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1 /************************************************************************
2 * Copyright (C) 1996-2012, International Business Machines Corporation
3 * and others. All Rights Reserved.
4 ************************************************************************
5 * 2003-nov-07 srl Port from Java
6 */
7
8 #include "astro.h"
9
10 #if !UCONFIG_NO_FORMATTING
11
12 #include "unicode/calendar.h"
13 #include <math.h>
14 #include <float.h>
15 #include "unicode/putil.h"
16 #include "uhash.h"
17 #include "umutex.h"
18 #include "ucln_in.h"
19 #include "putilimp.h"
20 #include <stdio.h> // for toString()
21
22 #if defined (PI)
23 #undef PI
24 #endif
25
26 #ifdef U_DEBUG_ASTRO
27 # include "uresimp.h" // for debugging
28
29 static void debug_astro_loc(const char *f, int32_t l)
30 {
31 fprintf(stderr, "%s:%d: ", f, l);
32 }
33
34 static void debug_astro_msg(const char *pat, ...)
35 {
36 va_list ap;
37 va_start(ap, pat);
38 vfprintf(stderr, pat, ap);
39 fflush(stderr);
40 }
41 #include "unicode/datefmt.h"
42 #include "unicode/ustring.h"
43 static const char * debug_astro_date(UDate d) {
44 static char gStrBuf[1024];
45 static DateFormat *df = NULL;
46 if(df == NULL) {
47 df = DateFormat::createDateTimeInstance(DateFormat::MEDIUM, DateFormat::MEDIUM, Locale::getUS());
48 df->adoptTimeZone(TimeZone::getGMT()->clone());
49 }
50 UnicodeString str;
51 df->format(d,str);
52 u_austrncpy(gStrBuf,str.getTerminatedBuffer(),sizeof(gStrBuf)-1);
53 return gStrBuf;
54 }
55
56 // must use double parens, i.e.: U_DEBUG_ASTRO_MSG(("four is: %d",4));
57 #define U_DEBUG_ASTRO_MSG(x) {debug_astro_loc(__FILE__,__LINE__);debug_astro_msg x;}
58 #else
59 #define U_DEBUG_ASTRO_MSG(x)
60 #endif
61
62 static inline UBool isINVALID(double d) {
63 return(uprv_isNaN(d));
64 }
65
66 static UMutex ccLock = U_MUTEX_INITIALIZER;
67
68 U_CDECL_BEGIN
69 static UBool calendar_astro_cleanup(void) {
70 return TRUE;
71 }
72 U_CDECL_END
73
74 U_NAMESPACE_BEGIN
75
76 /**
77 * The number of standard hours in one sidereal day.
78 * Approximately 24.93.
79 * @internal
80 * @deprecated ICU 2.4. This class may be removed or modified.
81 */
82 #define SIDEREAL_DAY (23.93446960027)
83
84 /**
85 * The number of sidereal hours in one mean solar day.
86 * Approximately 24.07.
87 * @internal
88 * @deprecated ICU 2.4. This class may be removed or modified.
89 */
90 #define SOLAR_DAY (24.065709816)
91
92 /**
93 * The average number of solar days from one new moon to the next. This is the time
94 * it takes for the moon to return the same ecliptic longitude as the sun.
95 * It is longer than the sidereal month because the sun's longitude increases
96 * during the year due to the revolution of the earth around the sun.
97 * Approximately 29.53.
98 *
99 * @see #SIDEREAL_MONTH
100 * @internal
101 * @deprecated ICU 2.4. This class may be removed or modified.
102 */
103 const double CalendarAstronomer::SYNODIC_MONTH = 29.530588853;
104
105 /**
106 * The average number of days it takes
107 * for the moon to return to the same ecliptic longitude relative to the
108 * stellar background. This is referred to as the sidereal month.
109 * It is shorter than the synodic month due to
110 * the revolution of the earth around the sun.
111 * Approximately 27.32.
112 *
113 * @see #SYNODIC_MONTH
114 * @internal
115 * @deprecated ICU 2.4. This class may be removed or modified.
116 */
117 #define SIDEREAL_MONTH 27.32166
118
119 /**
120 * The average number number of days between successive vernal equinoxes.
121 * Due to the precession of the earth's
122 * axis, this is not precisely the same as the sidereal year.
123 * Approximately 365.24
124 *
125 * @see #SIDEREAL_YEAR
126 * @internal
127 * @deprecated ICU 2.4. This class may be removed or modified.
128 */
129 #define TROPICAL_YEAR 365.242191
130
131 /**
132 * The average number of days it takes
133 * for the sun to return to the same position against the fixed stellar
134 * background. This is the duration of one orbit of the earth about the sun
135 * as it would appear to an outside observer.
136 * Due to the precession of the earth's
137 * axis, this is not precisely the same as the tropical year.
138 * Approximately 365.25.
139 *
140 * @see #TROPICAL_YEAR
141 * @internal
142 * @deprecated ICU 2.4. This class may be removed or modified.
143 */
144 #define SIDEREAL_YEAR 365.25636
145
146 //-------------------------------------------------------------------------
147 // Time-related constants
148 //-------------------------------------------------------------------------
149
150 /**
151 * The number of milliseconds in one second.
152 * @internal
153 * @deprecated ICU 2.4. This class may be removed or modified.
154 */
155 #define SECOND_MS U_MILLIS_PER_SECOND
156
157 /**
158 * The number of milliseconds in one minute.
159 * @internal
160 * @deprecated ICU 2.4. This class may be removed or modified.
161 */
162 #define MINUTE_MS U_MILLIS_PER_MINUTE
163
164 /**
165 * The number of milliseconds in one hour.
166 * @internal
167 * @deprecated ICU 2.4. This class may be removed or modified.
168 */
169 #define HOUR_MS U_MILLIS_PER_HOUR
170
171 /**
172 * The number of milliseconds in one day.
173 * @internal
174 * @deprecated ICU 2.4. This class may be removed or modified.
175 */
176 #define DAY_MS U_MILLIS_PER_DAY
177
178 /**
179 * The start of the julian day numbering scheme used by astronomers, which
180 * is 1/1/4713 BC (Julian), 12:00 GMT. This is given as the number of milliseconds
181 * since 1/1/1970 AD (Gregorian), a negative number.
182 * Note that julian day numbers and
183 * the Julian calendar are <em>not</em> the same thing. Also note that
184 * julian days start at <em>noon</em>, not midnight.
185 * @internal
186 * @deprecated ICU 2.4. This class may be removed or modified.
187 */
188 #define JULIAN_EPOCH_MS -210866760000000.0
189
190
191 /**
192 * Milliseconds value for 0.0 January 2000 AD.
193 */
194 #define EPOCH_2000_MS 946598400000.0
195
196 //-------------------------------------------------------------------------
197 // Assorted private data used for conversions
198 //-------------------------------------------------------------------------
199
200 // My own copies of these so compilers are more likely to optimize them away
201 const double CalendarAstronomer::PI = 3.14159265358979323846;
202
203 #define CalendarAstronomer_PI2 (CalendarAstronomer::PI*2.0)
204 #define RAD_HOUR ( 12 / CalendarAstronomer::PI ) // radians -> hours
205 #define DEG_RAD ( CalendarAstronomer::PI / 180 ) // degrees -> radians
206 #define RAD_DEG ( 180 / CalendarAstronomer::PI ) // radians -> degrees
207
208 /***
209 * Given 'value', add or subtract 'range' until 0 <= 'value' < range.
210 * The modulus operator.
211 */
212 inline static double normalize(double value, double range) {
213 return value - range * ClockMath::floorDivide(value, range);
214 }
215
216 /**
217 * Normalize an angle so that it's in the range 0 - 2pi.
218 * For positive angles this is just (angle % 2pi), but the Java
219 * mod operator doesn't work that way for negative numbers....
220 */
221 inline static double norm2PI(double angle) {
222 return normalize(angle, CalendarAstronomer::PI * 2.0);
223 }
224
225 /**
226 * Normalize an angle into the range -PI - PI
227 */
228 inline static double normPI(double angle) {
229 return normalize(angle + CalendarAstronomer::PI, CalendarAstronomer::PI * 2.0) - CalendarAstronomer::PI;
230 }
231
232 //-------------------------------------------------------------------------
233 // Constructors
234 //-------------------------------------------------------------------------
235
236 /**
237 * Construct a new <code>CalendarAstronomer</code> object that is initialized to
238 * the current date and time.
239 * @internal
240 * @deprecated ICU 2.4. This class may be removed or modified.
241 */
242 CalendarAstronomer::CalendarAstronomer():
243 fTime(Calendar::getNow()), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
244 clearCache();
245 }
246
247 /**
248 * Construct a new <code>CalendarAstronomer</code> object that is initialized to
249 * the specified date and time.
250 * @internal
251 * @deprecated ICU 2.4. This class may be removed or modified.
252 */
253 CalendarAstronomer::CalendarAstronomer(UDate d): fTime(d), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
254 clearCache();
255 }
256
257 /**
258 * Construct a new <code>CalendarAstronomer</code> object with the given
259 * latitude and longitude. The object's time is set to the current
260 * date and time.
261 * <p>
262 * @param longitude The desired longitude, in <em>degrees</em> east of
263 * the Greenwich meridian.
264 *
265 * @param latitude The desired latitude, in <em>degrees</em>. Positive
266 * values signify North, negative South.
267 *
268 * @see java.util.Date#getTime()
269 * @internal
270 * @deprecated ICU 2.4. This class may be removed or modified.
271 */
272 CalendarAstronomer::CalendarAstronomer(double longitude, double latitude) :
273 fTime(Calendar::getNow()), moonPosition(0,0), moonPositionSet(FALSE) {
274 fLongitude = normPI(longitude * (double)DEG_RAD);
275 fLatitude = normPI(latitude * (double)DEG_RAD);
276 fGmtOffset = (double)(fLongitude * 24. * (double)HOUR_MS / (double)CalendarAstronomer_PI2);
277 clearCache();
278 }
279
280 CalendarAstronomer::~CalendarAstronomer()
281 {
282 }
283
284 //-------------------------------------------------------------------------
285 // Time and date getters and setters
286 //-------------------------------------------------------------------------
287
288 /**
289 * Set the current date and time of this <code>CalendarAstronomer</code> object. All
290 * astronomical calculations are performed based on this time setting.
291 *
292 * @param aTime the date and time, expressed as the number of milliseconds since
293 * 1/1/1970 0:00 GMT (Gregorian).
294 *
295 * @see #setDate
296 * @see #getTime
297 * @internal
298 * @deprecated ICU 2.4. This class may be removed or modified.
299 */
300 void CalendarAstronomer::setTime(UDate aTime) {
301 fTime = aTime;
302 U_DEBUG_ASTRO_MSG(("setTime(%.1lf, %sL)\n", aTime, debug_astro_date(aTime+fGmtOffset)));
303 clearCache();
304 }
305
306 /**
307 * Set the current date and time of this <code>CalendarAstronomer</code> object. All
308 * astronomical calculations are performed based on this time setting.
309 *
310 * @param jdn the desired time, expressed as a "julian day number",
311 * which is the number of elapsed days since
312 * 1/1/4713 BC (Julian), 12:00 GMT. Note that julian day
313 * numbers start at <em>noon</em>. To get the jdn for
314 * the corresponding midnight, subtract 0.5.
315 *
316 * @see #getJulianDay
317 * @see #JULIAN_EPOCH_MS
318 * @internal
319 * @deprecated ICU 2.4. This class may be removed or modified.
320 */
321 void CalendarAstronomer::setJulianDay(double jdn) {
322 fTime = (double)(jdn * DAY_MS) + JULIAN_EPOCH_MS;
323 clearCache();
324 julianDay = jdn;
325 }
326
327 /**
328 * Get the current time of this <code>CalendarAstronomer</code> object,
329 * represented as the number of milliseconds since
330 * 1/1/1970 AD 0:00 GMT (Gregorian).
331 *
332 * @see #setTime
333 * @see #getDate
334 * @internal
335 * @deprecated ICU 2.4. This class may be removed or modified.
336 */
337 UDate CalendarAstronomer::getTime() {
338 return fTime;
339 }
340
341 /**
342 * Get the current time of this <code>CalendarAstronomer</code> object,
343 * expressed as a "julian day number", which is the number of elapsed
344 * days since 1/1/4713 BC (Julian), 12:00 GMT.
345 *
346 * @see #setJulianDay
347 * @see #JULIAN_EPOCH_MS
348 * @internal
349 * @deprecated ICU 2.4. This class may be removed or modified.
350 */
351 double CalendarAstronomer::getJulianDay() {
352 if (isINVALID(julianDay)) {
353 julianDay = (fTime - (double)JULIAN_EPOCH_MS) / (double)DAY_MS;
354 }
355 return julianDay;
356 }
357
358 /**
359 * Return this object's time expressed in julian centuries:
360 * the number of centuries after 1/1/1900 AD, 12:00 GMT
361 *
362 * @see #getJulianDay
363 * @internal
364 * @deprecated ICU 2.4. This class may be removed or modified.
365 */
366 double CalendarAstronomer::getJulianCentury() {
367 if (isINVALID(julianCentury)) {
368 julianCentury = (getJulianDay() - 2415020.0) / 36525.0;
369 }
370 return julianCentury;
371 }
372
373 /**
374 * Returns the current Greenwich sidereal time, measured in hours
375 * @internal
376 * @deprecated ICU 2.4. This class may be removed or modified.
377 */
378 double CalendarAstronomer::getGreenwichSidereal() {
379 if (isINVALID(siderealTime)) {
380 // See page 86 of "Practial Astronomy with your Calculator",
381 // by Peter Duffet-Smith, for details on the algorithm.
382
383 double UT = normalize(fTime/(double)HOUR_MS, 24.);
384
385 siderealTime = normalize(getSiderealOffset() + UT*1.002737909, 24.);
386 }
387 return siderealTime;
388 }
389
390 double CalendarAstronomer::getSiderealOffset() {
391 if (isINVALID(siderealT0)) {
392 double JD = uprv_floor(getJulianDay() - 0.5) + 0.5;
393 double S = JD - 2451545.0;
394 double T = S / 36525.0;
395 siderealT0 = normalize(6.697374558 + 2400.051336*T + 0.000025862*T*T, 24);
396 }
397 return siderealT0;
398 }
399
400 /**
401 * Returns the current local sidereal time, measured in hours
402 * @internal
403 * @deprecated ICU 2.4. This class may be removed or modified.
404 */
405 double CalendarAstronomer::getLocalSidereal() {
406 return normalize(getGreenwichSidereal() + (fGmtOffset/(double)HOUR_MS), 24.);
407 }
408
409 /**
410 * Converts local sidereal time to Universal Time.
411 *
412 * @param lst The Local Sidereal Time, in hours since sidereal midnight
413 * on this object's current date.
414 *
415 * @return The corresponding Universal Time, in milliseconds since
416 * 1 Jan 1970, GMT.
417 */
418 double CalendarAstronomer::lstToUT(double lst) {
419 // Convert to local mean time
420 double lt = normalize((lst - getSiderealOffset()) * 0.9972695663, 24);
421
422 // Then find local midnight on this day
423 double base = (DAY_MS * ClockMath::floorDivide(fTime + fGmtOffset,(double)DAY_MS)) - fGmtOffset;
424
425 //out(" lt =" + lt + " hours");
426 //out(" base=" + new Date(base));
427
428 return base + (long)(lt * HOUR_MS);
429 }
430
431
432 //-------------------------------------------------------------------------
433 // Coordinate transformations, all based on the current time of this object
434 //-------------------------------------------------------------------------
435
436 /**
437 * Convert from ecliptic to equatorial coordinates.
438 *
439 * @param ecliptic A point in the sky in ecliptic coordinates.
440 * @return The corresponding point in equatorial coordinates.
441 * @internal
442 * @deprecated ICU 2.4. This class may be removed or modified.
443 */
444 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, const CalendarAstronomer::Ecliptic& ecliptic)
445 {
446 return eclipticToEquatorial(result, ecliptic.longitude, ecliptic.latitude);
447 }
448
449 /**
450 * Convert from ecliptic to equatorial coordinates.
451 *
452 * @param eclipLong The ecliptic longitude
453 * @param eclipLat The ecliptic latitude
454 *
455 * @return The corresponding point in equatorial coordinates.
456 * @internal
457 * @deprecated ICU 2.4. This class may be removed or modified.
458 */
459 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat)
460 {
461 // See page 42 of "Practial Astronomy with your Calculator",
462 // by Peter Duffet-Smith, for details on the algorithm.
463
464 double obliq = eclipticObliquity();
465 double sinE = ::sin(obliq);
466 double cosE = cos(obliq);
467
468 double sinL = ::sin(eclipLong);
469 double cosL = cos(eclipLong);
470
471 double sinB = ::sin(eclipLat);
472 double cosB = cos(eclipLat);
473 double tanB = tan(eclipLat);
474
475 result.set(atan2(sinL*cosE - tanB*sinE, cosL),
476 asin(sinB*cosE + cosB*sinE*sinL) );
477 return result;
478 }
479
480 /**
481 * Convert from ecliptic longitude to equatorial coordinates.
482 *
483 * @param eclipLong The ecliptic longitude
484 *
485 * @return The corresponding point in equatorial coordinates.
486 * @internal
487 * @deprecated ICU 2.4. This class may be removed or modified.
488 */
489 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong)
490 {
491 return eclipticToEquatorial(result, eclipLong, 0); // TODO: optimize
492 }
493
494 /**
495 * @internal
496 * @deprecated ICU 2.4. This class may be removed or modified.
497 */
498 CalendarAstronomer::Horizon& CalendarAstronomer::eclipticToHorizon(CalendarAstronomer::Horizon& result, double eclipLong)
499 {
500 Equatorial equatorial;
501 eclipticToEquatorial(equatorial, eclipLong);
502
503 double H = getLocalSidereal()*CalendarAstronomer::PI/12 - equatorial.ascension; // Hour-angle
504
505 double sinH = ::sin(H);
506 double cosH = cos(H);
507 double sinD = ::sin(equatorial.declination);
508 double cosD = cos(equatorial.declination);
509 double sinL = ::sin(fLatitude);
510 double cosL = cos(fLatitude);
511
512 double altitude = asin(sinD*sinL + cosD*cosL*cosH);
513 double azimuth = atan2(-cosD*cosL*sinH, sinD - sinL * ::sin(altitude));
514
515 result.set(azimuth, altitude);
516 return result;
517 }
518
519
520 //-------------------------------------------------------------------------
521 // The Sun
522 //-------------------------------------------------------------------------
523
524 //
525 // Parameters of the Sun's orbit as of the epoch Jan 0.0 1990
526 // Angles are in radians (after multiplying by CalendarAstronomer::PI/180)
527 //
528 #define JD_EPOCH 2447891.5 // Julian day of epoch
529
530 #define SUN_ETA_G (279.403303 * CalendarAstronomer::PI/180) // Ecliptic longitude at epoch
531 #define SUN_OMEGA_G (282.768422 * CalendarAstronomer::PI/180) // Ecliptic longitude of perigee
532 #define SUN_E 0.016713 // Eccentricity of orbit
533 //double sunR0 1.495585e8 // Semi-major axis in KM
534 //double sunTheta0 (0.533128 * CalendarAstronomer::PI/180) // Angular diameter at R0
535
536 // The following three methods, which compute the sun parameters
537 // given above for an arbitrary epoch (whatever time the object is
538 // set to), make only a small difference as compared to using the
539 // above constants. E.g., Sunset times might differ by ~12
540 // seconds. Furthermore, the eta-g computation is befuddled by
541 // Duffet-Smith's incorrect coefficients (p.86). I've corrected
542 // the first-order coefficient but the others may be off too - no
543 // way of knowing without consulting another source.
544
545 // /**
546 // * Return the sun's ecliptic longitude at perigee for the current time.
547 // * See Duffett-Smith, p. 86.
548 // * @return radians
549 // */
550 // private double getSunOmegaG() {
551 // double T = getJulianCentury();
552 // return (281.2208444 + (1.719175 + 0.000452778*T)*T) * DEG_RAD;
553 // }
554
555 // /**
556 // * Return the sun's ecliptic longitude for the current time.
557 // * See Duffett-Smith, p. 86.
558 // * @return radians
559 // */
560 // private double getSunEtaG() {
561 // double T = getJulianCentury();
562 // //return (279.6966778 + (36000.76892 + 0.0003025*T)*T) * DEG_RAD;
563 // //
564 // // The above line is from Duffett-Smith, and yields manifestly wrong
565 // // results. The below constant is derived empirically to match the
566 // // constant he gives for the 1990 EPOCH.
567 // //
568 // return (279.6966778 + (-0.3262541582718024 + 0.0003025*T)*T) * DEG_RAD;
569 // }
570
571 // /**
572 // * Return the sun's eccentricity of orbit for the current time.
573 // * See Duffett-Smith, p. 86.
574 // * @return double
575 // */
576 // private double getSunE() {
577 // double T = getJulianCentury();
578 // return 0.01675104 - (0.0000418 + 0.000000126*T)*T;
579 // }
580
581 /**
582 * Find the "true anomaly" (longitude) of an object from
583 * its mean anomaly and the eccentricity of its orbit. This uses
584 * an iterative solution to Kepler's equation.
585 *
586 * @param meanAnomaly The object's longitude calculated as if it were in
587 * a regular, circular orbit, measured in radians
588 * from the point of perigee.
589 *
590 * @param eccentricity The eccentricity of the orbit
591 *
592 * @return The true anomaly (longitude) measured in radians
593 */
594 static double trueAnomaly(double meanAnomaly, double eccentricity)
595 {
596 // First, solve Kepler's equation iteratively
597 // Duffett-Smith, p.90
598 double delta;
599 double E = meanAnomaly;
600 do {
601 delta = E - eccentricity * ::sin(E) - meanAnomaly;
602 E = E - delta / (1 - eccentricity * ::cos(E));
603 }
604 while (uprv_fabs(delta) > 1e-5); // epsilon = 1e-5 rad
605
606 return 2.0 * ::atan( ::tan(E/2) * ::sqrt( (1+eccentricity)
607 /(1-eccentricity) ) );
608 }
609
610 /**
611 * The longitude of the sun at the time specified by this object.
612 * The longitude is measured in radians along the ecliptic
613 * from the "first point of Aries," the point at which the ecliptic
614 * crosses the earth's equatorial plane at the vernal equinox.
615 * <p>
616 * Currently, this method uses an approximation of the two-body Kepler's
617 * equation for the earth and the sun. It does not take into account the
618 * perturbations caused by the other planets, the moon, etc.
619 * @internal
620 * @deprecated ICU 2.4. This class may be removed or modified.
621 */
622 double CalendarAstronomer::getSunLongitude()
623 {
624 // See page 86 of "Practial Astronomy with your Calculator",
625 // by Peter Duffet-Smith, for details on the algorithm.
626
627 if (isINVALID(sunLongitude)) {
628 getSunLongitude(getJulianDay(), sunLongitude, meanAnomalySun);
629 }
630 return sunLongitude;
631 }
632
633 /**
634 * TODO Make this public when the entire class is package-private.
635 */
636 /*public*/ void CalendarAstronomer::getSunLongitude(double jDay, double &longitude, double &meanAnomaly)
637 {
638 // See page 86 of "Practial Astronomy with your Calculator",
639 // by Peter Duffet-Smith, for details on the algorithm.
640
641 double day = jDay - JD_EPOCH; // Days since epoch
642
643 // Find the angular distance the sun in a fictitious
644 // circular orbit has travelled since the epoch.
645 double epochAngle = norm2PI(CalendarAstronomer_PI2/TROPICAL_YEAR*day);
646
647 // The epoch wasn't at the sun's perigee; find the angular distance
648 // since perigee, which is called the "mean anomaly"
649 meanAnomaly = norm2PI(epochAngle + SUN_ETA_G - SUN_OMEGA_G);
650
651 // Now find the "true anomaly", e.g. the real solar longitude
652 // by solving Kepler's equation for an elliptical orbit
653 // NOTE: The 3rd ed. of the book lists omega_g and eta_g in different
654 // equations; omega_g is to be correct.
655 longitude = norm2PI(trueAnomaly(meanAnomaly, SUN_E) + SUN_OMEGA_G);
656 }
657
658 /**
659 * The position of the sun at this object's current date and time,
660 * in equatorial coordinates.
661 * @internal
662 * @deprecated ICU 2.4. This class may be removed or modified.
663 */
664 CalendarAstronomer::Equatorial& CalendarAstronomer::getSunPosition(CalendarAstronomer::Equatorial& result) {
665 return eclipticToEquatorial(result, getSunLongitude(), 0);
666 }
667
668
669 /**
670 * Constant representing the vernal equinox.
671 * For use with {@link #getSunTime getSunTime}.
672 * Note: In this case, "vernal" refers to the northern hemisphere's seasons.
673 * @internal
674 * @deprecated ICU 2.4. This class may be removed or modified.
675 */
676 /*double CalendarAstronomer::VERNAL_EQUINOX() {
677 return 0;
678 }*/
679
680 /**
681 * Constant representing the summer solstice.
682 * For use with {@link #getSunTime getSunTime}.
683 * Note: In this case, "summer" refers to the northern hemisphere's seasons.
684 * @internal
685 * @deprecated ICU 2.4. This class may be removed or modified.
686 */
687 double CalendarAstronomer::SUMMER_SOLSTICE() {
688 return (CalendarAstronomer::PI/2);
689 }
690
691 /**
692 * Constant representing the autumnal equinox.
693 * For use with {@link #getSunTime getSunTime}.
694 * Note: In this case, "autumn" refers to the northern hemisphere's seasons.
695 * @internal
696 * @deprecated ICU 2.4. This class may be removed or modified.
697 */
698 /*double CalendarAstronomer::AUTUMN_EQUINOX() {
699 return (CalendarAstronomer::PI);
700 }*/
701
702 /**
703 * Constant representing the winter solstice.
704 * For use with {@link #getSunTime getSunTime}.
705 * Note: In this case, "winter" refers to the northern hemisphere's seasons.
706 * @internal
707 * @deprecated ICU 2.4. This class may be removed or modified.
708 */
709 double CalendarAstronomer::WINTER_SOLSTICE() {
710 return ((CalendarAstronomer::PI*3)/2);
711 }
712
713 CalendarAstronomer::AngleFunc::~AngleFunc() {}
714
715 /**
716 * Find the next time at which the sun's ecliptic longitude will have
717 * the desired value.
718 * @internal
719 * @deprecated ICU 2.4. This class may be removed or modified.
720 */
721 class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc {
722 public:
723 virtual ~SunTimeAngleFunc();
724 virtual double eval(CalendarAstronomer& a) { return a.getSunLongitude(); }
725 };
726
727 SunTimeAngleFunc::~SunTimeAngleFunc() {}
728
729 UDate CalendarAstronomer::getSunTime(double desired, UBool next)
730 {
731 SunTimeAngleFunc func;
732 return timeOfAngle( func,
733 desired,
734 TROPICAL_YEAR,
735 MINUTE_MS,
736 next);
737 }
738
739 CalendarAstronomer::CoordFunc::~CoordFunc() {}
740
741 class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
742 public:
743 virtual ~RiseSetCoordFunc();
744 virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { a.getSunPosition(result); }
745 };
746
747 RiseSetCoordFunc::~RiseSetCoordFunc() {}
748
749 UDate CalendarAstronomer::getSunRiseSet(UBool rise)
750 {
751 UDate t0 = fTime;
752
753 // Make a rough guess: 6am or 6pm local time on the current day
754 double noon = ClockMath::floorDivide(fTime + fGmtOffset, (double)DAY_MS)*DAY_MS - fGmtOffset + (12*HOUR_MS);
755
756 U_DEBUG_ASTRO_MSG(("Noon=%.2lf, %sL, gmtoff %.2lf\n", noon, debug_astro_date(noon+fGmtOffset), fGmtOffset));
757 setTime(noon + ((rise ? -6 : 6) * HOUR_MS));
758 U_DEBUG_ASTRO_MSG(("added %.2lf ms as a guess,\n", ((rise ? -6. : 6.) * HOUR_MS)));
759
760 RiseSetCoordFunc func;
761 double t = riseOrSet(func,
762 rise,
763 .533 * DEG_RAD, // Angular Diameter
764 34. /60.0 * DEG_RAD, // Refraction correction
765 MINUTE_MS / 12.); // Desired accuracy
766
767 setTime(t0);
768 return t;
769 }
770
771 // Commented out - currently unused. ICU 2.6, Alan
772 // //-------------------------------------------------------------------------
773 // // Alternate Sun Rise/Set
774 // // See Duffett-Smith p.93
775 // //-------------------------------------------------------------------------
776 //
777 // // This yields worse results (as compared to USNO data) than getSunRiseSet().
778 // /**
779 // * TODO Make this when the entire class is package-private.
780 // */
781 // /*public*/ long getSunRiseSet2(boolean rise) {
782 // // 1. Calculate coordinates of the sun's center for midnight
783 // double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
784 // double[] sl = getSunLongitude(jd);// double lambda1 = sl[0];
785 // Equatorial pos1 = eclipticToEquatorial(lambda1, 0);
786 //
787 // // 2. Add ... to lambda to get position 24 hours later
788 // double lambda2 = lambda1 + 0.985647*DEG_RAD;
789 // Equatorial pos2 = eclipticToEquatorial(lambda2, 0);
790 //
791 // // 3. Calculate LSTs of rising and setting for these two positions
792 // double tanL = ::tan(fLatitude);
793 // double H = ::acos(-tanL * ::tan(pos1.declination));
794 // double lst1r = (CalendarAstronomer_PI2 + pos1.ascension - H) * 24 / CalendarAstronomer_PI2;
795 // double lst1s = (pos1.ascension + H) * 24 / CalendarAstronomer_PI2;
796 // H = ::acos(-tanL * ::tan(pos2.declination));
797 // double lst2r = (CalendarAstronomer_PI2-H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
798 // double lst2s = (H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
799 // if (lst1r > 24) lst1r -= 24;
800 // if (lst1s > 24) lst1s -= 24;
801 // if (lst2r > 24) lst2r -= 24;
802 // if (lst2s > 24) lst2s -= 24;
803 //
804 // // 4. Convert LSTs to GSTs. If GST1 > GST2, add 24 to GST2.
805 // double gst1r = lstToGst(lst1r);
806 // double gst1s = lstToGst(lst1s);
807 // double gst2r = lstToGst(lst2r);
808 // double gst2s = lstToGst(lst2s);
809 // if (gst1r > gst2r) gst2r += 24;
810 // if (gst1s > gst2s) gst2s += 24;
811 //
812 // // 5. Calculate GST at 0h UT of this date
813 // double t00 = utToGst(0);
814 //
815 // // 6. Calculate GST at 0h on the observer's longitude
816 // double offset = ::round(fLongitude*12/PI); // p.95 step 6; he _rounds_ to nearest 15 deg.
817 // double t00p = t00 - offset*1.002737909;
818 // if (t00p < 0) t00p += 24; // do NOT normalize
819 //
820 // // 7. Adjust
821 // if (gst1r < t00p) {
822 // gst1r += 24;
823 // gst2r += 24;
824 // }
825 // if (gst1s < t00p) {
826 // gst1s += 24;
827 // gst2s += 24;
828 // }
829 //
830 // // 8.
831 // double gstr = (24.07*gst1r-t00*(gst2r-gst1r))/(24.07+gst1r-gst2r);
832 // double gsts = (24.07*gst1s-t00*(gst2s-gst1s))/(24.07+gst1s-gst2s);
833 //
834 // // 9. Correct for parallax, refraction, and sun's diameter
835 // double dec = (pos1.declination + pos2.declination) / 2;
836 // double psi = ::acos(sin(fLatitude) / cos(dec));
837 // double x = 0.830725 * DEG_RAD; // parallax+refraction+diameter
838 // double y = ::asin(sin(x) / ::sin(psi)) * RAD_DEG;
839 // double delta_t = 240 * y / cos(dec) / 3600; // hours
840 //
841 // // 10. Add correction to GSTs, subtract from GSTr
842 // gstr -= delta_t;
843 // gsts += delta_t;
844 //
845 // // 11. Convert GST to UT and then to local civil time
846 // double ut = gstToUt(rise ? gstr : gsts);
847 // //System.out.println((rise?"rise=":"set=") + ut + ", delta_t=" + delta_t);
848 // long midnight = DAY_MS * (time / DAY_MS); // Find UT midnight on this day
849 // return midnight + (long) (ut * 3600000);
850 // }
851
852 // Commented out - currently unused. ICU 2.6, Alan
853 // /**
854 // * Convert local sidereal time to Greenwich sidereal time.
855 // * Section 15. Duffett-Smith p.21
856 // * @param lst in hours (0..24)
857 // * @return GST in hours (0..24)
858 // */
859 // double lstToGst(double lst) {
860 // double delta = fLongitude * 24 / CalendarAstronomer_PI2;
861 // return normalize(lst - delta, 24);
862 // }
863
864 // Commented out - currently unused. ICU 2.6, Alan
865 // /**
866 // * Convert UT to GST on this date.
867 // * Section 12. Duffett-Smith p.17
868 // * @param ut in hours
869 // * @return GST in hours
870 // */
871 // double utToGst(double ut) {
872 // return normalize(getT0() + ut*1.002737909, 24);
873 // }
874
875 // Commented out - currently unused. ICU 2.6, Alan
876 // /**
877 // * Convert GST to UT on this date.
878 // * Section 13. Duffett-Smith p.18
879 // * @param gst in hours
880 // * @return UT in hours
881 // */
882 // double gstToUt(double gst) {
883 // return normalize(gst - getT0(), 24) * 0.9972695663;
884 // }
885
886 // Commented out - currently unused. ICU 2.6, Alan
887 // double getT0() {
888 // // Common computation for UT <=> GST
889 //
890 // // Find JD for 0h UT
891 // double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
892 //
893 // double s = jd - 2451545.0;
894 // double t = s / 36525.0;
895 // double t0 = 6.697374558 + (2400.051336 + 0.000025862*t)*t;
896 // return t0;
897 // }
898
899 // Commented out - currently unused. ICU 2.6, Alan
900 // //-------------------------------------------------------------------------
901 // // Alternate Sun Rise/Set
902 // // See sci.astro FAQ
903 // // http://www.faqs.org/faqs/astronomy/faq/part3/section-5.html
904 // //-------------------------------------------------------------------------
905 //
906 // // Note: This method appears to produce inferior accuracy as
907 // // compared to getSunRiseSet().
908 //
909 // /**
910 // * TODO Make this when the entire class is package-private.
911 // */
912 // /*public*/ long getSunRiseSet3(boolean rise) {
913 //
914 // // Compute day number for 0.0 Jan 2000 epoch
915 // double d = (double)(time - EPOCH_2000_MS) / DAY_MS;
916 //
917 // // Now compute the Local Sidereal Time, LST:
918 // //
919 // double LST = 98.9818 + 0.985647352 * d + /*UT*15 + long*/
920 // fLongitude*RAD_DEG;
921 // //
922 // // (east long. positive). Note that LST is here expressed in degrees,
923 // // where 15 degrees corresponds to one hour. Since LST really is an angle,
924 // // it's convenient to use one unit---degrees---throughout.
925 //
926 // // COMPUTING THE SUN'S POSITION
927 // // ----------------------------
928 // //
929 // // To be able to compute the Sun's rise/set times, you need to be able to
930 // // compute the Sun's position at any time. First compute the "day
931 // // number" d as outlined above, for the desired moment. Next compute:
932 // //
933 // double oblecl = 23.4393 - 3.563E-7 * d;
934 // //
935 // double w = 282.9404 + 4.70935E-5 * d;
936 // double M = 356.0470 + 0.9856002585 * d;
937 // double e = 0.016709 - 1.151E-9 * d;
938 // //
939 // // This is the obliquity of the ecliptic, plus some of the elements of
940 // // the Sun's apparent orbit (i.e., really the Earth's orbit): w =
941 // // argument of perihelion, M = mean anomaly, e = eccentricity.
942 // // Semi-major axis is here assumed to be exactly 1.0 (while not strictly
943 // // true, this is still an accurate approximation). Next compute E, the
944 // // eccentric anomaly:
945 // //
946 // double E = M + e*(180/PI) * ::sin(M*DEG_RAD) * ( 1.0 + e*cos(M*DEG_RAD) );
947 // //
948 // // where E and M are in degrees. This is it---no further iterations are
949 // // needed because we know e has a sufficiently small value. Next compute
950 // // the true anomaly, v, and the distance, r:
951 // //
952 // /* r * cos(v) = */ double A = cos(E*DEG_RAD) - e;
953 // /* r * ::sin(v) = */ double B = ::sqrt(1 - e*e) * ::sin(E*DEG_RAD);
954 // //
955 // // and
956 // //
957 // // r = sqrt( A*A + B*B )
958 // double v = ::atan2( B, A )*RAD_DEG;
959 // //
960 // // The Sun's true longitude, slon, can now be computed:
961 // //
962 // double slon = v + w;
963 // //
964 // // Since the Sun is always at the ecliptic (or at least very very close to
965 // // it), we can use simplified formulae to convert slon (the Sun's ecliptic
966 // // longitude) to sRA and sDec (the Sun's RA and Dec):
967 // //
968 // // ::sin(slon) * cos(oblecl)
969 // // tan(sRA) = -------------------------
970 // // cos(slon)
971 // //
972 // // ::sin(sDec) = ::sin(oblecl) * ::sin(slon)
973 // //
974 // // As was the case when computing az, the Azimuth, if possible use an
975 // // atan2() function to compute sRA.
976 //
977 // double sRA = ::atan2(sin(slon*DEG_RAD) * cos(oblecl*DEG_RAD), cos(slon*DEG_RAD))*RAD_DEG;
978 //
979 // double sin_sDec = ::sin(oblecl*DEG_RAD) * ::sin(slon*DEG_RAD);
980 // double sDec = ::asin(sin_sDec)*RAD_DEG;
981 //
982 // // COMPUTING RISE AND SET TIMES
983 // // ----------------------------
984 // //
985 // // To compute when an object rises or sets, you must compute when it
986 // // passes the meridian and the HA of rise/set. Then the rise time is
987 // // the meridian time minus HA for rise/set, and the set time is the
988 // // meridian time plus the HA for rise/set.
989 // //
990 // // To find the meridian time, compute the Local Sidereal Time at 0h local
991 // // time (or 0h UT if you prefer to work in UT) as outlined above---name
992 // // that quantity LST0. The Meridian Time, MT, will now be:
993 // //
994 // // MT = RA - LST0
995 // double MT = normalize(sRA - LST, 360);
996 // //
997 // // where "RA" is the object's Right Ascension (in degrees!). If negative,
998 // // add 360 deg to MT. If the object is the Sun, leave the time as it is,
999 // // but if it's stellar, multiply MT by 365.2422/366.2422, to convert from
1000 // // sidereal to solar time. Now, compute HA for rise/set, name that
1001 // // quantity HA0:
1002 // //
1003 // // ::sin(h0) - ::sin(lat) * ::sin(Dec)
1004 // // cos(HA0) = ---------------------------------
1005 // // cos(lat) * cos(Dec)
1006 // //
1007 // // where h0 is the altitude selected to represent rise/set. For a purely
1008 // // mathematical horizon, set h0 = 0 and simplify to:
1009 // //
1010 // // cos(HA0) = - tan(lat) * tan(Dec)
1011 // //
1012 // // If you want to account for refraction on the atmosphere, set h0 = -35/60
1013 // // degrees (-35 arc minutes), and if you want to compute the rise/set times
1014 // // for the Sun's upper limb, set h0 = -50/60 (-50 arc minutes).
1015 // //
1016 // double h0 = -50/60 * DEG_RAD;
1017 //
1018 // double HA0 = ::acos(
1019 // (sin(h0) - ::sin(fLatitude) * sin_sDec) /
1020 // (cos(fLatitude) * cos(sDec*DEG_RAD)))*RAD_DEG;
1021 //
1022 // // When HA0 has been computed, leave it as it is for the Sun but multiply
1023 // // by 365.2422/366.2422 for stellar objects, to convert from sidereal to
1024 // // solar time. Finally compute:
1025 // //
1026 // // Rise time = MT - HA0
1027 // // Set time = MT + HA0
1028 // //
1029 // // convert the times from degrees to hours by dividing by 15.
1030 // //
1031 // // If you'd like to check that your calculations are accurate or just
1032 // // need a quick result, check the USNO's Sun or Moon Rise/Set Table,
1033 // // <URL:http://aa.usno.navy.mil/AA/data/docs/RS_OneYear.html>.
1034 //
1035 // double result = MT + (rise ? -HA0 : HA0); // in degrees
1036 //
1037 // // Find UT midnight on this day
1038 // long midnight = DAY_MS * (time / DAY_MS);
1039 //
1040 // return midnight + (long) (result * 3600000 / 15);
1041 // }
1042
1043 //-------------------------------------------------------------------------
1044 // The Moon
1045 //-------------------------------------------------------------------------
1046
1047 #define moonL0 (318.351648 * CalendarAstronomer::PI/180 ) // Mean long. at epoch
1048 #define moonP0 ( 36.340410 * CalendarAstronomer::PI/180 ) // Mean long. of perigee
1049 #define moonN0 ( 318.510107 * CalendarAstronomer::PI/180 ) // Mean long. of node
1050 #define moonI ( 5.145366 * CalendarAstronomer::PI/180 ) // Inclination of orbit
1051 #define moonE ( 0.054900 ) // Eccentricity of orbit
1052
1053 // These aren't used right now
1054 #define moonA ( 3.84401e5 ) // semi-major axis (km)
1055 #define moonT0 ( 0.5181 * CalendarAstronomer::PI/180 ) // Angular size at distance A
1056 #define moonPi ( 0.9507 * CalendarAstronomer::PI/180 ) // Parallax at distance A
1057
1058 /**
1059 * The position of the moon at the time set on this
1060 * object, in equatorial coordinates.
1061 * @internal
1062 * @deprecated ICU 2.4. This class may be removed or modified.
1063 */
1064 const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition()
1065 {
1066 //
1067 // See page 142 of "Practial Astronomy with your Calculator",
1068 // by Peter Duffet-Smith, for details on the algorithm.
1069 //
1070 if (moonPositionSet == FALSE) {
1071 // Calculate the solar longitude. Has the side effect of
1072 // filling in "meanAnomalySun" as well.
1073 getSunLongitude();
1074
1075 //
1076 // Find the # of days since the epoch of our orbital parameters.
1077 // TODO: Convert the time of day portion into ephemeris time
1078 //
1079 double day = getJulianDay() - JD_EPOCH; // Days since epoch
1080
1081 // Calculate the mean longitude and anomaly of the moon, based on
1082 // a circular orbit. Similar to the corresponding solar calculation.
1083 double meanLongitude = norm2PI(13.1763966*PI/180*day + moonL0);
1084 meanAnomalyMoon = norm2PI(meanLongitude - 0.1114041*PI/180 * day - moonP0);
1085
1086 //
1087 // Calculate the following corrections:
1088 // Evection: the sun's gravity affects the moon's eccentricity
1089 // Annual Eqn: variation in the effect due to earth-sun distance
1090 // A3: correction factor (for ???)
1091 //
1092 double evection = 1.2739*PI/180 * ::sin(2 * (meanLongitude - sunLongitude)
1093 - meanAnomalyMoon);
1094 double annual = 0.1858*PI/180 * ::sin(meanAnomalySun);
1095 double a3 = 0.3700*PI/180 * ::sin(meanAnomalySun);
1096
1097 meanAnomalyMoon += evection - annual - a3;
1098
1099 //
1100 // More correction factors:
1101 // center equation of the center correction
1102 // a4 yet another error correction (???)
1103 //
1104 // TODO: Skip the equation of the center correction and solve Kepler's eqn?
1105 //
1106 double center = 6.2886*PI/180 * ::sin(meanAnomalyMoon);
1107 double a4 = 0.2140*PI/180 * ::sin(2 * meanAnomalyMoon);
1108
1109 // Now find the moon's corrected longitude
1110 moonLongitude = meanLongitude + evection + center - annual + a4;
1111
1112 //
1113 // And finally, find the variation, caused by the fact that the sun's
1114 // gravitational pull on the moon varies depending on which side of
1115 // the earth the moon is on
1116 //
1117 double variation = 0.6583*CalendarAstronomer::PI/180 * ::sin(2*(moonLongitude - sunLongitude));
1118
1119 moonLongitude += variation;
1120
1121 //
1122 // What we've calculated so far is the moon's longitude in the plane
1123 // of its own orbit. Now map to the ecliptic to get the latitude
1124 // and longitude. First we need to find the longitude of the ascending
1125 // node, the position on the ecliptic where it is crossed by the moon's
1126 // orbit as it crosses from the southern to the northern hemisphere.
1127 //
1128 double nodeLongitude = norm2PI(moonN0 - 0.0529539*PI/180 * day);
1129
1130 nodeLongitude -= 0.16*PI/180 * ::sin(meanAnomalySun);
1131
1132 double y = ::sin(moonLongitude - nodeLongitude);
1133 double x = cos(moonLongitude - nodeLongitude);
1134
1135 moonEclipLong = ::atan2(y*cos(moonI), x) + nodeLongitude;
1136 double moonEclipLat = ::asin(y * ::sin(moonI));
1137
1138 eclipticToEquatorial(moonPosition, moonEclipLong, moonEclipLat);
1139 moonPositionSet = TRUE;
1140 }
1141 return moonPosition;
1142 }
1143
1144 /**
1145 * The "age" of the moon at the time specified in this object.
1146 * This is really the angle between the
1147 * current ecliptic longitudes of the sun and the moon,
1148 * measured in radians.
1149 *
1150 * @see #getMoonPhase
1151 * @internal
1152 * @deprecated ICU 2.4. This class may be removed or modified.
1153 */
1154 double CalendarAstronomer::getMoonAge() {
1155 // See page 147 of "Practial Astronomy with your Calculator",
1156 // by Peter Duffet-Smith, for details on the algorithm.
1157 //
1158 // Force the moon's position to be calculated. We're going to use
1159 // some the intermediate results cached during that calculation.
1160 //
1161 getMoonPosition();
1162
1163 return norm2PI(moonEclipLong - sunLongitude);
1164 }
1165
1166 /**
1167 * Calculate the phase of the moon at the time set in this object.
1168 * The returned phase is a <code>double</code> in the range
1169 * <code>0 <= phase < 1</code>, interpreted as follows:
1170 * <ul>
1171 * <li>0.00: New moon
1172 * <li>0.25: First quarter
1173 * <li>0.50: Full moon
1174 * <li>0.75: Last quarter
1175 * </ul>
1176 *
1177 * @see #getMoonAge
1178 * @internal
1179 * @deprecated ICU 2.4. This class may be removed or modified.
1180 */
1181 double CalendarAstronomer::getMoonPhase() {
1182 // See page 147 of "Practial Astronomy with your Calculator",
1183 // by Peter Duffet-Smith, for details on the algorithm.
1184 return 0.5 * (1 - cos(getMoonAge()));
1185 }
1186
1187 /**
1188 * Constant representing a new moon.
1189 * For use with {@link #getMoonTime getMoonTime}
1190 * @internal
1191 * @deprecated ICU 2.4. This class may be removed or modified.
1192 */
1193 const CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() {
1194 return CalendarAstronomer::MoonAge(0);
1195 }
1196
1197 /**
1198 * Constant representing the moon's first quarter.
1199 * For use with {@link #getMoonTime getMoonTime}
1200 * @internal
1201 * @deprecated ICU 2.4. This class may be removed or modified.
1202 */
1203 /*const CalendarAstronomer::MoonAge CalendarAstronomer::FIRST_QUARTER() {
1204 return CalendarAstronomer::MoonAge(CalendarAstronomer::PI/2);
1205 }*/
1206
1207 /**
1208 * Constant representing a full moon.
1209 * For use with {@link #getMoonTime getMoonTime}
1210 * @internal
1211 * @deprecated ICU 2.4. This class may be removed or modified.
1212 */
1213 const CalendarAstronomer::MoonAge CalendarAstronomer::FULL_MOON() {
1214 return CalendarAstronomer::MoonAge(CalendarAstronomer::PI);
1215 }
1216 /**
1217 * Constant representing the moon's last quarter.
1218 * For use with {@link #getMoonTime getMoonTime}
1219 * @internal
1220 * @deprecated ICU 2.4. This class may be removed or modified.
1221 */
1222
1223 class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc {
1224 public:
1225 virtual ~MoonTimeAngleFunc();
1226 virtual double eval(CalendarAstronomer&a) { return a.getMoonAge(); }
1227 };
1228
1229 MoonTimeAngleFunc::~MoonTimeAngleFunc() {}
1230
1231 /*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() {
1232 return CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2);
1233 }*/
1234
1235 /**
1236 * Find the next or previous time at which the Moon's ecliptic
1237 * longitude will have the desired value.
1238 * <p>
1239 * @param desired The desired longitude.
1240 * @param next <tt>true</tt> if the next occurrance of the phase
1241 * is desired, <tt>false</tt> for the previous occurrance.
1242 * @internal
1243 * @deprecated ICU 2.4. This class may be removed or modified.
1244 */
1245 UDate CalendarAstronomer::getMoonTime(double desired, UBool next)
1246 {
1247 MoonTimeAngleFunc func;
1248 return timeOfAngle( func,
1249 desired,
1250 SYNODIC_MONTH,
1251 MINUTE_MS,
1252 next);
1253 }
1254
1255 /**
1256 * Find the next or previous time at which the moon will be in the
1257 * desired phase.
1258 * <p>
1259 * @param desired The desired phase of the moon.
1260 * @param next <tt>true</tt> if the next occurrance of the phase
1261 * is desired, <tt>false</tt> for the previous occurrance.
1262 * @internal
1263 * @deprecated ICU 2.4. This class may be removed or modified.
1264 */
1265 UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) {
1266 return getMoonTime(desired.value, next);
1267 }
1268
1269 class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
1270 public:
1271 virtual ~MoonRiseSetCoordFunc();
1272 virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { result = a.getMoonPosition(); }
1273 };
1274
1275 MoonRiseSetCoordFunc::~MoonRiseSetCoordFunc() {}
1276
1277 /**
1278 * Returns the time (GMT) of sunrise or sunset on the local date to which
1279 * this calendar is currently set.
1280 * @internal
1281 * @deprecated ICU 2.4. This class may be removed or modified.
1282 */
1283 UDate CalendarAstronomer::getMoonRiseSet(UBool rise)
1284 {
1285 MoonRiseSetCoordFunc func;
1286 return riseOrSet(func,
1287 rise,
1288 .533 * DEG_RAD, // Angular Diameter
1289 34 /60.0 * DEG_RAD, // Refraction correction
1290 MINUTE_MS); // Desired accuracy
1291 }
1292
1293 //-------------------------------------------------------------------------
1294 // Interpolation methods for finding the time at which a given event occurs
1295 //-------------------------------------------------------------------------
1296
1297 UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired,
1298 double periodDays, double epsilon, UBool next)
1299 {
1300 // Find the value of the function at the current time
1301 double lastAngle = func.eval(*this);
1302
1303 // Find out how far we are from the desired angle
1304 double deltaAngle = norm2PI(desired - lastAngle) ;
1305
1306 // Using the average period, estimate the next (or previous) time at
1307 // which the desired angle occurs.
1308 double deltaT = (deltaAngle + (next ? 0.0 : - CalendarAstronomer_PI2 )) * (periodDays*DAY_MS) / CalendarAstronomer_PI2;
1309
1310 double lastDeltaT = deltaT; // Liu
1311 UDate startTime = fTime; // Liu
1312
1313 setTime(fTime + uprv_ceil(deltaT));
1314
1315 // Now iterate until we get the error below epsilon. Throughout
1316 // this loop we use normPI to get values in the range -Pi to Pi,
1317 // since we're using them as correction factors rather than absolute angles.
1318 do {
1319 // Evaluate the function at the time we've estimated
1320 double angle = func.eval(*this);
1321
1322 // Find the # of milliseconds per radian at this point on the curve
1323 double factor = uprv_fabs(deltaT / normPI(angle-lastAngle));
1324
1325 // Correct the time estimate based on how far off the angle is
1326 deltaT = normPI(desired - angle) * factor;
1327
1328 // HACK:
1329 //
1330 // If abs(deltaT) begins to diverge we need to quit this loop.
1331 // This only appears to happen when attempting to locate, for
1332 // example, a new moon on the day of the new moon. E.g.:
1333 //
1334 // This result is correct:
1335 // newMoon(7508(Mon Jul 23 00:00:00 CST 1990,false))=
1336 // Sun Jul 22 10:57:41 CST 1990
1337 //
1338 // But attempting to make the same call a day earlier causes deltaT
1339 // to diverge:
1340 // CalendarAstronomer.timeOfAngle() diverging: 1.348508727575625E9 ->
1341 // 1.3649828540224032E9
1342 // newMoon(7507(Sun Jul 22 00:00:00 CST 1990,false))=
1343 // Sun Jul 08 13:56:15 CST 1990
1344 //
1345 // As a temporary solution, we catch this specific condition and
1346 // adjust our start time by one eighth period days (either forward
1347 // or backward) and try again.
1348 // Liu 11/9/00
1349 if (uprv_fabs(deltaT) > uprv_fabs(lastDeltaT)) {
1350 double delta = uprv_ceil (periodDays * DAY_MS / 8.0);
1351 setTime(startTime + (next ? delta : -delta));
1352 return timeOfAngle(func, desired, periodDays, epsilon, next);
1353 }
1354
1355 lastDeltaT = deltaT;
1356 lastAngle = angle;
1357
1358 setTime(fTime + uprv_ceil(deltaT));
1359 }
1360 while (uprv_fabs(deltaT) > epsilon);
1361
1362 return fTime;
1363 }
1364
1365 UDate CalendarAstronomer::riseOrSet(CoordFunc& func, UBool rise,
1366 double diameter, double refraction,
1367 double epsilon)
1368 {
1369 Equatorial pos;
1370 double tanL = ::tan(fLatitude);
1371 double deltaT = 0;
1372 int32_t count = 0;
1373
1374 //
1375 // Calculate the object's position at the current time, then use that
1376 // position to calculate the time of rising or setting. The position
1377 // will be different at that time, so iterate until the error is allowable.
1378 //
1379 U_DEBUG_ASTRO_MSG(("setup rise=%s, dia=%.3lf, ref=%.3lf, eps=%.3lf\n",
1380 rise?"T":"F", diameter, refraction, epsilon));
1381 do {
1382 // See "Practical Astronomy With Your Calculator, section 33.
1383 func.eval(pos, *this);
1384 double angle = ::acos(-tanL * ::tan(pos.declination));
1385 double lst = ((rise ? CalendarAstronomer_PI2-angle : angle) + pos.ascension ) * 24 / CalendarAstronomer_PI2;
1386
1387 // Convert from LST to Universal Time.
1388 UDate newTime = lstToUT( lst );
1389
1390 deltaT = newTime - fTime;
1391 setTime(newTime);
1392 U_DEBUG_ASTRO_MSG(("%d] dT=%.3lf, angle=%.3lf, lst=%.3lf, A=%.3lf/D=%.3lf\n",
1393 count, deltaT, angle, lst, pos.ascension, pos.declination));
1394 }
1395 while (++ count < 5 && uprv_fabs(deltaT) > epsilon);
1396
1397 // Calculate the correction due to refraction and the object's angular diameter
1398 double cosD = ::cos(pos.declination);
1399 double psi = ::acos(sin(fLatitude) / cosD);
1400 double x = diameter / 2 + refraction;
1401 double y = ::asin(sin(x) / ::sin(psi));
1402 long delta = (long)((240 * y * RAD_DEG / cosD)*SECOND_MS);
1403
1404 return fTime + (rise ? -delta : delta);
1405 }
1406 /**
1407 * Return the obliquity of the ecliptic (the angle between the ecliptic
1408 * and the earth's equator) at the current time. This varies due to
1409 * the precession of the earth's axis.
1410 *
1411 * @return the obliquity of the ecliptic relative to the equator,
1412 * measured in radians.
1413 */
1414 double CalendarAstronomer::eclipticObliquity() {
1415 if (isINVALID(eclipObliquity)) {
1416 const double epoch = 2451545.0; // 2000 AD, January 1.5
1417
1418 double T = (getJulianDay() - epoch) / 36525;
1419
1420 eclipObliquity = 23.439292
1421 - 46.815/3600 * T
1422 - 0.0006/3600 * T*T
1423 + 0.00181/3600 * T*T*T;
1424
1425 eclipObliquity *= DEG_RAD;
1426 }
1427 return eclipObliquity;
1428 }
1429
1430
1431 //-------------------------------------------------------------------------
1432 // Private data
1433 //-------------------------------------------------------------------------
1434 void CalendarAstronomer::clearCache() {
1435 const double INVALID = uprv_getNaN();
1436
1437 julianDay = INVALID;
1438 julianCentury = INVALID;
1439 sunLongitude = INVALID;
1440 meanAnomalySun = INVALID;
1441 moonLongitude = INVALID;
1442 moonEclipLong = INVALID;
1443 meanAnomalyMoon = INVALID;
1444 eclipObliquity = INVALID;
1445 siderealTime = INVALID;
1446 siderealT0 = INVALID;
1447 moonPositionSet = FALSE;
1448 }
1449
1450 //private static void out(String s) {
1451 // System.out.println(s);
1452 //}
1453
1454 //private static String deg(double rad) {
1455 // return Double.toString(rad * RAD_DEG);
1456 //}
1457
1458 //private static String hours(long ms) {
1459 // return Double.toString((double)ms / HOUR_MS) + " hours";
1460 //}
1461
1462 /**
1463 * @internal
1464 * @deprecated ICU 2.4. This class may be removed or modified.
1465 */
1466 /*UDate CalendarAstronomer::local(UDate localMillis) {
1467 // TODO - srl ?
1468 TimeZone *tz = TimeZone::createDefault();
1469 int32_t rawOffset;
1470 int32_t dstOffset;
1471 UErrorCode status = U_ZERO_ERROR;
1472 tz->getOffset(localMillis, TRUE, rawOffset, dstOffset, status);
1473 delete tz;
1474 return localMillis - rawOffset;
1475 }*/
1476
1477 // Debugging functions
1478 UnicodeString CalendarAstronomer::Ecliptic::toString() const
1479 {
1480 #ifdef U_DEBUG_ASTRO
1481 char tmp[800];
1482 sprintf(tmp, "[%.5f,%.5f]", longitude*RAD_DEG, latitude*RAD_DEG);
1483 return UnicodeString(tmp, "");
1484 #else
1485 return UnicodeString();
1486 #endif
1487 }
1488
1489 UnicodeString CalendarAstronomer::Equatorial::toString() const
1490 {
1491 #ifdef U_DEBUG_ASTRO
1492 char tmp[400];
1493 sprintf(tmp, "%f,%f",
1494 (ascension*RAD_DEG), (declination*RAD_DEG));
1495 return UnicodeString(tmp, "");
1496 #else
1497 return UnicodeString();
1498 #endif
1499 }
1500
1501 UnicodeString CalendarAstronomer::Horizon::toString() const
1502 {
1503 #ifdef U_DEBUG_ASTRO
1504 char tmp[800];
1505 sprintf(tmp, "[%.5f,%.5f]", altitude*RAD_DEG, azimuth*RAD_DEG);
1506 return UnicodeString(tmp, "");
1507 #else
1508 return UnicodeString();
1509 #endif
1510 }
1511
1512
1513 // static private String radToHms(double angle) {
1514 // int hrs = (int) (angle*RAD_HOUR);
1515 // int min = (int)((angle*RAD_HOUR - hrs) * 60);
1516 // int sec = (int)((angle*RAD_HOUR - hrs - min/60.0) * 3600);
1517
1518 // return Integer.toString(hrs) + "h" + min + "m" + sec + "s";
1519 // }
1520
1521 // static private String radToDms(double angle) {
1522 // int deg = (int) (angle*RAD_DEG);
1523 // int min = (int)((angle*RAD_DEG - deg) * 60);
1524 // int sec = (int)((angle*RAD_DEG - deg - min/60.0) * 3600);
1525
1526 // return Integer.toString(deg) + "\u00b0" + min + "'" + sec + "\"";
1527 // }
1528
1529 // =============== Calendar Cache ================
1530
1531 void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) {
1532 ucln_i18n_registerCleanup(UCLN_I18N_ASTRO_CALENDAR, calendar_astro_cleanup);
1533 if(cache == NULL) {
1534 status = U_MEMORY_ALLOCATION_ERROR;
1535 } else {
1536 *cache = new CalendarCache(32, status);
1537 if(U_FAILURE(status)) {
1538 delete *cache;
1539 *cache = NULL;
1540 }
1541 }
1542 }
1543
1544 int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) {
1545 int32_t res;
1546
1547 if(U_FAILURE(status)) {
1548 return 0;
1549 }
1550 umtx_lock(&ccLock);
1551
1552 if(*cache == NULL) {
1553 createCache(cache, status);
1554 if(U_FAILURE(status)) {
1555 umtx_unlock(&ccLock);
1556 return 0;
1557 }
1558 }
1559
1560 res = uhash_igeti((*cache)->fTable, key);
1561 U_DEBUG_ASTRO_MSG(("%p: GET: [%d] == %d\n", (*cache)->fTable, key, res));
1562
1563 umtx_unlock(&ccLock);
1564 return res;
1565 }
1566
1567 void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) {
1568 if(U_FAILURE(status)) {
1569 return;
1570 }
1571 umtx_lock(&ccLock);
1572
1573 if(*cache == NULL) {
1574 createCache(cache, status);
1575 if(U_FAILURE(status)) {
1576 umtx_unlock(&ccLock);
1577 return;
1578 }
1579 }
1580
1581 uhash_iputi((*cache)->fTable, key, value, &status);
1582 U_DEBUG_ASTRO_MSG(("%p: PUT: [%d] := %d\n", (*cache)->fTable, key, value));
1583
1584 umtx_unlock(&ccLock);
1585 }
1586
1587 CalendarCache::CalendarCache(int32_t size, UErrorCode &status) {
1588 fTable = uhash_openSize(uhash_hashLong, uhash_compareLong, NULL, size, &status);
1589 U_DEBUG_ASTRO_MSG(("%p: Opening.\n", fTable));
1590 }
1591
1592 CalendarCache::~CalendarCache() {
1593 if(fTable != NULL) {
1594 U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable));
1595 uhash_close(fTable);
1596 }
1597 }
1598
1599 U_NAMESPACE_END
1600
1601 #endif // !UCONFIG_NO_FORMATTING

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