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1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /************************************************************************
4  * Copyright (C) 1996-2012, International Business Machines Corporation
5  * and others. All Rights Reserved.
6  ************************************************************************
7  *  2003-nov-07   srl       Port from Java
8  */
9 
10 #include "astro.h"
11 
12 #if !UCONFIG_NO_FORMATTING
13 
14 #include "unicode/calendar.h"
15 #include <math.h>
16 #include <float.h>
17 #include "unicode/putil.h"
18 #include "uhash.h"
19 #include "umutex.h"
20 #include "ucln_in.h"
21 #include "putilimp.h"
22 #include <stdio.h>  // for toString()
23 
24 #if defined (PI)
25 #undef PI
26 #endif
27 
28 #ifdef U_DEBUG_ASTRO
29 # include "uresimp.h" // for debugging
30 
debug_astro_loc(const char * f,int32_t l)31 static void debug_astro_loc(const char *f, int32_t l)
32 {
33   fprintf(stderr, "%s:%d: ", f, l);
34 }
35 
debug_astro_msg(const char * pat,...)36 static void debug_astro_msg(const char *pat, ...)
37 {
38   va_list ap;
39   va_start(ap, pat);
40   vfprintf(stderr, pat, ap);
41   fflush(stderr);
42 }
43 #include "unicode/datefmt.h"
44 #include "unicode/ustring.h"
debug_astro_date(UDate d)45 static const char * debug_astro_date(UDate d) {
46   static char gStrBuf[1024];
47   static DateFormat *df = NULL;
48   if(df == NULL) {
49     df = DateFormat::createDateTimeInstance(DateFormat::MEDIUM, DateFormat::MEDIUM, Locale::getUS());
50     df->adoptTimeZone(TimeZone::getGMT()->clone());
51   }
52   UnicodeString str;
53   df->format(d,str);
54   u_austrncpy(gStrBuf,str.getTerminatedBuffer(),sizeof(gStrBuf)-1);
55   return gStrBuf;
56 }
57 
58 // must use double parens, i.e.:  U_DEBUG_ASTRO_MSG(("four is: %d",4));
59 #define U_DEBUG_ASTRO_MSG(x) {debug_astro_loc(__FILE__,__LINE__);debug_astro_msg x;}
60 #else
61 #define U_DEBUG_ASTRO_MSG(x)
62 #endif
63 
isINVALID(double d)64 static inline UBool isINVALID(double d) {
65   return(uprv_isNaN(d));
66 }
67 
68 static UMutex ccLock = U_MUTEX_INITIALIZER;
69 
70 U_CDECL_BEGIN
calendar_astro_cleanup(void)71 static UBool calendar_astro_cleanup(void) {
72   return TRUE;
73 }
74 U_CDECL_END
75 
76 U_NAMESPACE_BEGIN
77 
78 /**
79  * The number of standard hours in one sidereal day.
80  * Approximately 24.93.
81  * @internal
82  * @deprecated ICU 2.4. This class may be removed or modified.
83  */
84 #define SIDEREAL_DAY (23.93446960027)
85 
86 /**
87  * The number of sidereal hours in one mean solar day.
88  * Approximately 24.07.
89  * @internal
90  * @deprecated ICU 2.4. This class may be removed or modified.
91  */
92 #define SOLAR_DAY  (24.065709816)
93 
94 /**
95  * The average number of solar days from one new moon to the next.  This is the time
96  * it takes for the moon to return the same ecliptic longitude as the sun.
97  * It is longer than the sidereal month because the sun's longitude increases
98  * during the year due to the revolution of the earth around the sun.
99  * Approximately 29.53.
100  *
101  * @see #SIDEREAL_MONTH
102  * @internal
103  * @deprecated ICU 2.4. This class may be removed or modified.
104  */
105 const double CalendarAstronomer::SYNODIC_MONTH  = 29.530588853;
106 
107 /**
108  * The average number of days it takes
109  * for the moon to return to the same ecliptic longitude relative to the
110  * stellar background.  This is referred to as the sidereal month.
111  * It is shorter than the synodic month due to
112  * the revolution of the earth around the sun.
113  * Approximately 27.32.
114  *
115  * @see #SYNODIC_MONTH
116  * @internal
117  * @deprecated ICU 2.4. This class may be removed or modified.
118  */
119 #define SIDEREAL_MONTH  27.32166
120 
121 /**
122  * The average number number of days between successive vernal equinoxes.
123  * Due to the precession of the earth's
124  * axis, this is not precisely the same as the sidereal year.
125  * Approximately 365.24
126  *
127  * @see #SIDEREAL_YEAR
128  * @internal
129  * @deprecated ICU 2.4. This class may be removed or modified.
130  */
131 #define TROPICAL_YEAR  365.242191
132 
133 /**
134  * The average number of days it takes
135  * for the sun to return to the same position against the fixed stellar
136  * background.  This is the duration of one orbit of the earth about the sun
137  * as it would appear to an outside observer.
138  * Due to the precession of the earth's
139  * axis, this is not precisely the same as the tropical year.
140  * Approximately 365.25.
141  *
142  * @see #TROPICAL_YEAR
143  * @internal
144  * @deprecated ICU 2.4. This class may be removed or modified.
145  */
146 #define SIDEREAL_YEAR  365.25636
147 
148 //-------------------------------------------------------------------------
149 // Time-related constants
150 //-------------------------------------------------------------------------
151 
152 /**
153  * The number of milliseconds in one second.
154  * @internal
155  * @deprecated ICU 2.4. This class may be removed or modified.
156  */
157 #define SECOND_MS  U_MILLIS_PER_SECOND
158 
159 /**
160  * The number of milliseconds in one minute.
161  * @internal
162  * @deprecated ICU 2.4. This class may be removed or modified.
163  */
164 #define MINUTE_MS  U_MILLIS_PER_MINUTE
165 
166 /**
167  * The number of milliseconds in one hour.
168  * @internal
169  * @deprecated ICU 2.4. This class may be removed or modified.
170  */
171 #define HOUR_MS   U_MILLIS_PER_HOUR
172 
173 /**
174  * The number of milliseconds in one day.
175  * @internal
176  * @deprecated ICU 2.4. This class may be removed or modified.
177  */
178 #define DAY_MS U_MILLIS_PER_DAY
179 
180 /**
181  * The start of the julian day numbering scheme used by astronomers, which
182  * is 1/1/4713 BC (Julian), 12:00 GMT.  This is given as the number of milliseconds
183  * since 1/1/1970 AD (Gregorian), a negative number.
184  * Note that julian day numbers and
185  * the Julian calendar are <em>not</em> the same thing.  Also note that
186  * julian days start at <em>noon</em>, not midnight.
187  * @internal
188  * @deprecated ICU 2.4. This class may be removed or modified.
189  */
190 #define JULIAN_EPOCH_MS  -210866760000000.0
191 
192 
193 /**
194  * Milliseconds value for 0.0 January 2000 AD.
195  */
196 #define EPOCH_2000_MS  946598400000.0
197 
198 //-------------------------------------------------------------------------
199 // Assorted private data used for conversions
200 //-------------------------------------------------------------------------
201 
202 // My own copies of these so compilers are more likely to optimize them away
203 const double CalendarAstronomer::PI = 3.14159265358979323846;
204 
205 #define CalendarAstronomer_PI2  (CalendarAstronomer::PI*2.0)
206 #define RAD_HOUR  ( 12 / CalendarAstronomer::PI )     // radians -> hours
207 #define DEG_RAD ( CalendarAstronomer::PI / 180 )      // degrees -> radians
208 #define RAD_DEG  ( 180 / CalendarAstronomer::PI )     // radians -> degrees
209 
210 /***
211  * Given 'value', add or subtract 'range' until 0 <= 'value' < range.
212  * The modulus operator.
213  */
normalize(double value,double range)214 inline static double normalize(double value, double range)  {
215     return value - range * ClockMath::floorDivide(value, range);
216 }
217 
218 /**
219  * Normalize an angle so that it's in the range 0 - 2pi.
220  * For positive angles this is just (angle % 2pi), but the Java
221  * mod operator doesn't work that way for negative numbers....
222  */
norm2PI(double angle)223 inline static double norm2PI(double angle)  {
224     return normalize(angle, CalendarAstronomer::PI * 2.0);
225 }
226 
227 /**
228  * Normalize an angle into the range -PI - PI
229  */
normPI(double angle)230 inline static  double normPI(double angle)  {
231     return normalize(angle + CalendarAstronomer::PI, CalendarAstronomer::PI * 2.0) - CalendarAstronomer::PI;
232 }
233 
234 //-------------------------------------------------------------------------
235 // Constructors
236 //-------------------------------------------------------------------------
237 
238 /**
239  * Construct a new <code>CalendarAstronomer</code> object that is initialized to
240  * the current date and time.
241  * @internal
242  * @deprecated ICU 2.4. This class may be removed or modified.
243  */
CalendarAstronomer()244 CalendarAstronomer::CalendarAstronomer():
245   fTime(Calendar::getNow()), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
246   clearCache();
247 }
248 
249 /**
250  * Construct a new <code>CalendarAstronomer</code> object that is initialized to
251  * the specified date and time.
252  * @internal
253  * @deprecated ICU 2.4. This class may be removed or modified.
254  */
CalendarAstronomer(UDate d)255 CalendarAstronomer::CalendarAstronomer(UDate d): fTime(d), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
256   clearCache();
257 }
258 
259 /**
260  * Construct a new <code>CalendarAstronomer</code> object with the given
261  * latitude and longitude.  The object's time is set to the current
262  * date and time.
263  * <p>
264  * @param longitude The desired longitude, in <em>degrees</em> east of
265  *                  the Greenwich meridian.
266  *
267  * @param latitude  The desired latitude, in <em>degrees</em>.  Positive
268  *                  values signify North, negative South.
269  *
270  * @see java.util.Date#getTime()
271  * @internal
272  * @deprecated ICU 2.4. This class may be removed or modified.
273  */
CalendarAstronomer(double longitude,double latitude)274 CalendarAstronomer::CalendarAstronomer(double longitude, double latitude) :
275   fTime(Calendar::getNow()), moonPosition(0,0), moonPositionSet(FALSE) {
276   fLongitude = normPI(longitude * (double)DEG_RAD);
277   fLatitude  = normPI(latitude  * (double)DEG_RAD);
278   fGmtOffset = (double)(fLongitude * 24. * (double)HOUR_MS / (double)CalendarAstronomer_PI2);
279   clearCache();
280 }
281 
~CalendarAstronomer()282 CalendarAstronomer::~CalendarAstronomer()
283 {
284 }
285 
286 //-------------------------------------------------------------------------
287 // Time and date getters and setters
288 //-------------------------------------------------------------------------
289 
290 /**
291  * Set the current date and time of this <code>CalendarAstronomer</code> object.  All
292  * astronomical calculations are performed based on this time setting.
293  *
294  * @param aTime the date and time, expressed as the number of milliseconds since
295  *              1/1/1970 0:00 GMT (Gregorian).
296  *
297  * @see #setDate
298  * @see #getTime
299  * @internal
300  * @deprecated ICU 2.4. This class may be removed or modified.
301  */
setTime(UDate aTime)302 void CalendarAstronomer::setTime(UDate aTime) {
303     fTime = aTime;
304     U_DEBUG_ASTRO_MSG(("setTime(%.1lf, %sL)\n", aTime, debug_astro_date(aTime+fGmtOffset)));
305     clearCache();
306 }
307 
308 /**
309  * Set the current date and time of this <code>CalendarAstronomer</code> object.  All
310  * astronomical calculations are performed based on this time setting.
311  *
312  * @param jdn   the desired time, expressed as a "julian day number",
313  *              which is the number of elapsed days since
314  *              1/1/4713 BC (Julian), 12:00 GMT.  Note that julian day
315  *              numbers start at <em>noon</em>.  To get the jdn for
316  *              the corresponding midnight, subtract 0.5.
317  *
318  * @see #getJulianDay
319  * @see #JULIAN_EPOCH_MS
320  * @internal
321  * @deprecated ICU 2.4. This class may be removed or modified.
322  */
setJulianDay(double jdn)323 void CalendarAstronomer::setJulianDay(double jdn) {
324     fTime = (double)(jdn * DAY_MS) + JULIAN_EPOCH_MS;
325     clearCache();
326     julianDay = jdn;
327 }
328 
329 /**
330  * Get the current time of this <code>CalendarAstronomer</code> object,
331  * represented as the number of milliseconds since
332  * 1/1/1970 AD 0:00 GMT (Gregorian).
333  *
334  * @see #setTime
335  * @see #getDate
336  * @internal
337  * @deprecated ICU 2.4. This class may be removed or modified.
338  */
getTime()339 UDate CalendarAstronomer::getTime() {
340     return fTime;
341 }
342 
343 /**
344  * Get the current time of this <code>CalendarAstronomer</code> object,
345  * expressed as a "julian day number", which is the number of elapsed
346  * days since 1/1/4713 BC (Julian), 12:00 GMT.
347  *
348  * @see #setJulianDay
349  * @see #JULIAN_EPOCH_MS
350  * @internal
351  * @deprecated ICU 2.4. This class may be removed or modified.
352  */
getJulianDay()353 double CalendarAstronomer::getJulianDay() {
354     if (isINVALID(julianDay)) {
355         julianDay = (fTime - (double)JULIAN_EPOCH_MS) / (double)DAY_MS;
356     }
357     return julianDay;
358 }
359 
360 /**
361  * Return this object's time expressed in julian centuries:
362  * the number of centuries after 1/1/1900 AD, 12:00 GMT
363  *
364  * @see #getJulianDay
365  * @internal
366  * @deprecated ICU 2.4. This class may be removed or modified.
367  */
getJulianCentury()368 double CalendarAstronomer::getJulianCentury() {
369     if (isINVALID(julianCentury)) {
370         julianCentury = (getJulianDay() - 2415020.0) / 36525.0;
371     }
372     return julianCentury;
373 }
374 
375 /**
376  * Returns the current Greenwich sidereal time, measured in hours
377  * @internal
378  * @deprecated ICU 2.4. This class may be removed or modified.
379  */
getGreenwichSidereal()380 double CalendarAstronomer::getGreenwichSidereal() {
381     if (isINVALID(siderealTime)) {
382         // See page 86 of "Practial Astronomy with your Calculator",
383         // by Peter Duffet-Smith, for details on the algorithm.
384 
385         double UT = normalize(fTime/(double)HOUR_MS, 24.);
386 
387         siderealTime = normalize(getSiderealOffset() + UT*1.002737909, 24.);
388     }
389     return siderealTime;
390 }
391 
getSiderealOffset()392 double CalendarAstronomer::getSiderealOffset() {
393     if (isINVALID(siderealT0)) {
394         double JD  = uprv_floor(getJulianDay() - 0.5) + 0.5;
395         double S   = JD - 2451545.0;
396         double T   = S / 36525.0;
397         siderealT0 = normalize(6.697374558 + 2400.051336*T + 0.000025862*T*T, 24);
398     }
399     return siderealT0;
400 }
401 
402 /**
403  * Returns the current local sidereal time, measured in hours
404  * @internal
405  * @deprecated ICU 2.4. This class may be removed or modified.
406  */
getLocalSidereal()407 double CalendarAstronomer::getLocalSidereal() {
408     return normalize(getGreenwichSidereal() + (fGmtOffset/(double)HOUR_MS), 24.);
409 }
410 
411 /**
412  * Converts local sidereal time to Universal Time.
413  *
414  * @param lst   The Local Sidereal Time, in hours since sidereal midnight
415  *              on this object's current date.
416  *
417  * @return      The corresponding Universal Time, in milliseconds since
418  *              1 Jan 1970, GMT.
419  */
lstToUT(double lst)420 double CalendarAstronomer::lstToUT(double lst) {
421     // Convert to local mean time
422     double lt = normalize((lst - getSiderealOffset()) * 0.9972695663, 24);
423 
424     // Then find local midnight on this day
425     double base = (DAY_MS * ClockMath::floorDivide(fTime + fGmtOffset,(double)DAY_MS)) - fGmtOffset;
426 
427     //out("    lt  =" + lt + " hours");
428     //out("    base=" + new Date(base));
429 
430     return base + (long)(lt * HOUR_MS);
431 }
432 
433 
434 //-------------------------------------------------------------------------
435 // Coordinate transformations, all based on the current time of this object
436 //-------------------------------------------------------------------------
437 
438 /**
439  * Convert from ecliptic to equatorial coordinates.
440  *
441  * @param ecliptic  A point in the sky in ecliptic coordinates.
442  * @return          The corresponding point in equatorial coordinates.
443  * @internal
444  * @deprecated ICU 2.4. This class may be removed or modified.
445  */
eclipticToEquatorial(CalendarAstronomer::Equatorial & result,const CalendarAstronomer::Ecliptic & ecliptic)446 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, const CalendarAstronomer::Ecliptic& ecliptic)
447 {
448     return eclipticToEquatorial(result, ecliptic.longitude, ecliptic.latitude);
449 }
450 
451 /**
452  * Convert from ecliptic to equatorial coordinates.
453  *
454  * @param eclipLong     The ecliptic longitude
455  * @param eclipLat      The ecliptic latitude
456  *
457  * @return              The corresponding point in equatorial coordinates.
458  * @internal
459  * @deprecated ICU 2.4. This class may be removed or modified.
460  */
eclipticToEquatorial(CalendarAstronomer::Equatorial & result,double eclipLong,double eclipLat)461 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat)
462 {
463     // See page 42 of "Practial Astronomy with your Calculator",
464     // by Peter Duffet-Smith, for details on the algorithm.
465 
466     double obliq = eclipticObliquity();
467     double sinE = ::sin(obliq);
468     double cosE = cos(obliq);
469 
470     double sinL = ::sin(eclipLong);
471     double cosL = cos(eclipLong);
472 
473     double sinB = ::sin(eclipLat);
474     double cosB = cos(eclipLat);
475     double tanB = tan(eclipLat);
476 
477     result.set(atan2(sinL*cosE - tanB*sinE, cosL),
478         asin(sinB*cosE + cosB*sinE*sinL) );
479     return result;
480 }
481 
482 /**
483  * Convert from ecliptic longitude to equatorial coordinates.
484  *
485  * @param eclipLong     The ecliptic longitude
486  *
487  * @return              The corresponding point in equatorial coordinates.
488  * @internal
489  * @deprecated ICU 2.4. This class may be removed or modified.
490  */
eclipticToEquatorial(CalendarAstronomer::Equatorial & result,double eclipLong)491 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong)
492 {
493     return eclipticToEquatorial(result, eclipLong, 0);  // TODO: optimize
494 }
495 
496 /**
497  * @internal
498  * @deprecated ICU 2.4. This class may be removed or modified.
499  */
eclipticToHorizon(CalendarAstronomer::Horizon & result,double eclipLong)500 CalendarAstronomer::Horizon& CalendarAstronomer::eclipticToHorizon(CalendarAstronomer::Horizon& result, double eclipLong)
501 {
502     Equatorial equatorial;
503     eclipticToEquatorial(equatorial, eclipLong);
504 
505     double H = getLocalSidereal()*CalendarAstronomer::PI/12 - equatorial.ascension;     // Hour-angle
506 
507     double sinH = ::sin(H);
508     double cosH = cos(H);
509     double sinD = ::sin(equatorial.declination);
510     double cosD = cos(equatorial.declination);
511     double sinL = ::sin(fLatitude);
512     double cosL = cos(fLatitude);
513 
514     double altitude = asin(sinD*sinL + cosD*cosL*cosH);
515     double azimuth  = atan2(-cosD*cosL*sinH, sinD - sinL * ::sin(altitude));
516 
517     result.set(azimuth, altitude);
518     return result;
519 }
520 
521 
522 //-------------------------------------------------------------------------
523 // The Sun
524 //-------------------------------------------------------------------------
525 
526 //
527 // Parameters of the Sun's orbit as of the epoch Jan 0.0 1990
528 // Angles are in radians (after multiplying by CalendarAstronomer::PI/180)
529 //
530 #define JD_EPOCH  2447891.5 // Julian day of epoch
531 
532 #define SUN_ETA_G    (279.403303 * CalendarAstronomer::PI/180) // Ecliptic longitude at epoch
533 #define SUN_OMEGA_G  (282.768422 * CalendarAstronomer::PI/180) // Ecliptic longitude of perigee
534 #define SUN_E         0.016713          // Eccentricity of orbit
535 //double sunR0        1.495585e8        // Semi-major axis in KM
536 //double sunTheta0    (0.533128 * CalendarAstronomer::PI/180) // Angular diameter at R0
537 
538 // The following three methods, which compute the sun parameters
539 // given above for an arbitrary epoch (whatever time the object is
540 // set to), make only a small difference as compared to using the
541 // above constants.  E.g., Sunset times might differ by ~12
542 // seconds.  Furthermore, the eta-g computation is befuddled by
543 // Duffet-Smith's incorrect coefficients (p.86).  I've corrected
544 // the first-order coefficient but the others may be off too - no
545 // way of knowing without consulting another source.
546 
547 //  /**
548 //   * Return the sun's ecliptic longitude at perigee for the current time.
549 //   * See Duffett-Smith, p. 86.
550 //   * @return radians
551 //   */
552 //  private double getSunOmegaG() {
553 //      double T = getJulianCentury();
554 //      return (281.2208444 + (1.719175 + 0.000452778*T)*T) * DEG_RAD;
555 //  }
556 
557 //  /**
558 //   * Return the sun's ecliptic longitude for the current time.
559 //   * See Duffett-Smith, p. 86.
560 //   * @return radians
561 //   */
562 //  private double getSunEtaG() {
563 //      double T = getJulianCentury();
564 //      //return (279.6966778 + (36000.76892 + 0.0003025*T)*T) * DEG_RAD;
565 //      //
566 //      // The above line is from Duffett-Smith, and yields manifestly wrong
567 //      // results.  The below constant is derived empirically to match the
568 //      // constant he gives for the 1990 EPOCH.
569 //      //
570 //      return (279.6966778 + (-0.3262541582718024 + 0.0003025*T)*T) * DEG_RAD;
571 //  }
572 
573 //  /**
574 //   * Return the sun's eccentricity of orbit for the current time.
575 //   * See Duffett-Smith, p. 86.
576 //   * @return double
577 //   */
578 //  private double getSunE() {
579 //      double T = getJulianCentury();
580 //      return 0.01675104 - (0.0000418 + 0.000000126*T)*T;
581 //  }
582 
583 /**
584  * Find the "true anomaly" (longitude) of an object from
585  * its mean anomaly and the eccentricity of its orbit.  This uses
586  * an iterative solution to Kepler's equation.
587  *
588  * @param meanAnomaly   The object's longitude calculated as if it were in
589  *                      a regular, circular orbit, measured in radians
590  *                      from the point of perigee.
591  *
592  * @param eccentricity  The eccentricity of the orbit
593  *
594  * @return The true anomaly (longitude) measured in radians
595  */
trueAnomaly(double meanAnomaly,double eccentricity)596 static double trueAnomaly(double meanAnomaly, double eccentricity)
597 {
598     // First, solve Kepler's equation iteratively
599     // Duffett-Smith, p.90
600     double delta;
601     double E = meanAnomaly;
602     do {
603         delta = E - eccentricity * ::sin(E) - meanAnomaly;
604         E = E - delta / (1 - eccentricity * ::cos(E));
605     }
606     while (uprv_fabs(delta) > 1e-5); // epsilon = 1e-5 rad
607 
608     return 2.0 * ::atan( ::tan(E/2) * ::sqrt( (1+eccentricity)
609                                              /(1-eccentricity) ) );
610 }
611 
612 /**
613  * The longitude of the sun at the time specified by this object.
614  * The longitude is measured in radians along the ecliptic
615  * from the "first point of Aries," the point at which the ecliptic
616  * crosses the earth's equatorial plane at the vernal equinox.
617  * <p>
618  * Currently, this method uses an approximation of the two-body Kepler's
619  * equation for the earth and the sun.  It does not take into account the
620  * perturbations caused by the other planets, the moon, etc.
621  * @internal
622  * @deprecated ICU 2.4. This class may be removed or modified.
623  */
getSunLongitude()624 double CalendarAstronomer::getSunLongitude()
625 {
626     // See page 86 of "Practial Astronomy with your Calculator",
627     // by Peter Duffet-Smith, for details on the algorithm.
628 
629     if (isINVALID(sunLongitude)) {
630         getSunLongitude(getJulianDay(), sunLongitude, meanAnomalySun);
631     }
632     return sunLongitude;
633 }
634 
635 /**
636  * TODO Make this public when the entire class is package-private.
637  */
getSunLongitude(double jDay,double & longitude,double & meanAnomaly)638 /*public*/ void CalendarAstronomer::getSunLongitude(double jDay, double &longitude, double &meanAnomaly)
639 {
640     // See page 86 of "Practial Astronomy with your Calculator",
641     // by Peter Duffet-Smith, for details on the algorithm.
642 
643     double day = jDay - JD_EPOCH;       // Days since epoch
644 
645     // Find the angular distance the sun in a fictitious
646     // circular orbit has travelled since the epoch.
647     double epochAngle = norm2PI(CalendarAstronomer_PI2/TROPICAL_YEAR*day);
648 
649     // The epoch wasn't at the sun's perigee; find the angular distance
650     // since perigee, which is called the "mean anomaly"
651     meanAnomaly = norm2PI(epochAngle + SUN_ETA_G - SUN_OMEGA_G);
652 
653     // Now find the "true anomaly", e.g. the real solar longitude
654     // by solving Kepler's equation for an elliptical orbit
655     // NOTE: The 3rd ed. of the book lists omega_g and eta_g in different
656     // equations; omega_g is to be correct.
657     longitude =  norm2PI(trueAnomaly(meanAnomaly, SUN_E) + SUN_OMEGA_G);
658 }
659 
660 /**
661  * The position of the sun at this object's current date and time,
662  * in equatorial coordinates.
663  * @internal
664  * @deprecated ICU 2.4. This class may be removed or modified.
665  */
getSunPosition(CalendarAstronomer::Equatorial & result)666 CalendarAstronomer::Equatorial& CalendarAstronomer::getSunPosition(CalendarAstronomer::Equatorial& result) {
667     return eclipticToEquatorial(result, getSunLongitude(), 0);
668 }
669 
670 
671 /**
672  * Constant representing the vernal equinox.
673  * For use with {@link #getSunTime getSunTime}.
674  * Note: In this case, "vernal" refers to the northern hemisphere's seasons.
675  * @internal
676  * @deprecated ICU 2.4. This class may be removed or modified.
677  */
678 /*double CalendarAstronomer::VERNAL_EQUINOX() {
679   return 0;
680 }*/
681 
682 /**
683  * Constant representing the summer solstice.
684  * For use with {@link #getSunTime getSunTime}.
685  * Note: In this case, "summer" refers to the northern hemisphere's seasons.
686  * @internal
687  * @deprecated ICU 2.4. This class may be removed or modified.
688  */
SUMMER_SOLSTICE()689 double CalendarAstronomer::SUMMER_SOLSTICE() {
690     return  (CalendarAstronomer::PI/2);
691 }
692 
693 /**
694  * Constant representing the autumnal equinox.
695  * For use with {@link #getSunTime getSunTime}.
696  * Note: In this case, "autumn" refers to the northern hemisphere's seasons.
697  * @internal
698  * @deprecated ICU 2.4. This class may be removed or modified.
699  */
700 /*double CalendarAstronomer::AUTUMN_EQUINOX() {
701   return  (CalendarAstronomer::PI);
702 }*/
703 
704 /**
705  * Constant representing the winter solstice.
706  * For use with {@link #getSunTime getSunTime}.
707  * Note: In this case, "winter" refers to the northern hemisphere's seasons.
708  * @internal
709  * @deprecated ICU 2.4. This class may be removed or modified.
710  */
WINTER_SOLSTICE()711 double CalendarAstronomer::WINTER_SOLSTICE() {
712     return  ((CalendarAstronomer::PI*3)/2);
713 }
714 
~AngleFunc()715 CalendarAstronomer::AngleFunc::~AngleFunc() {}
716 
717 /**
718  * Find the next time at which the sun's ecliptic longitude will have
719  * the desired value.
720  * @internal
721  * @deprecated ICU 2.4. This class may be removed or modified.
722  */
723 class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc {
724 public:
725     virtual ~SunTimeAngleFunc();
eval(CalendarAstronomer & a)726     virtual double eval(CalendarAstronomer& a) { return a.getSunLongitude(); }
727 };
728 
~SunTimeAngleFunc()729 SunTimeAngleFunc::~SunTimeAngleFunc() {}
730 
getSunTime(double desired,UBool next)731 UDate CalendarAstronomer::getSunTime(double desired, UBool next)
732 {
733     SunTimeAngleFunc func;
734     return timeOfAngle( func,
735                         desired,
736                         TROPICAL_YEAR,
737                         MINUTE_MS,
738                         next);
739 }
740 
~CoordFunc()741 CalendarAstronomer::CoordFunc::~CoordFunc() {}
742 
743 class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
744 public:
745     virtual ~RiseSetCoordFunc();
eval(CalendarAstronomer::Equatorial & result,CalendarAstronomer & a)746     virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) {  a.getSunPosition(result); }
747 };
748 
~RiseSetCoordFunc()749 RiseSetCoordFunc::~RiseSetCoordFunc() {}
750 
getSunRiseSet(UBool rise)751 UDate CalendarAstronomer::getSunRiseSet(UBool rise)
752 {
753     UDate t0 = fTime;
754 
755     // Make a rough guess: 6am or 6pm local time on the current day
756     double noon = ClockMath::floorDivide(fTime + fGmtOffset, (double)DAY_MS)*DAY_MS - fGmtOffset + (12*HOUR_MS);
757 
758     U_DEBUG_ASTRO_MSG(("Noon=%.2lf, %sL, gmtoff %.2lf\n", noon, debug_astro_date(noon+fGmtOffset), fGmtOffset));
759     setTime(noon +  ((rise ? -6 : 6) * HOUR_MS));
760     U_DEBUG_ASTRO_MSG(("added %.2lf ms as a guess,\n", ((rise ? -6. : 6.) * HOUR_MS)));
761 
762     RiseSetCoordFunc func;
763     double t = riseOrSet(func,
764                          rise,
765                          .533 * DEG_RAD,        // Angular Diameter
766                          34. /60.0 * DEG_RAD,    // Refraction correction
767                          MINUTE_MS / 12.);       // Desired accuracy
768 
769     setTime(t0);
770     return t;
771 }
772 
773 // Commented out - currently unused. ICU 2.6, Alan
774 //    //-------------------------------------------------------------------------
775 //    // Alternate Sun Rise/Set
776 //    // See Duffett-Smith p.93
777 //    //-------------------------------------------------------------------------
778 //
779 //    // This yields worse results (as compared to USNO data) than getSunRiseSet().
780 //    /**
781 //     * TODO Make this when the entire class is package-private.
782 //     */
783 //    /*public*/ long getSunRiseSet2(boolean rise) {
784 //        // 1. Calculate coordinates of the sun's center for midnight
785 //        double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
786 //        double[] sl = getSunLongitude(jd);//        double lambda1 = sl[0];
787 //        Equatorial pos1 = eclipticToEquatorial(lambda1, 0);
788 //
789 //        // 2. Add ... to lambda to get position 24 hours later
790 //        double lambda2 = lambda1 + 0.985647*DEG_RAD;
791 //        Equatorial pos2 = eclipticToEquatorial(lambda2, 0);
792 //
793 //        // 3. Calculate LSTs of rising and setting for these two positions
794 //        double tanL = ::tan(fLatitude);
795 //        double H = ::acos(-tanL * ::tan(pos1.declination));
796 //        double lst1r = (CalendarAstronomer_PI2 + pos1.ascension - H) * 24 / CalendarAstronomer_PI2;
797 //        double lst1s = (pos1.ascension + H) * 24 / CalendarAstronomer_PI2;
798 //               H = ::acos(-tanL * ::tan(pos2.declination));
799 //        double lst2r = (CalendarAstronomer_PI2-H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
800 //        double lst2s = (H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
801 //        if (lst1r > 24) lst1r -= 24;
802 //        if (lst1s > 24) lst1s -= 24;
803 //        if (lst2r > 24) lst2r -= 24;
804 //        if (lst2s > 24) lst2s -= 24;
805 //
806 //        // 4. Convert LSTs to GSTs.  If GST1 > GST2, add 24 to GST2.
807 //        double gst1r = lstToGst(lst1r);
808 //        double gst1s = lstToGst(lst1s);
809 //        double gst2r = lstToGst(lst2r);
810 //        double gst2s = lstToGst(lst2s);
811 //        if (gst1r > gst2r) gst2r += 24;
812 //        if (gst1s > gst2s) gst2s += 24;
813 //
814 //        // 5. Calculate GST at 0h UT of this date
815 //        double t00 = utToGst(0);
816 //
817 //        // 6. Calculate GST at 0h on the observer's longitude
818 //        double offset = ::round(fLongitude*12/PI); // p.95 step 6; he _rounds_ to nearest 15 deg.
819 //        double t00p = t00 - offset*1.002737909;
820 //        if (t00p < 0) t00p += 24; // do NOT normalize
821 //
822 //        // 7. Adjust
823 //        if (gst1r < t00p) {
824 //            gst1r += 24;
825 //            gst2r += 24;
826 //        }
827 //        if (gst1s < t00p) {
828 //            gst1s += 24;
829 //            gst2s += 24;
830 //        }
831 //
832 //        // 8.
833 //        double gstr = (24.07*gst1r-t00*(gst2r-gst1r))/(24.07+gst1r-gst2r);
834 //        double gsts = (24.07*gst1s-t00*(gst2s-gst1s))/(24.07+gst1s-gst2s);
835 //
836 //        // 9. Correct for parallax, refraction, and sun's diameter
837 //        double dec = (pos1.declination + pos2.declination) / 2;
838 //        double psi = ::acos(sin(fLatitude) / cos(dec));
839 //        double x = 0.830725 * DEG_RAD; // parallax+refraction+diameter
840 //        double y = ::asin(sin(x) / ::sin(psi)) * RAD_DEG;
841 //        double delta_t = 240 * y / cos(dec) / 3600; // hours
842 //
843 //        // 10. Add correction to GSTs, subtract from GSTr
844 //        gstr -= delta_t;
845 //        gsts += delta_t;
846 //
847 //        // 11. Convert GST to UT and then to local civil time
848 //        double ut = gstToUt(rise ? gstr : gsts);
849 //        //System.out.println((rise?"rise=":"set=") + ut + ", delta_t=" + delta_t);
850 //        long midnight = DAY_MS * (time / DAY_MS); // Find UT midnight on this day
851 //        return midnight + (long) (ut * 3600000);
852 //    }
853 
854 // Commented out - currently unused. ICU 2.6, Alan
855 //    /**
856 //     * Convert local sidereal time to Greenwich sidereal time.
857 //     * Section 15.  Duffett-Smith p.21
858 //     * @param lst in hours (0..24)
859 //     * @return GST in hours (0..24)
860 //     */
861 //    double lstToGst(double lst) {
862 //        double delta = fLongitude * 24 / CalendarAstronomer_PI2;
863 //        return normalize(lst - delta, 24);
864 //    }
865 
866 // Commented out - currently unused. ICU 2.6, Alan
867 //    /**
868 //     * Convert UT to GST on this date.
869 //     * Section 12.  Duffett-Smith p.17
870 //     * @param ut in hours
871 //     * @return GST in hours
872 //     */
873 //    double utToGst(double ut) {
874 //        return normalize(getT0() + ut*1.002737909, 24);
875 //    }
876 
877 // Commented out - currently unused. ICU 2.6, Alan
878 //    /**
879 //     * Convert GST to UT on this date.
880 //     * Section 13.  Duffett-Smith p.18
881 //     * @param gst in hours
882 //     * @return UT in hours
883 //     */
884 //    double gstToUt(double gst) {
885 //        return normalize(gst - getT0(), 24) * 0.9972695663;
886 //    }
887 
888 // Commented out - currently unused. ICU 2.6, Alan
889 //    double getT0() {
890 //        // Common computation for UT <=> GST
891 //
892 //        // Find JD for 0h UT
893 //        double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
894 //
895 //        double s = jd - 2451545.0;
896 //        double t = s / 36525.0;
897 //        double t0 = 6.697374558 + (2400.051336 + 0.000025862*t)*t;
898 //        return t0;
899 //    }
900 
901 // Commented out - currently unused. ICU 2.6, Alan
902 //    //-------------------------------------------------------------------------
903 //    // Alternate Sun Rise/Set
904 //    // See sci.astro FAQ
905 //    // http://www.faqs.org/faqs/astronomy/faq/part3/section-5.html
906 //    //-------------------------------------------------------------------------
907 //
908 //    // Note: This method appears to produce inferior accuracy as
909 //    // compared to getSunRiseSet().
910 //
911 //    /**
912 //     * TODO Make this when the entire class is package-private.
913 //     */
914 //    /*public*/ long getSunRiseSet3(boolean rise) {
915 //
916 //        // Compute day number for 0.0 Jan 2000 epoch
917 //        double d = (double)(time - EPOCH_2000_MS) / DAY_MS;
918 //
919 //        // Now compute the Local Sidereal Time, LST:
920 //        //
921 //        double LST  =  98.9818  +  0.985647352 * d  +  /*UT*15  +  long*/
922 //            fLongitude*RAD_DEG;
923 //        //
924 //        // (east long. positive).  Note that LST is here expressed in degrees,
925 //        // where 15 degrees corresponds to one hour.  Since LST really is an angle,
926 //        // it's convenient to use one unit---degrees---throughout.
927 //
928 //        //    COMPUTING THE SUN'S POSITION
929 //        //    ----------------------------
930 //        //
931 //        // To be able to compute the Sun's rise/set times, you need to be able to
932 //        // compute the Sun's position at any time.  First compute the "day
933 //        // number" d as outlined above, for the desired moment.  Next compute:
934 //        //
935 //        double oblecl = 23.4393 - 3.563E-7 * d;
936 //        //
937 //        double w  =  282.9404  +  4.70935E-5   * d;
938 //        double M  =  356.0470  +  0.9856002585 * d;
939 //        double e  =  0.016709  -  1.151E-9     * d;
940 //        //
941 //        // This is the obliquity of the ecliptic, plus some of the elements of
942 //        // the Sun's apparent orbit (i.e., really the Earth's orbit): w =
943 //        // argument of perihelion, M = mean anomaly, e = eccentricity.
944 //        // Semi-major axis is here assumed to be exactly 1.0 (while not strictly
945 //        // true, this is still an accurate approximation).  Next compute E, the
946 //        // eccentric anomaly:
947 //        //
948 //        double E = M + e*(180/PI) * ::sin(M*DEG_RAD) * ( 1.0 + e*cos(M*DEG_RAD) );
949 //        //
950 //        // where E and M are in degrees.  This is it---no further iterations are
951 //        // needed because we know e has a sufficiently small value.  Next compute
952 //        // the true anomaly, v, and the distance, r:
953 //        //
954 //        /*      r * cos(v)  =  */ double A  =  cos(E*DEG_RAD) - e;
955 //        /*      r * ::sin(v)  =  */ double B  =  ::sqrt(1 - e*e) * ::sin(E*DEG_RAD);
956 //        //
957 //        // and
958 //        //
959 //        //      r  =  sqrt( A*A + B*B )
960 //        double v  =  ::atan2( B, A )*RAD_DEG;
961 //        //
962 //        // The Sun's true longitude, slon, can now be computed:
963 //        //
964 //        double slon  =  v + w;
965 //        //
966 //        // Since the Sun is always at the ecliptic (or at least very very close to
967 //        // it), we can use simplified formulae to convert slon (the Sun's ecliptic
968 //        // longitude) to sRA and sDec (the Sun's RA and Dec):
969 //        //
970 //        //                   ::sin(slon) * cos(oblecl)
971 //        //     tan(sRA)  =  -------------------------
972 //        //            cos(slon)
973 //        //
974 //        //     ::sin(sDec) =  ::sin(oblecl) * ::sin(slon)
975 //        //
976 //        // As was the case when computing az, the Azimuth, if possible use an
977 //        // atan2() function to compute sRA.
978 //
979 //        double sRA = ::atan2(sin(slon*DEG_RAD) * cos(oblecl*DEG_RAD), cos(slon*DEG_RAD))*RAD_DEG;
980 //
981 //        double sin_sDec = ::sin(oblecl*DEG_RAD) * ::sin(slon*DEG_RAD);
982 //        double sDec = ::asin(sin_sDec)*RAD_DEG;
983 //
984 //        //    COMPUTING RISE AND SET TIMES
985 //        //    ----------------------------
986 //        //
987 //        // To compute when an object rises or sets, you must compute when it
988 //        // passes the meridian and the HA of rise/set.  Then the rise time is
989 //        // the meridian time minus HA for rise/set, and the set time is the
990 //        // meridian time plus the HA for rise/set.
991 //        //
992 //        // To find the meridian time, compute the Local Sidereal Time at 0h local
993 //        // time (or 0h UT if you prefer to work in UT) as outlined above---name
994 //        // that quantity LST0.  The Meridian Time, MT, will now be:
995 //        //
996 //        //     MT  =  RA - LST0
997 //        double MT = normalize(sRA - LST, 360);
998 //        //
999 //        // where "RA" is the object's Right Ascension (in degrees!).  If negative,
1000 //        // add 360 deg to MT.  If the object is the Sun, leave the time as it is,
1001 //        // but if it's stellar, multiply MT by 365.2422/366.2422, to convert from
1002 //        // sidereal to solar time.  Now, compute HA for rise/set, name that
1003 //        // quantity HA0:
1004 //        //
1005 //        //                 ::sin(h0)  -  ::sin(lat) * ::sin(Dec)
1006 //        // cos(HA0)  =  ---------------------------------
1007 //        //                      cos(lat) * cos(Dec)
1008 //        //
1009 //        // where h0 is the altitude selected to represent rise/set.  For a purely
1010 //        // mathematical horizon, set h0 = 0 and simplify to:
1011 //        //
1012 //        //    cos(HA0)  =  - tan(lat) * tan(Dec)
1013 //        //
1014 //        // If you want to account for refraction on the atmosphere, set h0 = -35/60
1015 //        // degrees (-35 arc minutes), and if you want to compute the rise/set times
1016 //        // for the Sun's upper limb, set h0 = -50/60 (-50 arc minutes).
1017 //        //
1018 //        double h0 = -50/60 * DEG_RAD;
1019 //
1020 //        double HA0 = ::acos(
1021 //          (sin(h0) - ::sin(fLatitude) * sin_sDec) /
1022 //          (cos(fLatitude) * cos(sDec*DEG_RAD)))*RAD_DEG;
1023 //
1024 //        // When HA0 has been computed, leave it as it is for the Sun but multiply
1025 //        // by 365.2422/366.2422 for stellar objects, to convert from sidereal to
1026 //        // solar time.  Finally compute:
1027 //        //
1028 //        //    Rise time  =  MT - HA0
1029 //        //    Set  time  =  MT + HA0
1030 //        //
1031 //        // convert the times from degrees to hours by dividing by 15.
1032 //        //
1033 //        // If you'd like to check that your calculations are accurate or just
1034 //        // need a quick result, check the USNO's Sun or Moon Rise/Set Table,
1035 //        // <URL:http://aa.usno.navy.mil/AA/data/docs/RS_OneYear.html>.
1036 //
1037 //        double result = MT + (rise ? -HA0 : HA0); // in degrees
1038 //
1039 //        // Find UT midnight on this day
1040 //        long midnight = DAY_MS * (time / DAY_MS);
1041 //
1042 //        return midnight + (long) (result * 3600000 / 15);
1043 //    }
1044 
1045 //-------------------------------------------------------------------------
1046 // The Moon
1047 //-------------------------------------------------------------------------
1048 
1049 #define moonL0  (318.351648 * CalendarAstronomer::PI/180 )   // Mean long. at epoch
1050 #define moonP0 ( 36.340410 * CalendarAstronomer::PI/180 )   // Mean long. of perigee
1051 #define moonN0 ( 318.510107 * CalendarAstronomer::PI/180 )   // Mean long. of node
1052 #define moonI  (   5.145366 * CalendarAstronomer::PI/180 )   // Inclination of orbit
1053 #define moonE  (   0.054900 )            // Eccentricity of orbit
1054 
1055 // These aren't used right now
1056 #define moonA  (   3.84401e5 )           // semi-major axis (km)
1057 #define moonT0 (   0.5181 * CalendarAstronomer::PI/180 )     // Angular size at distance A
1058 #define moonPi (   0.9507 * CalendarAstronomer::PI/180 )     // Parallax at distance A
1059 
1060 /**
1061  * The position of the moon at the time set on this
1062  * object, in equatorial coordinates.
1063  * @internal
1064  * @deprecated ICU 2.4. This class may be removed or modified.
1065  */
getMoonPosition()1066 const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition()
1067 {
1068     //
1069     // See page 142 of "Practial Astronomy with your Calculator",
1070     // by Peter Duffet-Smith, for details on the algorithm.
1071     //
1072     if (moonPositionSet == FALSE) {
1073         // Calculate the solar longitude.  Has the side effect of
1074         // filling in "meanAnomalySun" as well.
1075         getSunLongitude();
1076 
1077         //
1078         // Find the # of days since the epoch of our orbital parameters.
1079         // TODO: Convert the time of day portion into ephemeris time
1080         //
1081         double day = getJulianDay() - JD_EPOCH;       // Days since epoch
1082 
1083         // Calculate the mean longitude and anomaly of the moon, based on
1084         // a circular orbit.  Similar to the corresponding solar calculation.
1085         double meanLongitude = norm2PI(13.1763966*PI/180*day + moonL0);
1086         meanAnomalyMoon = norm2PI(meanLongitude - 0.1114041*PI/180 * day - moonP0);
1087 
1088         //
1089         // Calculate the following corrections:
1090         //  Evection:   the sun's gravity affects the moon's eccentricity
1091         //  Annual Eqn: variation in the effect due to earth-sun distance
1092         //  A3:         correction factor (for ???)
1093         //
1094         double evection = 1.2739*PI/180 * ::sin(2 * (meanLongitude - sunLongitude)
1095             - meanAnomalyMoon);
1096         double annual   = 0.1858*PI/180 * ::sin(meanAnomalySun);
1097         double a3       = 0.3700*PI/180 * ::sin(meanAnomalySun);
1098 
1099         meanAnomalyMoon += evection - annual - a3;
1100 
1101         //
1102         // More correction factors:
1103         //  center  equation of the center correction
1104         //  a4      yet another error correction (???)
1105         //
1106         // TODO: Skip the equation of the center correction and solve Kepler's eqn?
1107         //
1108         double center = 6.2886*PI/180 * ::sin(meanAnomalyMoon);
1109         double a4 =     0.2140*PI/180 * ::sin(2 * meanAnomalyMoon);
1110 
1111         // Now find the moon's corrected longitude
1112         moonLongitude = meanLongitude + evection + center - annual + a4;
1113 
1114         //
1115         // And finally, find the variation, caused by the fact that the sun's
1116         // gravitational pull on the moon varies depending on which side of
1117         // the earth the moon is on
1118         //
1119         double variation = 0.6583*CalendarAstronomer::PI/180 * ::sin(2*(moonLongitude - sunLongitude));
1120 
1121         moonLongitude += variation;
1122 
1123         //
1124         // What we've calculated so far is the moon's longitude in the plane
1125         // of its own orbit.  Now map to the ecliptic to get the latitude
1126         // and longitude.  First we need to find the longitude of the ascending
1127         // node, the position on the ecliptic where it is crossed by the moon's
1128         // orbit as it crosses from the southern to the northern hemisphere.
1129         //
1130         double nodeLongitude = norm2PI(moonN0 - 0.0529539*PI/180 * day);
1131 
1132         nodeLongitude -= 0.16*PI/180 * ::sin(meanAnomalySun);
1133 
1134         double y = ::sin(moonLongitude - nodeLongitude);
1135         double x = cos(moonLongitude - nodeLongitude);
1136 
1137         moonEclipLong = ::atan2(y*cos(moonI), x) + nodeLongitude;
1138         double moonEclipLat = ::asin(y * ::sin(moonI));
1139 
1140         eclipticToEquatorial(moonPosition, moonEclipLong, moonEclipLat);
1141         moonPositionSet = TRUE;
1142     }
1143     return moonPosition;
1144 }
1145 
1146 /**
1147  * The "age" of the moon at the time specified in this object.
1148  * This is really the angle between the
1149  * current ecliptic longitudes of the sun and the moon,
1150  * measured in radians.
1151  *
1152  * @see #getMoonPhase
1153  * @internal
1154  * @deprecated ICU 2.4. This class may be removed or modified.
1155  */
getMoonAge()1156 double CalendarAstronomer::getMoonAge() {
1157     // See page 147 of "Practial Astronomy with your Calculator",
1158     // by Peter Duffet-Smith, for details on the algorithm.
1159     //
1160     // Force the moon's position to be calculated.  We're going to use
1161     // some the intermediate results cached during that calculation.
1162     //
1163     getMoonPosition();
1164 
1165     return norm2PI(moonEclipLong - sunLongitude);
1166 }
1167 
1168 /**
1169  * Calculate the phase of the moon at the time set in this object.
1170  * The returned phase is a <code>double</code> in the range
1171  * <code>0 <= phase < 1</code>, interpreted as follows:
1172  * <ul>
1173  * <li>0.00: New moon
1174  * <li>0.25: First quarter
1175  * <li>0.50: Full moon
1176  * <li>0.75: Last quarter
1177  * </ul>
1178  *
1179  * @see #getMoonAge
1180  * @internal
1181  * @deprecated ICU 2.4. This class may be removed or modified.
1182  */
getMoonPhase()1183 double CalendarAstronomer::getMoonPhase() {
1184     // See page 147 of "Practial Astronomy with your Calculator",
1185     // by Peter Duffet-Smith, for details on the algorithm.
1186     return 0.5 * (1 - cos(getMoonAge()));
1187 }
1188 
1189 /**
1190  * Constant representing a new moon.
1191  * For use with {@link #getMoonTime getMoonTime}
1192  * @internal
1193  * @deprecated ICU 2.4. This class may be removed or modified.
1194  */
NEW_MOON()1195 const CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() {
1196     return  CalendarAstronomer::MoonAge(0);
1197 }
1198 
1199 /**
1200  * Constant representing the moon's first quarter.
1201  * For use with {@link #getMoonTime getMoonTime}
1202  * @internal
1203  * @deprecated ICU 2.4. This class may be removed or modified.
1204  */
1205 /*const CalendarAstronomer::MoonAge CalendarAstronomer::FIRST_QUARTER() {
1206   return   CalendarAstronomer::MoonAge(CalendarAstronomer::PI/2);
1207 }*/
1208 
1209 /**
1210  * Constant representing a full moon.
1211  * For use with {@link #getMoonTime getMoonTime}
1212  * @internal
1213  * @deprecated ICU 2.4. This class may be removed or modified.
1214  */
FULL_MOON()1215 const CalendarAstronomer::MoonAge CalendarAstronomer::FULL_MOON() {
1216     return   CalendarAstronomer::MoonAge(CalendarAstronomer::PI);
1217 }
1218 /**
1219  * Constant representing the moon's last quarter.
1220  * For use with {@link #getMoonTime getMoonTime}
1221  * @internal
1222  * @deprecated ICU 2.4. This class may be removed or modified.
1223  */
1224 
1225 class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc {
1226 public:
1227     virtual ~MoonTimeAngleFunc();
eval(CalendarAstronomer & a)1228     virtual double eval(CalendarAstronomer&a) { return a.getMoonAge(); }
1229 };
1230 
~MoonTimeAngleFunc()1231 MoonTimeAngleFunc::~MoonTimeAngleFunc() {}
1232 
1233 /*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() {
1234   return  CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2);
1235 }*/
1236 
1237 /**
1238  * Find the next or previous time at which the Moon's ecliptic
1239  * longitude will have the desired value.
1240  * <p>
1241  * @param desired   The desired longitude.
1242  * @param next      <tt>true</tt> if the next occurrance of the phase
1243  *                  is desired, <tt>false</tt> for the previous occurrance.
1244  * @internal
1245  * @deprecated ICU 2.4. This class may be removed or modified.
1246  */
getMoonTime(double desired,UBool next)1247 UDate CalendarAstronomer::getMoonTime(double desired, UBool next)
1248 {
1249     MoonTimeAngleFunc func;
1250     return timeOfAngle( func,
1251                         desired,
1252                         SYNODIC_MONTH,
1253                         MINUTE_MS,
1254                         next);
1255 }
1256 
1257 /**
1258  * Find the next or previous time at which the moon will be in the
1259  * desired phase.
1260  * <p>
1261  * @param desired   The desired phase of the moon.
1262  * @param next      <tt>true</tt> if the next occurrance of the phase
1263  *                  is desired, <tt>false</tt> for the previous occurrance.
1264  * @internal
1265  * @deprecated ICU 2.4. This class may be removed or modified.
1266  */
getMoonTime(const CalendarAstronomer::MoonAge & desired,UBool next)1267 UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) {
1268     return getMoonTime(desired.value, next);
1269 }
1270 
1271 class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
1272 public:
1273     virtual ~MoonRiseSetCoordFunc();
eval(CalendarAstronomer::Equatorial & result,CalendarAstronomer & a)1274     virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { result = a.getMoonPosition(); }
1275 };
1276 
~MoonRiseSetCoordFunc()1277 MoonRiseSetCoordFunc::~MoonRiseSetCoordFunc() {}
1278 
1279 /**
1280  * Returns the time (GMT) of sunrise or sunset on the local date to which
1281  * this calendar is currently set.
1282  * @internal
1283  * @deprecated ICU 2.4. This class may be removed or modified.
1284  */
getMoonRiseSet(UBool rise)1285 UDate CalendarAstronomer::getMoonRiseSet(UBool rise)
1286 {
1287     MoonRiseSetCoordFunc func;
1288     return riseOrSet(func,
1289                      rise,
1290                      .533 * DEG_RAD,        // Angular Diameter
1291                      34 /60.0 * DEG_RAD,    // Refraction correction
1292                      MINUTE_MS);            // Desired accuracy
1293 }
1294 
1295 //-------------------------------------------------------------------------
1296 // Interpolation methods for finding the time at which a given event occurs
1297 //-------------------------------------------------------------------------
1298 
timeOfAngle(AngleFunc & func,double desired,double periodDays,double epsilon,UBool next)1299 UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired,
1300                                       double periodDays, double epsilon, UBool next)
1301 {
1302     // Find the value of the function at the current time
1303     double lastAngle = func.eval(*this);
1304 
1305     // Find out how far we are from the desired angle
1306     double deltaAngle = norm2PI(desired - lastAngle) ;
1307 
1308     // Using the average period, estimate the next (or previous) time at
1309     // which the desired angle occurs.
1310     double deltaT =  (deltaAngle + (next ? 0.0 : - CalendarAstronomer_PI2 )) * (periodDays*DAY_MS) / CalendarAstronomer_PI2;
1311 
1312     double lastDeltaT = deltaT; // Liu
1313     UDate startTime = fTime; // Liu
1314 
1315     setTime(fTime + uprv_ceil(deltaT));
1316 
1317     // Now iterate until we get the error below epsilon.  Throughout
1318     // this loop we use normPI to get values in the range -Pi to Pi,
1319     // since we're using them as correction factors rather than absolute angles.
1320     do {
1321         // Evaluate the function at the time we've estimated
1322         double angle = func.eval(*this);
1323 
1324         // Find the # of milliseconds per radian at this point on the curve
1325         double factor = uprv_fabs(deltaT / normPI(angle-lastAngle));
1326 
1327         // Correct the time estimate based on how far off the angle is
1328         deltaT = normPI(desired - angle) * factor;
1329 
1330         // HACK:
1331         //
1332         // If abs(deltaT) begins to diverge we need to quit this loop.
1333         // This only appears to happen when attempting to locate, for
1334         // example, a new moon on the day of the new moon.  E.g.:
1335         //
1336         // This result is correct:
1337         // newMoon(7508(Mon Jul 23 00:00:00 CST 1990,false))=
1338         //   Sun Jul 22 10:57:41 CST 1990
1339         //
1340         // But attempting to make the same call a day earlier causes deltaT
1341         // to diverge:
1342         // CalendarAstronomer.timeOfAngle() diverging: 1.348508727575625E9 ->
1343         //   1.3649828540224032E9
1344         // newMoon(7507(Sun Jul 22 00:00:00 CST 1990,false))=
1345         //   Sun Jul 08 13:56:15 CST 1990
1346         //
1347         // As a temporary solution, we catch this specific condition and
1348         // adjust our start time by one eighth period days (either forward
1349         // or backward) and try again.
1350         // Liu 11/9/00
1351         if (uprv_fabs(deltaT) > uprv_fabs(lastDeltaT)) {
1352             double delta = uprv_ceil (periodDays * DAY_MS / 8.0);
1353             setTime(startTime + (next ? delta : -delta));
1354             return timeOfAngle(func, desired, periodDays, epsilon, next);
1355         }
1356 
1357         lastDeltaT = deltaT;
1358         lastAngle = angle;
1359 
1360         setTime(fTime + uprv_ceil(deltaT));
1361     }
1362     while (uprv_fabs(deltaT) > epsilon);
1363 
1364     return fTime;
1365 }
1366 
riseOrSet(CoordFunc & func,UBool rise,double diameter,double refraction,double epsilon)1367 UDate CalendarAstronomer::riseOrSet(CoordFunc& func, UBool rise,
1368                                     double diameter, double refraction,
1369                                     double epsilon)
1370 {
1371     Equatorial pos;
1372     double      tanL   = ::tan(fLatitude);
1373     double     deltaT = 0;
1374     int32_t         count = 0;
1375 
1376     //
1377     // Calculate the object's position at the current time, then use that
1378     // position to calculate the time of rising or setting.  The position
1379     // will be different at that time, so iterate until the error is allowable.
1380     //
1381     U_DEBUG_ASTRO_MSG(("setup rise=%s, dia=%.3lf, ref=%.3lf, eps=%.3lf\n",
1382         rise?"T":"F", diameter, refraction, epsilon));
1383     do {
1384         // See "Practical Astronomy With Your Calculator, section 33.
1385         func.eval(pos, *this);
1386         double angle = ::acos(-tanL * ::tan(pos.declination));
1387         double lst = ((rise ? CalendarAstronomer_PI2-angle : angle) + pos.ascension ) * 24 / CalendarAstronomer_PI2;
1388 
1389         // Convert from LST to Universal Time.
1390         UDate newTime = lstToUT( lst );
1391 
1392         deltaT = newTime - fTime;
1393         setTime(newTime);
1394         U_DEBUG_ASTRO_MSG(("%d] dT=%.3lf, angle=%.3lf, lst=%.3lf,   A=%.3lf/D=%.3lf\n",
1395             count, deltaT, angle, lst, pos.ascension, pos.declination));
1396     }
1397     while (++ count < 5 && uprv_fabs(deltaT) > epsilon);
1398 
1399     // Calculate the correction due to refraction and the object's angular diameter
1400     double cosD  = ::cos(pos.declination);
1401     double psi   = ::acos(sin(fLatitude) / cosD);
1402     double x     = diameter / 2 + refraction;
1403     double y     = ::asin(sin(x) / ::sin(psi));
1404     long  delta  = (long)((240 * y * RAD_DEG / cosD)*SECOND_MS);
1405 
1406     return fTime + (rise ? -delta : delta);
1407 }
1408 											   /**
1409  * Return the obliquity of the ecliptic (the angle between the ecliptic
1410  * and the earth's equator) at the current time.  This varies due to
1411  * the precession of the earth's axis.
1412  *
1413  * @return  the obliquity of the ecliptic relative to the equator,
1414  *          measured in radians.
1415  */
eclipticObliquity()1416 double CalendarAstronomer::eclipticObliquity() {
1417     if (isINVALID(eclipObliquity)) {
1418         const double epoch = 2451545.0;     // 2000 AD, January 1.5
1419 
1420         double T = (getJulianDay() - epoch) / 36525;
1421 
1422         eclipObliquity = 23.439292
1423             - 46.815/3600 * T
1424             - 0.0006/3600 * T*T
1425             + 0.00181/3600 * T*T*T;
1426 
1427         eclipObliquity *= DEG_RAD;
1428     }
1429     return eclipObliquity;
1430 }
1431 
1432 
1433 //-------------------------------------------------------------------------
1434 // Private data
1435 //-------------------------------------------------------------------------
clearCache()1436 void CalendarAstronomer::clearCache() {
1437     const double INVALID = uprv_getNaN();
1438 
1439     julianDay       = INVALID;
1440     julianCentury   = INVALID;
1441     sunLongitude    = INVALID;
1442     meanAnomalySun  = INVALID;
1443     moonLongitude   = INVALID;
1444     moonEclipLong   = INVALID;
1445     meanAnomalyMoon = INVALID;
1446     eclipObliquity  = INVALID;
1447     siderealTime    = INVALID;
1448     siderealT0      = INVALID;
1449     moonPositionSet = FALSE;
1450 }
1451 
1452 //private static void out(String s) {
1453 //    System.out.println(s);
1454 //}
1455 
1456 //private static String deg(double rad) {
1457 //    return Double.toString(rad * RAD_DEG);
1458 //}
1459 
1460 //private static String hours(long ms) {
1461 //    return Double.toString((double)ms / HOUR_MS) + " hours";
1462 //}
1463 
1464 /**
1465  * @internal
1466  * @deprecated ICU 2.4. This class may be removed or modified.
1467  */
1468 /*UDate CalendarAstronomer::local(UDate localMillis) {
1469   // TODO - srl ?
1470   TimeZone *tz = TimeZone::createDefault();
1471   int32_t rawOffset;
1472   int32_t dstOffset;
1473   UErrorCode status = U_ZERO_ERROR;
1474   tz->getOffset(localMillis, TRUE, rawOffset, dstOffset, status);
1475   delete tz;
1476   return localMillis - rawOffset;
1477 }*/
1478 
1479 // Debugging functions
toString() const1480 UnicodeString CalendarAstronomer::Ecliptic::toString() const
1481 {
1482 #ifdef U_DEBUG_ASTRO
1483     char tmp[800];
1484     sprintf(tmp, "[%.5f,%.5f]", longitude*RAD_DEG, latitude*RAD_DEG);
1485     return UnicodeString(tmp, "");
1486 #else
1487     return UnicodeString();
1488 #endif
1489 }
1490 
toString() const1491 UnicodeString CalendarAstronomer::Equatorial::toString() const
1492 {
1493 #ifdef U_DEBUG_ASTRO
1494     char tmp[400];
1495     sprintf(tmp, "%f,%f",
1496         (ascension*RAD_DEG), (declination*RAD_DEG));
1497     return UnicodeString(tmp, "");
1498 #else
1499     return UnicodeString();
1500 #endif
1501 }
1502 
toString() const1503 UnicodeString CalendarAstronomer::Horizon::toString() const
1504 {
1505 #ifdef U_DEBUG_ASTRO
1506     char tmp[800];
1507     sprintf(tmp, "[%.5f,%.5f]", altitude*RAD_DEG, azimuth*RAD_DEG);
1508     return UnicodeString(tmp, "");
1509 #else
1510     return UnicodeString();
1511 #endif
1512 }
1513 
1514 
1515 //  static private String radToHms(double angle) {
1516 //    int hrs = (int) (angle*RAD_HOUR);
1517 //    int min = (int)((angle*RAD_HOUR - hrs) * 60);
1518 //    int sec = (int)((angle*RAD_HOUR - hrs - min/60.0) * 3600);
1519 
1520 //    return Integer.toString(hrs) + "h" + min + "m" + sec + "s";
1521 //  }
1522 
1523 //  static private String radToDms(double angle) {
1524 //    int deg = (int) (angle*RAD_DEG);
1525 //    int min = (int)((angle*RAD_DEG - deg) * 60);
1526 //    int sec = (int)((angle*RAD_DEG - deg - min/60.0) * 3600);
1527 
1528 //    return Integer.toString(deg) + "\u00b0" + min + "'" + sec + "\"";
1529 //  }
1530 
1531 // =============== Calendar Cache ================
1532 
createCache(CalendarCache ** cache,UErrorCode & status)1533 void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) {
1534     ucln_i18n_registerCleanup(UCLN_I18N_ASTRO_CALENDAR, calendar_astro_cleanup);
1535     if(cache == NULL) {
1536         status = U_MEMORY_ALLOCATION_ERROR;
1537     } else {
1538         *cache = new CalendarCache(32, status);
1539         if(U_FAILURE(status)) {
1540             delete *cache;
1541             *cache = NULL;
1542         }
1543     }
1544 }
1545 
get(CalendarCache ** cache,int32_t key,UErrorCode & status)1546 int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) {
1547     int32_t res;
1548 
1549     if(U_FAILURE(status)) {
1550         return 0;
1551     }
1552     umtx_lock(&ccLock);
1553 
1554     if(*cache == NULL) {
1555         createCache(cache, status);
1556         if(U_FAILURE(status)) {
1557             umtx_unlock(&ccLock);
1558             return 0;
1559         }
1560     }
1561 
1562     res = uhash_igeti((*cache)->fTable, key);
1563     U_DEBUG_ASTRO_MSG(("%p: GET: [%d] == %d\n", (*cache)->fTable, key, res));
1564 
1565     umtx_unlock(&ccLock);
1566     return res;
1567 }
1568 
put(CalendarCache ** cache,int32_t key,int32_t value,UErrorCode & status)1569 void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) {
1570     if(U_FAILURE(status)) {
1571         return;
1572     }
1573     umtx_lock(&ccLock);
1574 
1575     if(*cache == NULL) {
1576         createCache(cache, status);
1577         if(U_FAILURE(status)) {
1578             umtx_unlock(&ccLock);
1579             return;
1580         }
1581     }
1582 
1583     uhash_iputi((*cache)->fTable, key, value, &status);
1584     U_DEBUG_ASTRO_MSG(("%p: PUT: [%d] := %d\n", (*cache)->fTable, key, value));
1585 
1586     umtx_unlock(&ccLock);
1587 }
1588 
CalendarCache(int32_t size,UErrorCode & status)1589 CalendarCache::CalendarCache(int32_t size, UErrorCode &status) {
1590     fTable = uhash_openSize(uhash_hashLong, uhash_compareLong, NULL, size, &status);
1591     U_DEBUG_ASTRO_MSG(("%p: Opening.\n", fTable));
1592 }
1593 
~CalendarCache()1594 CalendarCache::~CalendarCache() {
1595     if(fTable != NULL) {
1596         U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable));
1597         uhash_close(fTable);
1598     }
1599 }
1600 
1601 U_NAMESPACE_END
1602 
1603 #endif //  !UCONFIG_NO_FORMATTING
1604