @internal
 171  * @deprecated ICU 2.4. This class may be removed or modified.
 172  */
 173 #define DAY_MS U_MILLIS_PER_DAY
 174
 175 /**
 176  * The start of the julian day numbering scheme used by astronomers, which
 177  * is 1/1/4713 BC (Julian), 12:00 GMT.  This is given as the number of milliseconds
 178  * since 1/1/1970 AD (Gregorian), a negative number.
 179  * Note that julian day numbers and
 180  * the Julian calendar are <em>not</em> the same thing.  Also note that
 181  * julian days start at <em>noon</em>, not midnight.
 182  * @internal
 183  * @deprecated ICU 2.4. This class may be removed or modified.
 184  */
 185 #define JULIAN_EPOCH_MS  -210866760000000.0
 186
 187
 188 /**
 189  * Milliseconds value for 0.0 January 2000 AD.
 190  */
 191 #define EPOCH_2000_MS  946598400000.0
 192
 193 //-------------------------------------------------------------------------
 194 // Assorted private data used for conversions
 195 //-------------------------------------------------------------------------
 196
 197 // My own copies of these so compilers are more likely to optimize them away
 198 const double CalendarAstronomer::PI = 3.14159265358979323846;
 199
 200 #define CalendarAstronomer_PI2  (CalendarAstronomer::PI*2.0)
 201 #define RAD_HOUR  ( 12 / CalendarAstronomer::PI )     // radians -> hours
 202 #define DEG_RAD ( CalendarAstronomer::PI / 180 )      // degrees -> radians
 203 #define RAD_DEG  ( 180 / CalendarAstronomer::PI )     // radians -> degrees
 204
 205 //-------------------------------------------------------------------------
 206 // Constructors
 207 //-------------------------------------------------------------------------
 208
 209 /**
 210  * Construct a new <code>CalendarAstronomer</code> object that is initialized to
 211  * the current date and time.
 212  * @internal
 213  * @deprecated ICU 2.4. This class may be removed or modified.
 214  */
 215 CalendarAstronomer::CalendarAstronomer():
 216   fTime(Calendar::getNow()), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
 217   clearCache();
 218 }
 219
 220 /**
 221  * Construct a new <code>CalendarAstronomer</code> object that is initialized to
 222  * the specified date and time.
 223  * @internal
 224  * @deprecated ICU 2.4. This class may be removed or modified.
 225  */
 226 CalendarAstronomer::CalendarAstronomer(UDate d): fTime(d), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
 227   clearCache();
 228 }
 229
 230 /**
 231  * Construct a new <code>CalendarAstronomer</code> object with the given
 232  * latitude and longitude.  The object's time is set to the current
 233  * date and time.
 234  * <p>
 235  * @param longitude The desired longitude, in <em>degrees</em> east of
 236  *                  the Greenwich meridian.
 237  *
 238  * @param latitude  The desired latitude, in <em>degrees</em>.  Positive
 239  *                  values signify North, negative South.
 240  *
 241  * @see java.util.Date#getTime()
 242  * @internal
 243  * @deprecated ICU 2.4. This class may be removed or modified.
 244  */
 245 CalendarAstronomer::CalendarAstronomer(double longitude, double latitude) :
 246   fTime(Calendar::getNow()), moonPosition(0,0), moonPositionSet(FALSE) {
 247   fLongitude = normPI(longitude * (double)DEG_RAD);
 248   fLatitude  = normPI(latitude  * (double)DEG_RAD);
 249   fGmtOffset = (double)(fLongitude * 24. * (double)HOUR_MS / (double)CalendarAstronomer_PI2);
 250   clearCache();
 251 }
 252
 253 CalendarAstronomer::~CalendarAstronomer()
 254 {
 255 }
 256
 257 //-------------------------------------------------------------------------
 258 // Time and date getters and setters
 259 //-------------------------------------------------------------------------
 260
 261 /**
 262  * Set the current date and time of this <code>CalendarAstronomer</code> object.  All
 263  * astronomical calculations are performed based on this time setting.
 264  *
 265  * @param aTime the date and time, expressed as the number of milliseconds since
 266  *              1/1/1970 0:00 GMT (Gregorian).
 267  *
 268  * @see #setDate
 269  * @see #getTime
 270  * @internal
 271  * @deprecated ICU 2.4. This class may be removed or modified.
 272  */
 273 void CalendarAstronomer::setTime(UDate aTime) {
 274   fTime = aTime;
 275   U_DEBUG_ASTRO_MSG(("setTime(%.1lf, %sL)\n", aTime, debug_astro_date(aTime+fGmtOffset)));
 276   clearCache();
 277 }
 278
 279 /**
 280  * Set the current date and time of this <code>CalendarAstronomer</code> object.  All
 281  * astronomical calculations are performed based on this time setting.
 282  *
 283  * @param jdn   the desired time, expressed as a "julian day number",
 284  *              which is the number of elapsed days since
 285  *              1/1/4713 BC (Julian), 12:00 GMT.  Note that julian day
 286  *              numbers start at <em>noon</em>.  To get the jdn for
 287  *              the corresponding midnight, subtract 0.5.
 288  *
 289  * @see #getJulianDay
 290  * @see #JULIAN_EPOCH_MS
 291  * @internal
 292  * @deprecated ICU 2.4. This class may be removed or modified.
 293  */
 294 void CalendarAstronomer::setJulianDay(double jdn) {
 295   fTime = (double)(jdn * DAY_MS) + JULIAN_EPOCH_MS;
 296   clearCache();
 297   julianDay = jdn;
 298 }
 299
 300 /**
 301  * Get the current time of this <code>CalendarAstronomer</code> object,
 302  * represented as the number of milliseconds since
 303  * 1/1/1970 AD 0:00 GMT (Gregorian).
 304  *
 305  * @see #setTime
 306  * @see #getDate
 307  * @internal
 308  * @deprecated ICU 2.4. This class may be removed or modified.
 309  */
 310 UDate CalendarAstronomer::getTime() {
 311   return fTime;
 312 }
 313
 314 /**
 315  * Get the current time of this <code>CalendarAstronomer</code> object,
 316  * expressed as a "julian day number", which is the number of elapsed
 317  * days since 1/1/4713 BC (Julian), 12:00 GMT.
 318  *
 319  * @see #setJulianDay
 320  * @see #JULIAN_EPOCH_MS
 321  * @internal
 322  * @deprecated ICU 2.4. This class may be removed or modified.
 323  */
 324 double CalendarAstronomer::getJulianDay() {
 325   if (isINVALID(julianDay)) {
 326     julianDay = (fTime - (double)JULIAN_EPOCH_MS) / (double)DAY_MS;
 327   }
 328   return julianDay;
 329 }
 330
 331 /**
 332  * Return this object's time expressed in julian centuries:
 333  * the number of centuries after 1/1/1900 AD, 12:00 GMT
 334  *
 335  * @see #getJulianDay
 336  * @internal
 337  * @deprecated ICU 2.4. This class may be removed or modified.
 338  */
 339 double CalendarAstronomer::getJulianCentury() {
 340   if (isINVALID(julianCentury)) {
 341     julianCentury = (getJulianDay() - 2415020.0) / 36525.0;
 342   }
 343   return julianCentury;
 344 }
 345
 346 /**
 347  * Returns the current Greenwich sidereal time, measured in hours
 348  * @internal
 349  * @deprecated ICU 2.4. This class may be removed or modified.
 350  */
 351 double CalendarAstronomer::getGreenwichSidereal() {
 352   if (isINVALID(siderealTime)) {
 353     // See page 86 of "Practial Astronomy with your Calculator",
 354     // by Peter Duffet-Smith, for details on the algorithm.
 355
 356     double UT = normalize(fTime/(double)HOUR_MS, 24.);
 357
 358     siderealTime = normalize(getSiderealOffset() + UT*1.002737909, 24.);
 359   }
 360   return siderealTime;
 361 }
 362
 363 double CalendarAstronomer::getSiderealOffset() {
 364   if (isINVALID(siderealT0)) {
 365     double JD  = uprv_floor(getJulianDay() - 0.5) + 0.5;
 366     double S   = JD - 2451545.0;
 367     double T   = S / 36525.0;
 368     siderealT0 = normalize(6.697374558 + 2400.051336*T + 0.000025862*T*T, 24);
 369   }
 370   return siderealT0;
 371 }
 372
 373 /**
 374  * Returns the current local sidereal time, measured in hours
 375  * @internal
 376  * @deprecated ICU 2.4. This class may be removed or modified.
 377  */
 378 double CalendarAstronomer::getLocalSidereal() {
 379   return normalize(getGreenwichSidereal() + (fGmtOffset/(double)HOUR_MS), 24.);
 380 }
 381
 382 /**
 383  * Converts local sidereal time to Universal Time.
 384  *
 385  * @param lst   The Local Sidereal Time, in hours since sidereal midnight
 386  *              on this object's current date.
 387  *
 388  * @return      The corresponding Universal Time, in milliseconds since
 389  *              1 Jan 1970, GMT.
 390  */
 391 double CalendarAstronomer::lstToUT(double lst) {
 392   // Convert to local mean time
 393   double lt = normalize((lst - getSiderealOffset()) * 0.9972695663, 24);
 394
 395   // Then find local midnight on this day
 396   double base = (DAY_MS * Math::floorDivide(fTime + fGmtOffset,(double)DAY_MS)) - fGmtOffset;
 397
 398   //out("    lt  =" + lt + " hours");
 399   //out("    base=" + new Date(base));
 400
 401   return base + (long)(lt * HOUR_MS);
 402 }
 403
 404
 405 //-------------------------------------------------------------------------
 406 // Coordinate transformations, all based on the current time of this object
 407 //-------------------------------------------------------------------------
 408
 409 /**
 410  * Convert from ecliptic to equatorial coordinates.
 411  *
 412  * @param ecliptic  A point in the sky in ecliptic coordinates.
 413  * @return          The corresponding point in equatorial coordinates.
 414  * @internal
 415  * @deprecated ICU 2.4. This class may be removed or modified.
 416  */
 417 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, const CalendarAstronomer::Ecliptic& ecliptic)
 418 {
 419   return eclipticToEquatorial(result, ecliptic.longitude, ecliptic.latitude);
 420 }
 421
 422 /**
 423  * Convert from ecliptic to equatorial coordinates.
 424  *
 425  * @param eclipLong     The ecliptic longitude
 426  * @param eclipLat      The ecliptic latitude
 427  *
 428  * @return              The corresponding point in equatorial coordinates.
 429  * @internal
 430  * @deprecated ICU 2.4. This class may be removed or modified.
 431  */
 432 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat)
 433 {
 434   // See page 42 of "Practial Astronomy with your Calculator",
 435   // by Peter Duffet-Smith, for details on the algorithm.
 436
 437   double obliq = eclipticObliquity();
 438   double sinE = ::sin(obliq);
 439   double cosE = cos(obliq);
 440
 441   double sinL = ::sin(eclipLong);
 442   double cosL = cos(eclipLong);
 443
 444   double sinB = ::sin(eclipLat);
 445   double cosB = cos(eclipLat);
 446   double tanB = tan(eclipLat);
 447
 448   result.set(atan2(sinL*cosE - tanB*sinE, cosL),
 449              asin(sinB*cosE + cosB*sinE*sinL) );
 450   return result;
 451 }
 452
 453 /**
 454  * Convert from ecliptic longitude to equatorial coordinates.
 455  *
 456  * @param eclipLong     The ecliptic longitude
 457  *
 458  * @return              The corresponding point in equatorial coordinates.
 459  * @internal
 460  * @deprecated ICU 2.4. This class may be removed or modified.
 461  */
 462 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong)
 463 {
 464   return eclipticToEquatorial(result, eclipLong, 0);  // TODO: optimize
 465 }
 466
 467 /**
 468  * @internal
 469  * @deprecated ICU 2.4. This class may be removed or modified.
 470  */
 471 CalendarAstronomer::Horizon& CalendarAstronomer::eclipticToHorizon(CalendarAstronomer::Horizon& result, double eclipLong)
 472 {
 473   Equatorial equatorial;
 474   eclipticToEquatorial(equatorial, eclipLong);
 475
 476   double H = getLocalSidereal()*CalendarAstronomer::PI/12 - equatorial.ascension;     // Hour-angle
 477
 478   double sinH = ::sin(H);
 479   double cosH = cos(H);
 480   double sinD = ::sin(equatorial.declination);
 481   double cosD = cos(equatorial.declination);
 482   double sinL = ::sin(fLatitude);
 483   double cosL = cos(fLatitude);
 484
 485   double altitude = asin(sinD*sinL + cosD*cosL*cosH);
 486   double azimuth  = atan2(-cosD*cosL*sinH, sinD - sinL * ::sin(altitude));
 487
 488   result.set(azimuth, altitude);
 489   return result;
 490 }
 491
 492
 493 //-------------------------------------------------------------------------
 494 // The Sun
 495 //-------------------------------------------------------------------------
 496
 497 //
 498 // Parameters of the Sun's orbit as of the epoch Jan 0.0 1990
 499 // Angles are in radians (after multiplying by CalendarAstronomer::PI/180)
 500 //
 501 #define JD_EPOCH  2447891.5 // Julian day of epoch
 502
 503 #define SUN_ETA_G    (279.403303 * CalendarAstronomer::PI/180) // Ecliptic longitude at epoch
 504 #define SUN_OMEGA_G  (282.768422 * CalendarAstronomer::PI/180) // Ecliptic longitude of perigee
 505 #define SUN_E         0.016713          // Eccentricity of orbit
 506 //double sunR0        1.495585e8        // Semi-major axis in KM
 507 //double sunTheta0    (0.533128 * CalendarAstronomer::PI/180) // Angular diameter at R0
 508
 509 // The following three methods, which compute the sun parameters
 510 // given above for an arbitrary epoch (whatever time the object is
 511 // set to), make only a small difference as compared to using the
 512 // above constants.  E.g., Sunset times might differ by ~12
 513 // seconds.  Furthermore, the eta-g computation is befuddled by
 514 // Duffet-Smith's incorrect coefficients (p.86).  I've corrected
 515 // the first-order coefficient but the others may be off too - no
 516 // way of knowing without consulting another source.
 517
 518 //  /**
 519 //   * Return the sun's ecliptic longitude at perigee for the current time.
 520 //   * See Duffett-Smith, p. 86.
 521 //   * @return radians
 522 //   */
 523 //  private double getSunOmegaG() {
 524 //      double T = getJulianCentury();
 525 //      return (281.2208444 + (1.719175 + 0.000452778*T)*T) * DEG_RAD;
 526 //  }
 527
 528 //  /**
 529 //   * Return the sun's ecliptic longitude for the current time.
 530 //   * See Duffett-Smith, p. 86.
 531 //   * @return radians
 532 //   */
 533 //  private double getSunEtaG() {
 534 //      double T = getJulianCentury();
 535 //      //return (279.6966778 + (36000.76892 + 0.0003025*T)*T) * DEG_RAD;
 536 //      //
 537 //      // The above line is from Duffett-Smith, and yields manifestly wrong
 538 //      // results.  The below constant is derived empirically to match the
 539 //      // constant he gives for the 1990 EPOCH.
 540 //      //
 541 //      return (279.6966778 + (-0.3262541582718024 + 0.0003025*T)*T) * DEG_RAD;
 542 //  }
 543
 544 //  /**
 545 //   * Return the sun's eccentricity of orbit for the current time.
 546 //   * See Duffett-Smith, p. 86.
 547 //   * @return double
 548 //   */
 549 //  private double getSunE() {
 550 //      double T = getJulianCentury();
 551 //      return 0.01675104 - (0.0000418 + 0.000000126*T)*T;
 552 //  }
 553
 554 /**
 555  * The longitude of the sun at the time specified by this object.
 556  * The longitude is measured in radians along the ecliptic
 557  * from the "first point of Aries," the point at which the ecliptic
 558  * crosses the earth's equatorial plane at the vernal equinox.
 559  * <p>
 560  * Currently, this method uses an approximation of the two-body Kepler's
 561  * equation for the earth and the sun.  It does not take into account the
 562  * perturbations caused by the other planets, the moon, etc.
 563  * @internal
 564  * @deprecated ICU 2.4. This class may be removed or modified.
 565  */
 566 double CalendarAstronomer::getSunLongitude()
 567 {
 568   // See page 86 of "Practial Astronomy with your Calculator",
 569   // by Peter Duffet-Smith, for details on the algorithm.
 570
 571   if (isINVALID(sunLongitude)) {
 572     getSunLongitude(getJulianDay(), sunLongitude, meanAnomalySun);
 573   }
 574   return sunLongitude;
 575 }
 576
 577 /**
 578  * TODO Make this public when the entire class is package-private.
 579  */
 580 /*public*/ void CalendarAstronomer::getSunLongitude(double jDay, double &longitude, double &meanAnomaly)
 581 {
 582   // See page 86 of "Practial Astronomy with your Calculator",
 583   // by Peter Duffet-Smith, for details on the algorithm.
 584
 585   double day = jDay - JD_EPOCH;       // Days since epoch
 586
 587   // Find the angular distance the sun in a fictitious
 588   // circular orbit has travelled since the epoch.
 589   double epochAngle = norm2PI(CalendarAstronomer_PI2/TROPICAL_YEAR*day);
 590
 591   // The epoch wasn't at the sun's perigee; find the angular distance
 592   // since perigee, which is called the "mean anomaly"
 593   meanAnomaly = norm2PI(epochAngle + SUN_ETA_G - SUN_OMEGA_G);
 594
 595   // Now find the "true anomaly", e.g. the real solar longitude
 596   // by solving Kepler's equation for an elliptical orbit
 597   // NOTE: The 3rd ed. of the book lists omega_g and eta_g in different
 598   // equations; omega_g is to be correct.
 599   longitude =  norm2PI(trueAnomaly(meanAnomaly, SUN_E) + SUN_OMEGA_G);
 600 }
 601
 602 /**
 603  * The position of the sun at this object's current date and time,
 604  * in equatorial coordinates.
 605  * @internal
 606  * @deprecated ICU 2.4. This class may be removed or modified.
 607  */
 608 CalendarAstronomer::Equatorial& CalendarAstronomer::getSunPosition(CalendarAstronomer::Equatorial& result) {
 609   return eclipticToEquatorial(result, getSunLongitude(), 0);
 610 }
 611
 612
 613 /**
 614  * Constant representing the vernal equinox.
 615  * For use with {@link #getSunTime getSunTime}.
 616  * Note: In this case, "vernal" refers to the northern hemisphere's seasons.
 617  * @internal
 618  * @deprecated ICU 2.4. This class may be removed or modified.
 619  */
 620 /*double CalendarAstronomer::VERNAL_EQUINOX() {
 621   return 0;
 622 }*/
 623
 624 /**
 625  * Constant representing the summer solstice.
 626  * For use with {@link #getSunTime getSunTime}.
 627  * Note: In this case, "summer" refers to the northern hemisphere's seasons.
 628  * @internal
 629  * @deprecated ICU 2.4. This class may be removed or modified.
 630  */
 631 double CalendarAstronomer::SUMMER_SOLSTICE() {
 632   return  (CalendarAstronomer::PI/2);
 633 }
 634
 635 /**
 636  * Constant representing the autumnal equinox.
 637  * For use with {@link #getSunTime getSunTime}.
 638  * Note: In this case, "autumn" refers to the northern hemisphere's seasons.
 639  * @internal
 640  * @deprecated ICU 2.4. This class may be removed or modified.
 641  */
 642 /*double CalendarAstronomer::AUTUMN_EQUINOX() {
 643   return  (CalendarAstronomer::PI);
 644 }*/
 645
 646 /**
 647  * Constant representing the winter solstice.
 648  * For use with {@link #getSunTime getSunTime}.
 649  * Note: In this case, "winter" refers to the northern hemisphere's seasons.
 650  * @internal
 651  * @deprecated ICU 2.4. This class may be removed or modified.
 652  */
 653 /*double CalendarAstronomer::WINTER_SOLSTICE() {
 654   return  ((CalendarAstronomer::PI*3)/2);
 655 }*/
 656
 657 CalendarAstronomer::AngleFunc::~AngleFunc() {}
 658
 659 /**
 660  * Find the next time at which the sun's ecliptic longitude will have
 661  * the desired value.
 662  * @internal
 663  * @deprecated ICU 2.4. This class may be removed or modified.
 664  */
 665 class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc {
 666 public:
 667   virtual double eval(CalendarAstronomer& a) { return a.getSunLongitude(); }
 668 };
 669
 670 UDate CalendarAstronomer::getSunTime(double desired, UBool next)
 671 {
 672   SunTimeAngleFunc func;
 673   return timeOfAngle( func,
 674                       desired,
 675                       TROPICAL_YEAR,
 676                       MINUTE_MS,
 677                       next);
 678 }
 679
 680 CalendarAstronomer::CoordFunc::~CoordFunc() {}
 681
 682 class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
 683 public:
 684   virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) {  a.getSunPosition(result); }
 685 };
 686
 687 UDate CalendarAstronomer::getSunRiseSet(UBool rise)
 688 {
 689   UDate t0 = fTime;
 690
 691   // Make a rough guess: 6am or 6pm local time on the current day
 692   double noon = Math::floorDivide(fTime + fGmtOffset, (double)DAY_MS)*DAY_MS - fGmtOffset + (12*HOUR_MS);
 693
 694   U_DEBUG_ASTRO_MSG(("Noon=%.2lf, %sL, gmtoff %.2lf\n", noon, debug_astro_date(noon+fGmtOffset), fGmtOffset));
 695   setTime(noon +  ((rise ? -6 : 6) * HOUR_MS));
 696   U_DEBUG_ASTRO_MSG(("added %.2lf ms as a guess,\n", ((rise ? -6. : 6.) * HOUR_MS)));
 697
 698   RiseSetCoordFunc func;
 699   double t = riseOrSet(func,
 700                        rise,
 701                        .533 * DEG_RAD,        // Angular Diameter
 702                        34. /60.0 * DEG_RAD,    // Refraction correction
 703                        MINUTE_MS / 12.);       // Desired accuracy
 704
 705   setTime(t0);
 706   return t;
 707 }
 708
 709 // Commented out - currently unused. ICU 2.6, Alan
 710 //    //-------------------------------------------------------------------------
 711 //    // Alternate Sun Rise/Set
 712 //    // See Duffett-Smith p.93
 713 //    //-------------------------------------------------------------------------
 714 //
 715 //    // This yields worse results (as compared to USNO data) than getSunRiseSet().
 716 //    /**
 717 //     * TODO Make this when the entire class is package-private.
 718 //     */
 719 //    /*public*/ long getSunRiseSet2(boolean rise) {
 720 //        // 1. Calculate coordinates of the sun's center for midnight
 721 //        double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
 722 //        double[] sl = getSunLongitude(jd);//        double lambda1 = sl[0];
 723 //        Equatorial pos1 = eclipticToEquatorial(lambda1, 0);
 724 //
 725 //        // 2. Add ... to lambda to get position 24 hours later
 726 //        double lambda2 = lambda1 + 0.985647*DEG_RAD;
 727 //        Equatorial pos2 = eclipticToEquatorial(lambda2, 0);
 728 //
 729 //        // 3. Calculate LSTs of rising and setting for these two positions
 730 //        double tanL = ::tan(fLatitude);
 731 //        double H = ::acos(-tanL * ::tan(pos1.declination));
 732 //        double lst1r = (CalendarAstronomer_PI2 + pos1.ascension - H) * 24 / CalendarAstronomer_PI2;
 733 //        double lst1s = (pos1.ascension + H) * 24 / CalendarAstronomer_PI2;
 734 //               H = ::acos(-tanL * ::tan(pos2.declination));
 735 //        double lst2r = (CalendarAstronomer_PI2-H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
 736 //        double lst2s = (H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
 737 //        if (lst1r > 24) lst1r -= 24;
 738 //        if (lst1s > 24) lst1s -= 24;
 739 //        if (lst2r > 24) lst2r -= 24;
 740 //        if (lst2s > 24) lst2s -= 24;
 741 //
 742 //        // 4. Convert LSTs to GSTs.  If GST1 > GST2, add 24 to GST2.
 743 //        double gst1r = lstToGst(lst1r);
 744 //        double gst1s = lstToGst(lst1s);
 745 //        double gst2r = lstToGst(lst2r);
 746 //        double gst2s = lstToGst(lst2s);
 747 //        if (gst1r > gst2r) gst2r += 24;
 748 //        if (gst1s > gst2s) gst2s += 24;
 749 //
 750 //        // 5. Calculate GST at 0h UT of this date
 751 //        double t00 = utToGst(0);
 752 //
 753 //        // 6. Calculate GST at 0h on the observer's longitude
 754 //        double offset = ::round(fLongitude*12/PI); // p.95 step 6; he _rounds_ to nearest 15 deg.
 755 //        double t00p = t00 - offset*1.002737909;
 756 //        if (t00p < 0) t00p += 24; // do NOT normalize
 757 //
 758 //        // 7. Adjust
 759 //        if (gst1r < t00p) {
 760 //            gst1r += 24;
 761 //            gst2r += 24;
 762 //        }
 763 //        if (gst1s < t00p) {
 764 //            gst1s += 24;
 765 //            gst2s += 24;
 766 //        }
 767 //
 768 //        // 8.
 769 //        double gstr = (24.07*gst1r-t00*(gst2r-gst1r))/(24.07+gst1r-gst2r);
 770 //        double gsts = (24.07*gst1s-t00*(gst2s-gst1s))/(24.07+gst1s-gst2s);
 771 //
 772 //        // 9. Correct for parallax, refraction, and sun's diameter
 773 //        double dec = (pos1.declination + pos2.declination) / 2;
 774 //        double psi = ::acos(sin(fLatitude) / cos(dec));
 775 //        double x = 0.830725 * DEG_RAD; // parallax+refraction+diameter
 776 //        double y = ::asin(sin(x) / ::sin(psi)) * RAD_DEG;
 777 //        double delta_t = 240 * y / cos(dec) / 3600; // hours
 778 //
 779 //        // 10. Add correction to GSTs, subtract from GSTr
 780 //        gstr -= delta_t;
 781 //        gsts += delta_t;
 782 //
 783 //        // 11. Convert GST to UT and then to local civil time
 784 //        double ut = gstToUt(rise ? gstr : gsts);
 785 //        //System.out.println((rise?"rise=":"set=") + ut + ", delta_t=" + delta_t);
 786 //        long midnight = DAY_MS * (time / DAY_MS); // Find UT midnight on this day
 787 //        return midnight + (long) (ut * 3600000);
 788 //    }
 789
 790 // Commented out - currently unused. ICU 2.6, Alan
 791 //    /**
 792 //     * Convert local sidereal time to Greenwich sidereal time.
 793 //     * Section 15.  Duffett-Smith p.21
 794 //     * @param lst in hours (0..24)
 795 //     * @return GST in hours (0..24)
 796 //     */
 797 //    double lstToGst(double lst) {
 798 //        double delta = fLongitude * 24 / CalendarAstronomer_PI2;
 799 //        return normalize(lst - delta, 24);
 800 //    }
 801
 802 // Commented out - currently unused. ICU 2.6, Alan
 803 //    /**
 804 //     * Convert UT to GST on this date.
 805 //     * Section 12.  Duffett-Smith p.17
 806 //     * @param ut in hours
 807 //     * @return GST in hours
 808 //     */
 809 //    double utToGst(double ut) {
 810 //        return normalize(getT0() + ut*1.002737909, 24);
 811 //    }
 812
 813 // Commented out - currently unused. ICU 2.6, Alan
 814 //    /**
 815 //     * Convert GST to UT on this date.
 816 //     * Section 13.  Duffett-Smith p.18
 817 //     * @param gst in hours
 818 //     * @return UT in hours
 819 //     */
 820 //    double gstToUt(double gst) {
 821 //        return normalize(gst - getT0(), 24) * 0.9972695663;
 822 //    }
 823
 824 // Commented out - currently unused. ICU 2.6, Alan
 825 //    double getT0() {
 826 //        // Common computation for UT <=> GST
 827 //
 828 //        // Find JD for 0h UT
 829 //        double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
 830 //
 831 //        double s = jd - 2451545.0;
 832 //        double t = s / 36525.0;
 833 //        double t0 = 6.697374558 + (2400.051336 + 0.000025862*t)*t;
 834 //        return t0;
 835 //    }
 836
 837 // Commented out - currently unused. ICU 2.6, Alan
 838 //    //-------------------------------------------------------------------------
 839 //    // Alternate Sun Rise/Set
 840 //    // See sci.astro FAQ
 841 //    // http://www.faqs.org/faqs/astronomy/faq/part3/section-5.html
 842 //    //-------------------------------------------------------------------------
 843 //
 844 //    // Note: This method appears to produce inferior accuracy as
 845 //    // compared to getSunRiseSet().
 846 //
 847 //    /**
 848 //     * TODO Make this when the entire class is package-private.
 849 //     */
 850 //    /*public*/ long getSunRiseSet3(boolean rise) {
 851 //
 852 //        // Compute day number for 0.0 Jan 2000 epoch
 853 //        double d = (double)(time - EPOCH_2000_MS) / DAY_MS;
 854 //
 855 //        // Now compute the Local Sidereal Time, LST:
 856 //        //
 857 //        double LST  =  98.9818  +  0.985647352 * d  +  /*UT*15  +  long*/
 858 //            fLongitude*RAD_DEG;
 859 //        //
 860 //        // (east long. positive).  Note that LST is here expressed in degrees,
 861 //        // where 15 degrees corresponds to one hour.  Since LST really is an angle,
 862 //        // it's convenient to use one unit---degrees---throughout.
 863 //
 864 //        //    COMPUTING THE SUN'S POSITION
 865 //        //    ----------------------------
 866 //        //
 867 //        // To be able to compute the Sun's rise/set times, you need to be able to
 868 //        // compute the Sun's position at any time.  First compute the "day
 869 //        // number" d as outlined above, for the desired moment.  Next compute:
 870 //        //
 871 //        double oblecl = 23.4393 - 3.563E-7 * d;
 872 //        //
 873 //        double w  =  282.9404  +  4.70935E-5   * d;
 874 //        double M  =  356.0470  +  0.9856002585 * d;
 875 //        double e  =  0.016709  -  1.151E-9     * d;
 876 //        //
 877 //        // This is the obliquity of the ecliptic, plus some of the elements of
 878 //        // the Sun's apparent orbit (i.e., really the Earth's orbit): w =
 879 //        // argument of perihelion, M = mean anomaly, e = eccentricity.
 880 //        // Semi-major axis is here assumed to be exactly 1.0 (while not strictly
 881 //        // true, this is still an accurate approximation).  Next compute E, the
 882 //        // eccentric anomaly:
 883 //        //
 884 //        double E = M + e*(180/PI) * ::sin(M*DEG_RAD) * ( 1.0 + e*cos(M*DEG_RAD) );
 885 //        //
 886 //        // where E and M are in degrees.  This is it---no further iterations are
 887 //        // needed because we know e has a sufficiently small value.  Next compute
 888 //        // the true anomaly, v, and the distance, r:
 889 //        //
 890 //        /*      r * cos(v)  =  */ double A  =  cos(E*DEG_RAD) - e;
 891 //        /*      r * ::sin(v)  =  */ double B  =  ::sqrt(1 - e*e) * ::sin(E*DEG_RAD);
 892 //        //
 893 //        // and
 894 //        //
 895 //        //      r  =  sqrt( A*A + B*B )
 896 //        double v  =  ::atan2( B, A )*RAD_DEG;
 897 //        //
 898 //        // The Sun's true longitude, slon, can now be computed:
 899 //        //
 900 //        double slon  =  v + w;
 901 //        //
 902 //        // Since the Sun is always at the ecliptic (or at least very very close to
 903 //        // it), we can use simplified formulae to convert slon (the Sun's ecliptic
 904 //        // longitude) to sRA and sDec (the Sun's RA and Dec):
 905 //        //
 906 //        //                   ::sin(slon) * cos(oblecl)
 907 //        //     tan(sRA)  =  -------------------------
 908 //        //            cos(slon)
 909 //        //
 910 //        //     ::sin(sDec) =  ::sin(oblecl) * ::sin(slon)
 911 //        //
 912 //        // As was the case when computing az, the Azimuth, if possible use an
 913 //        // atan2() function to compute sRA.
 914 //
 915 //        double sRA = ::atan2(sin(slon*DEG_RAD) * cos(oblecl*DEG_RAD), cos(slon*DEG_RAD))*RAD_DEG;
 916 //
 917 //        double sin_sDec = ::sin(oblecl*DEG_RAD) * ::sin(slon*DEG_RAD);
 918 //        double sDec = ::asin(sin_sDec)*RAD_DEG;
 919 //
 920 //        //    COMPUTING RISE AND SET TIMES
 921 //        //    ----------------------------
 922 //        //
 923 //        // To compute when an object rises or sets, you must compute when it
 924 //        // passes the meridian and the HA of rise/set.  Then the rise time is
 925 //        // the meridian time minus HA for rise/set, and the set time is the
 926 //        // meridian time plus the HA for rise/set.
 927 //        //
 928 //        // To find the meridian time, compute the Local Sidereal Time at 0h local
 929 //        // time (or 0h UT if you prefer to work in UT) as outlined above---name
 930 //        // that quantity LST0.  The Meridian Time, MT, will now be:
 931 //        //
 932 //        //     MT  =  RA - LST0
 933 //        double MT = normalize(sRA - LST, 360);
 934 //        //
 935 //        // where "RA" is the object's Right Ascension (in degrees!).  If negative,
 936 //        // add 360 deg to MT.  If the object is the Sun, leave the time as it is,
 937 //        // but if it's stellar, multiply MT by 365.2422/366.2422, to convert from
 938 //        // sidereal to solar time.  Now, compute HA for rise/set, name that
 939 //        // quantity HA0:
 940 //        //
 941 //        //                 ::sin(h0)  -  ::sin(lat) * ::sin(Dec)
 942 //        // cos(HA0)  =  ---------------------------------
 943 //        //                      cos(lat) * cos(Dec)
 944 //        //
 945 //        // where h0 is the altitude selected to represent rise/set.  For a purely
 946 //        // mathematical horizon, set h0 = 0 and simplify to:
 947 //        //
 948 //        //    cos(HA0)  =  - tan(lat) * tan(Dec)
 949 //        //
 950 //        // If you want to account for refraction on the atmosphere, set h0 = -35/60
 951 //        // degrees (-35 arc minutes), and if you want to compute the rise/set times
 952 //        // for the Sun's upper limb, set h0 = -50/60 (-50 arc minutes).
 953 //        //
 954 //        double h0 = -50/60 * DEG_RAD;
 955 //
 956 //        double HA0 = ::acos(
 957 //          (sin(h0) - ::sin(fLatitude) * sin_sDec) /
 958 //          (cos(fLatitude) * cos(sDec*DEG_RAD)))*RAD_DEG;
 959 //
 960 //        // When HA0 has been computed, leave it as it is for the Sun but multiply
 961 //        // by 365.2422/366.2422 for stellar objects, to convert from sidereal to
 962 //        // solar time.  Finally compute:
 963 //        //
 964 //        //    Rise time  =  MT - HA0
 965 //        //    Set  time  =  MT + HA0
 966 //        //
 967 //        // convert the times from degrees to hours by dividing by 15.
 968 //        //
 969 //        // If you'd like to check that your calculations are accurate or just
 970 //        // need a quick result, check the USNO's Sun or Moon Rise/Set Table,
 971 //        // <URL:http://aa.usno.navy.mil/AA/data/docs/RS_OneYear.html>.
 972 //
 973 //        double result = MT + (rise ? -HA0 : HA0); // in degrees
 974 //
 975 //        // Find UT midnight on this day
 976 //        long midnight = DAY_MS * (time / DAY_MS);
 977 //
 978 //        return midnight + (long) (result * 3600000 / 15);
 979 //    }
 980
 981 //-------------------------------------------------------------------------
 982 // The Moon
 983 //-------------------------------------------------------------------------
 984
 985 #define moonL0  (318.351648 * CalendarAstronomer::PI/180 )   // Mean long. at epoch
 986 #define moonP0 ( 36.340410 * CalendarAstronomer::PI/180 )   // Mean long. of perigee
 987 #define moonN0 ( 318.510107 * CalendarAstronomer::PI/180 )   // Mean long. of node
 988 #define moonI  (   5.145366 * CalendarAstronomer::PI/180 )   // Inclination of orbit
 989 #define moonE  (   0.054900 )            // Eccentricity of orbit
 990
 991 // These aren't used right now
 992 #define moonA  (   3.84401e5 )           // semi-major axis (km)
 993 #define moonT0 (   0.5181 * CalendarAstronomer::PI/180 )     // Angular size at distance A
 994 #define moonPi (   0.9507 * CalendarAstronomer::PI/180 )     // Parallax at distance A
 995
 996 /**
 997  * The position of the moon at the time set on this
 998  * object, in equatorial coordinates.
 999  * @internal
1000  * @deprecated ICU 2.4. This class may be removed or modified.
1001  */
1002 const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition()
1003 {
1004   //
1005   // See page 142 of "Practial Astronomy with your Calculator",
1006   // by Peter Duffet-Smith, for details on the algorithm.
1007   //
1008   if (moonPositionSet == FALSE) {
1009     // Calculate the solar longitude.  Has the side effect of
1010     // filling in "meanAnomalySun" as well.
1011     getSunLongitude();
1012
1013     //
1014     // Find the # of days since the epoch of our orbital parameters.
1015     // TODO: Convert the time of day portion into ephemeris time
1016     //
1017     double day = getJulianDay() - JD_EPOCH;       // Days since epoch
1018
1019     // Calculate the mean longitude and anomaly of the moon, based on
1020     // a circular orbit.  Similar to the corresponding solar calculation.
1021     double meanLongitude = norm2PI(13.1763966*PI/180*day + moonL0);
1022     meanAnomalyMoon = norm2PI(meanLongitude - 0.1114041*PI/180 * day - moonP0);
1023
1024     //
1025     // Calculate the following corrections:
1026     //  Evection:   the sun's gravity affects the moon's eccentricity
1027     //  Annual Eqn: variation in the effect due to earth-sun distance
1028     //  A3:         correction factor (for ???)
1029     //
1030     double evection = 1.2739*PI/180 * ::sin(2 * (meanLongitude - sunLongitude)
1031                                             - meanAnomalyMoon);
1032     double annual   = 0.1858*PI/180 * ::sin(meanAnomalySun);
1033     double a3       = 0.3700*PI/180 * ::sin(meanAnomalySun);
1034
1035     meanAnomalyMoon += evection - annual - a3;
1036
1037     //
1038     // More correction factors:
1039     //  center  equation of the center correction
1040     //  a4      yet another error correction (???)
1041     //
1042     // TODO: Skip the equation of the center correction and solve Kepler's eqn?
1043     //
1044     double center = 6.2886*PI/180 * ::sin(meanAnomalyMoon);
1045     double a4 =     0.2140*PI/180 * ::sin(2 * meanAnomalyMoon);
1046
1047     // Now find the moon's corrected longitude
1048     moonLongitude = meanLongitude + evection + center - annual + a4;
1049
1050     //
1051     // And finally, find the variation, caused by the fact that the sun's
1052     // gravitational pull on the moon varies depending on which side of
1053     // the earth the moon is on
1054     //
1055     double variation = 0.6583*CalendarAstronomer::PI/180 * ::sin(2*(moonLongitude - sunLongitude));
1056
1057     moonLongitude += variation;
1058
1059     //
1060     // What we've calculated so far is the moon's longitude in the plane
1061     // of its own orbit.  Now map to the ecliptic to get the latitude
1062     // and longitude.  First we need to find the longitude of the ascending
1063     // node, the position on the ecliptic where it is crossed by the moon's
1064     // orbit as it crosses from the southern to the northern hemisphere.
1065     //
1066     double nodeLongitude = norm2PI(moonN0 - 0.0529539*PI/180 * day);
1067
1068     nodeLongitude -= 0.16*PI/180 * ::sin(meanAnomalySun);
1069
1070     double y = ::sin(moonLongitude - nodeLongitude);
1071     double x = cos(moonLongitude - nodeLongitude);
1072
1073     moonEclipLong = ::atan2(y*cos(moonI), x) + nodeLongitude;
1074     double moonEclipLat = ::asin(y * ::sin(moonI));
1075
1076     eclipticToEquatorial(moonPosition, moonEclipLong, moonEclipLat);
1077     moonPositionSet = TRUE;
1078   }
1079   return moonPosition;
1080 }
1081
1082 /**
1083  * The "age" of the moon at the time specified in this object.
1084  * This is really the angle between the
1085  * current ecliptic longitudes of the sun and the moon,
1086  * measured in radians.
1087  *
1088  * @see #getMoonPhase
1089  * @internal
1090  * @deprecated ICU 2.4. This class may be removed or modified.
1091  */
1092 double CalendarAstronomer::getMoonAge() {
1093   // See page 147 of "Practial Astronomy with your Calculator",
1094   // by Peter Duffet-Smith, for details on the algorithm.
1095   //
1096   // Force the moon's position to be calculated.  We're going to use
1097   // some the intermediate results cached during that calculation.
1098   //
1099   getMoonPosition();
1100
1101   return norm2PI(moonEclipLong - sunLongitude);
1102 }
1103
1104 /**
1105  * Calculate the phase of the moon at the time set in this object.
1106  * The returned phase is a <code>double</code> in the range
1107  * <code>0 <= phase < 1</code>, interpreted as follows:
1108  * <ul>
1109  * <li>0.00: New moon
1110  * <li>0.25: First quarter
1111  * <li>0.50: Full moon
1112  * <li>0.75: Last quarter
1113  * </ul>
1114  *
1115  * @see #getMoonAge
1116  * @internal
1117  * @deprecated ICU 2.4. This class may be removed or modified.
1118  */
1119 double CalendarAstronomer::getMoonPhase() {
1120   // See page 147 of "Practial Astronomy with your Calculator",
1121   // by Peter Duffet-Smith, for details on the algorithm.
1122   return 0.5 * (1 - cos(getMoonAge()));
1123 }
1124
1125 /**
1126  * Constant representing a new moon.
1127  * For use with {@link #getMoonTime getMoonTime}
1128  * @internal
1129  * @deprecated ICU 2.4. This class may be removed or modified.
1130  */
1131 /*const CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() {
1132   return  CalendarAstronomer::MoonAge(0);
1133 }*/
1134
1135 /**
1136  * Constant representing the moon's first quarter.
1137  * For use with {@link #getMoonTime getMoonTime}
1138  * @internal
1139  * @deprecated ICU 2.4. This class may be removed or modified.
1140  */
1141 /*const CalendarAstronomer::MoonAge CalendarAstronomer::FIRST_QUARTER() {
1142   return   CalendarAstronomer::MoonAge(CalendarAstronomer::PI/2);
1143 }*/
1144
1145 /**
1146  * Constant representing a full moon.
1147  * For use with {@link #getMoonTime getMoonTime}
1148  * @internal
1149  * @deprecated ICU 2.4. This class may be removed or modified.
1150  */
1151 const CalendarAstronomer::MoonAge CalendarAstronomer::FULL_MOON() {
1152   return   CalendarAstronomer::MoonAge(CalendarAstronomer::PI);
1153 }
1154 /**
1155  * Constant representing the moon's last quarter.
1156  * For use with {@link #getMoonTime getMoonTime}
1157  * @internal
1158  * @deprecated ICU 2.4. This class may be removed or modified.
1159  */
1160
1161 class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc {
1162 public:
1163   virtual double eval(CalendarAstronomer&a) { return a.getMoonAge(); }
1164 };
1165
1166 /*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() {
1167   return  CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2);
1168 }*/
1169
1170 /**
1171  * Find the next or previous time at which the Moon's ecliptic
1172  * longitude will have the desired value.
1173  * <p>
1174  * @param desired   The desired longitude.
1175  * @param next      <tt>true</tt> if the next occurrance of the phase
1176  *                  is desired, <tt>false</tt> for the previous occurrance.
1177  * @internal
1178  * @deprecated ICU 2.4. This class may be removed or modified.
1179  */
1180 UDate CalendarAstronomer::getMoonTime(double desired, UBool next)
1181 {
1182   MoonTimeAngleFunc func;
1183   return timeOfAngle( func,
1184                       desired,
1185                       SYNODIC_MONTH,
1186                       MINUTE_MS,
1187                       next);
1188 }
1189
1190 /**
1191  * Find the next or previous time at which the moon will be in the
1192  * desired phase.
1193  * <p>
1194  * @param desired   The desired phase of the moon.
1195  * @param next      <tt>true</tt> if the next occurrance of the phase
1196  *                  is desired, <tt>false</tt> for the previous occurrance.
1197  * @internal
1198  * @deprecated ICU 2.4. This class may be removed or modified.
1199  */
1200 UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) {
1201   return getMoonTime(desired.value, next);
1202 }
1203
1204 class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
1205 public:
1206   virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { result = a.getMoonPosition(); }
1207 };
1208
1209 /**
1210  * Returns the time (GMT) of sunrise or sunset on the local date to which
1211  * this calendar is currently set.
1212  * @internal
1213  * @deprecated ICU 2.4. This class may be removed or modified.
1214  */
1215 UDate CalendarAstronomer::getMoonRiseSet(UBool rise)
1216 {
1217   MoonRiseSetCoordFunc func;
1218   return riseOrSet(func,
1219                    rise,
1220                    .533 * DEG_RAD,        // Angular Diameter
1221                    34 /60.0 * DEG_RAD,    // Refraction correction
1222                    MINUTE_MS);            // Desired accuracy
1223 }
1224
1225 //-------------------------------------------------------------------------
1226 // Interpolation methods for finding the time at which a given event occurs
1227 //-------------------------------------------------------------------------
1228
1229 UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired,
1230                                       double periodDays, double epsilon, UBool next)
1231 {
1232   // Find the value of the function at the current time
1233   double lastAngle = func.eval(*this);
1234
1235   // Find out how far we are from the desired angle
1236   double deltaAngle = norm2PI(desired - lastAngle) ;
1237
1238   // Using the average period, estimate the next (or previous) time at
1239   // which the desired angle occurs.
1240   double deltaT =  (deltaAngle + (next ? 0.0 : - CalendarAstronomer_PI2 )) * (periodDays*DAY_MS) / CalendarAstronomer_PI2;
1241
1242   double lastDeltaT = deltaT; // Liu
1243   UDate startTime = fTime; // Liu
1244
1245   setTime(fTime + uprv_ceil(deltaT));
1246
1247   // Now iterate until we get the error below epsilon.  Throughout
1248   // this loop we use normPI to get values in the range -Pi to Pi,
1249   // since we're using them as correction factors rather than absolute angles.
1250   do {
1251     // Evaluate the function at the time we've estimated
1252     double angle = func.eval(*this);
1253
1254     // Find the # of milliseconds per radian at this point on the curve
1255     double factor = uprv_fabs(deltaT / normPI(angle-lastAngle));
1256
1257     // Correct the time estimate based on how far off the angle is
1258     deltaT = normPI(desired - angle) * factor;
1259
1260     // HACK:
1261     //
1262     // If abs(deltaT) begins to diverge we need to quit this loop.
1263     // This only appears to happen when attempting to locate, for
1264     // example, a new moon on the day of the new moon.  E.g.:
1265     //
1266     // This result is correct:
1267     // newMoon(7508(Mon Jul 23 00:00:00 CST 1990,false))=
1268     //   Sun Jul 22 10:57:41 CST 1990
1269     //
1270     // But attempting to make the same call a day earlier causes deltaT
1271     // to diverge:
1272     // CalendarAstronomer.timeOfAngle() diverging: 1.348508727575625E9 ->
1273     //   1.3649828540224032E9
1274     // newMoon(7507(Sun Jul 22 00:00:00 CST 1990,false))=
1275     //   Sun Jul 08 13:56:15 CST 1990
1276     //
1277     // As a temporary solution, we catch this specific condition and
1278     // adjust our start time by one eighth period days (either forward
1279     // or backward) and try again.
1280     // Liu 11/9/00
1281     if (uprv_fabs(deltaT) > uprv_fabs(lastDeltaT)) {
1282       double delta = uprv_ceil (periodDays * DAY_MS / 8.0);
1283       setTime(startTime + (next ? delta : -delta));
1284       return timeOfAngle(func, desired, periodDays, epsilon, next);
1285     }
1286
1287     lastDeltaT = deltaT;
1288     lastAngle = angle;
1289
1290     setTime(fTime + uprv_ceil(deltaT));
1291   }
1292   while (uprv_fabs(deltaT) > epsilon);
1293
1294   return fTime;
1295 }
1296
1297 UDate CalendarAstronomer::riseOrSet(CoordFunc& func, UBool rise,
1298                                     double diameter, double refraction,
1299                                     double epsilon)
1300 {
1301   Equatorial pos;
1302   double      tanL   = ::tan(fLatitude);
1303   double     deltaT = 0;
1304   int32_t         count = 0;
1305
1306   //
1307   // Calculate the object's position at the current time, then use that
1308   // position to calculate the time of rising or setting.  The position
1309   // will be different at that time, so iterate until the error is allowable.
1310   //
1311   U_DEBUG_ASTRO_MSG(("setup rise=%s, dia=%.3lf, ref=%.3lf, eps=%.3lf\n",
1312                      rise?"T":"F", diameter, refraction, epsilon));
1313   do {
1314     // See "Practical Astronomy With Your Calculator, section 33.
1315     func.eval(pos, *this);
1316     double angle = ::acos(-tanL * ::tan(pos.declination));
1317     double lst = ((rise ? CalendarAstronomer_PI2-angle : angle) + pos.ascension ) * 24 / CalendarAstronomer_PI2;
1318
1319     // Convert from LST to Universal Time.
1320     UDate newTime = lstToUT( lst );
1321
1322     deltaT = newTime - fTime;
1323     setTime(newTime);
1324     U_DEBUG_ASTRO_MSG(("%d] dT=%.3lf, angle=%.3lf, lst=%.3lf,   A=%.3lf/D=%.3lf\n",
1325                        count, deltaT, angle, lst, pos.ascension, pos.declination));
1326   }
1327   while (++ count < 5 && uprv_fabs(deltaT) > epsilon);
1328
1329   // Calculate the correction due to refraction and the object's angular diameter
1330   double cosD  = ::cos(pos.declination);
1331   double psi   = ::acos(sin(fLatitude) / cosD);
1332   double x     = diameter / 2 + refraction;
1333   double y     = ::asin(sin(x) / ::sin(psi));
1334   long  delta  = (long)((240 * y * RAD_DEG / cosD)*SECOND_MS);
1335
1336   return fTime + (rise ? -delta : delta);
1337 }
1338
1339 /**
1340  * Find the "true anomaly" (longitude) of an object from
1341  * its mean anomaly and the eccentricity of its orbit.  This uses
1342  * an iterative solution to Kepler's equation.
1343  *
1344  * @param meanAnomaly   The object's longitude calculated as if it were in
1345  *                      a regular, circular orbit, measured in radians
1346  *                      from the point of perigee.
1347  *
1348  * @param eccentricity  The eccentricity of the orbit
1349  *
1350  * @return The true anomaly (longitude) measured in radians
1351  */
1352 double CalendarAstronomer::trueAnomaly(double meanAnomaly, double eccentricity)
1353 {
1354   // First, solve Kepler's equation iteratively
1355   // Duffett-Smith, p.90
1356   double delta;
1357   double E = meanAnomaly;
1358   do {
1359     delta = E - eccentricity * ::sin(E) - meanAnomaly;
1360     E = E - delta / (1 - eccentricity * ::cos(E));
1361   }
1362   while (uprv_fabs(delta) > 1e-5); // epsilon = 1e-5 rad
1363
1364   return 2.0 * ::atan( ::tan(E/2) * ::sqrt( (1+eccentricity)
1365                                             /(1-eccentricity) ) );
1366 }
1367
1368 /**
1369  * Return the obliquity of the ecliptic (the angle between the ecliptic
1370  * and the earth's equator) at the current time.  This varies due to
1371  * the precession of the earth's axis.
1372  *
1373  * @return  the obliquity of the ecliptic relative to the equator,
1374  *          measured in radians.
1375  */
1376 double CalendarAstronomer::eclipticObliquity() {
1377   if (isINVALID(eclipObliquity)) {
1378     const double epoch = 2451545.0;     // 2000 AD, January 1.5
1379
1380     double T = (getJulianDay() - epoch) / 36525;
1381
1382     eclipObliquity = 23.439292
1383       - 46.815/3600 * T
1384       - 0.0006/3600 * T*T
1385       + 0.00181/3600 * T*T*T;
1386
1387     eclipObliquity *= DEG_RAD;
1388   }
1389   return eclipObliquity;
1390 }
1391
1392
1393 //-------------------------------------------------------------------------
1394 // Private data
1395 //-------------------------------------------------------------------------
1396 void CalendarAstronomer::clearCache() {
1397   const double INVALID = uprv_getNaN();
1398
1399   julianDay       = INVALID;
1400   julianCentury   = INVALID;
1401   sunLongitude    = INVALID;
1402   meanAnomalySun  = INVALID;
1403   moonLongitude   = INVALID;
1404   moonEclipLong   = INVALID;
1405   meanAnomalyMoon = INVALID;
1406   eclipObliquity  = INVALID;
1407   siderealTime    = INVALID;
1408   siderealT0      = INVALID;
1409   moonPositionSet = FALSE;
1410 }
1411
1412 //private static void out(String s) {
1413 //    System.out.println(s);
1414 //}
1415
1416 //private static String deg(double rad) {
1417 //    return Double.toString(rad * RAD_DEG);
1418 //}
1419
1420 //private static String hours(long ms) {
1421 //    return Double.toString((double)ms / HOUR_MS) + " hours";
1422 //}
1423
1424 /**
1425  * @internal
1426  * @deprecated ICU 2.4. This class may be removed or modified.
1427  */
1428 /*UDate CalendarAstronomer::local(UDate localMillis) {
1429   // TODO - srl ?
1430   TimeZone *tz = TimeZone::createDefault();
1431   int32_t rawOffset;
1432   int32_t dstOffset;
1433   UErrorCode status = U_ZERO_ERROR;
1434   tz->getOffset(localMillis, TRUE, rawOffset, dstOffset, status);
1435   delete tz;
1436   return localMillis - rawOffset;
1437 }*/
1438
1439 // Debugging functions
1440 UnicodeString CalendarAstronomer::Ecliptic::toString() const
1441 {
1442 #ifdef U_DEBUG_ASTRO
1443   char tmp[800];
1444   sprintf(tmp, "[%.5f,%.5f]", longitude*RAD_DEG, latitude*RAD_DEG);
1445   return UnicodeString(tmp, "");
1446 #else
1447   return UnicodeString();
1448 #endif
1449 }
1450
1451 UnicodeString CalendarAstronomer::Equatorial::toString() const
1452 {
1453 #ifdef U_DEBUG_ASTRO
1454   char tmp[400];
1455   sprintf(tmp, "%f,%f",
1456           (ascension*RAD_DEG), (declination*RAD_DEG));
1457   return UnicodeString(tmp, "");
1458 #else
1459   return UnicodeString();
1460 #endif
1461 }
1462
1463 UnicodeString CalendarAstronomer::Horizon::toString() const
1464 {
1465 #ifdef U_DEBUG_ASTRO
1466   char tmp[800];
1467   sprintf(tmp, "[%.5f,%.5f]", altitude*RAD_DEG, azimuth*RAD_DEG);
1468   return UnicodeString(tmp, "");
1469 #else
1470   return UnicodeString();
1471 #endif
1472 }
1473
1474
1475 //  static private String radToHms(double angle) {
1476 //    int hrs = (int) (angle*RAD_HOUR);
1477 //    int min = (int)((angle*RAD_HOUR - hrs) * 60);
1478 //    int sec = (int)((angle*RAD_HOUR - hrs - min/60.0) * 3600);
1479
1480 //    return Integer.toString(hrs) + "h" + min + "m" + sec + "s";
1481 //  }
1482
1483 //  static private String radToDms(double angle) {
1484 //    int deg = (int) (angle*RAD_DEG);
1485 //    int min = (int)((angle*RAD_DEG - deg) * 60);
1486 //    int sec = (int)((angle*RAD_DEG - deg - min/60.0) * 3600);
1487
1488 //    return Integer.toString(deg) + "\u00b0" + min + "'" + sec + "\"";
1489 //  }
1490
1491 // =============== Calendar Cache ================
1492
1493 void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) {
1494   ucln_i18n_registerCleanup(UCLN_I18N_ASTRO_CALENDAR, calendar_astro_cleanup);
1495   if(cache == NULL) {
1496     status = U_MEMORY_ALLOCATION_ERROR;
1497   } else {
1498     *cache = new CalendarCache(32, status);
1499     if(U_FAILURE(status)) {
1500       delete *cache;
1501       *cache = NULL;
1502     }
1503   }
1504 }
1505
1506 int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) {
1507   int32_t res;
1508
1509   if(U_FAILURE(status)) {
1510     return 0;
1511   }
1512   umtx_lock(&ccLock);
1513
1514   if(*cache == NULL) {
1515     createCache(cache, status);
1516     if(U_FAILURE(status)) {
1517       umtx_unlock(&ccLock);
1518       return 0;
1519     }
1520   }
1521
1522   res = uhash_igeti((*cache)->fTable, key);
1523   U_DEBUG_ASTRO_MSG(("%p: GET: [%d] == %d\n", (*cache)->fTable, key, res));
1524
1525   umtx_unlock(&ccLock);
1526   return res;
1527 }
1528
1529 void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) {
1530   if(U_FAILURE(status)) {
1531     return;
1532   }
1533   umtx_lock(&ccLock);
1534
1535   if(*cache == NULL) {
1536     createCache(cache, status);
1537     if(U_FAILURE(status)) {
1538       umtx_unlock(&ccLock);
1539       return;
1540     }
1541   }
1542
1543   uhash_iputi((*cache)->fTable, key, value, &status);
1544   U_DEBUG_ASTRO_MSG(("%p: PUT: [%d] := %d\n", (*cache)->fTable, key, value));
1545
1546   umtx_unlock(&ccLock);
1547 }
1548
1549 CalendarCache::CalendarCache(int32_t size, UErrorCode &status) {
1550   fTable = uhash_openSize(uhash_hashLong, uhash_compareLong, NULL, size, &status);
1551   U_DEBUG_ASTRO_MSG(("%p: Opening.\n", fTable));
1552 }
1553
1554 CalendarCache::~CalendarCache() {
1555   if(fTable != NULL) {
1556     U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable));
1557     uhash_close(fTable);
1558   }
1559 }
1560
1561 U_NAMESPACE_END
1562
1563 #endif //  !UCONFIG_NO_FORMATTING