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
31static void debug_astro_loc(const char *f, int32_t l)
32{
33 fprintf(stderr, "%s:%d: ", f, l);
34}
35
36static 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"
45static 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
64static inline UBool isINVALID(double d) {
65 return(uprv_isNaN(d));
66}
67
68static icu::UMutex ccLock;
69
70U_CDECL_BEGIN
71static UBool calendar_astro_cleanup(void) {
72 return TRUE;
73}
74U_CDECL_END
75
76U_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 */
105const 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
203const 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 */
214inline 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 */
223inline 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 */
230inline 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 */
244CalendarAstronomer::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 */
255CalendarAstronomer::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 */
274CalendarAstronomer::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
282CalendarAstronomer::~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 */
302void 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 */
323void 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 */
339UDate 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 */
353double 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 */
368double 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 */
380double 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
392double 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 */
407double 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 */
420double 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 */
446CalendarAstronomer::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 */
461CalendarAstronomer::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 */
491CalendarAstronomer::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 */
500CalendarAstronomer::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 */
596static 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 */
624double 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 */
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 */
666CalendarAstronomer::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 */
689double 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 */
711double CalendarAstronomer::WINTER_SOLSTICE() {
712 return ((CalendarAstronomer::PI*3)/2);
713}
714
715CalendarAstronomer::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 */
723class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc {
724public:
725 virtual ~SunTimeAngleFunc();
726 virtual double eval(CalendarAstronomer& a) { return a.getSunLongitude(); }
727};
728
729SunTimeAngleFunc::~SunTimeAngleFunc() {}
730
731UDate 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
741CalendarAstronomer::CoordFunc::~CoordFunc() {}
742
743class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
744public:
745 virtual ~RiseSetCoordFunc();
746 virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { a.getSunPosition(result); }
747};
748
749RiseSetCoordFunc::~RiseSetCoordFunc() {}
750
751UDate 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 */
1066const 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 */
1156double 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 */
1183double 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 */
1195const 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 */
1215const 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
1225class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc {
1226public:
1227 virtual ~MoonTimeAngleFunc();
1228 virtual double eval(CalendarAstronomer&a) { return a.getMoonAge(); }
1229};
1230
1231MoonTimeAngleFunc::~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 */
1247UDate 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 */
1267UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) {
1268 return getMoonTime(desired.value, next);
1269}
1270
1271class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
1272public:
1273 virtual ~MoonRiseSetCoordFunc();
1274 virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { result = a.getMoonPosition(); }
1275};
1276
1277MoonRiseSetCoordFunc::~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 */
1285UDate 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
1299UDate 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
1367UDate 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 */
1416double 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//-------------------------------------------------------------------------
1436void 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
1480UnicodeString 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
1491UnicodeString 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
1503UnicodeString 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
1533void 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
1546int32_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
1569void 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
1589CalendarCache::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
1594CalendarCache::~CalendarCache() {
1595 if(fTable != NULL) {
1596 U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable));
1597 uhash_close(fTable);
1598 }
1599}
1600
1601U_NAMESPACE_END
1602
1603#endif // !UCONFIG_NO_FORMATTING
1604