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1 : // © 2016 and later: Unicode, Inc. and others.
2 : // License & terms of use: http://www.unicode.org/copyright.html
3 : /************************************************************************
4 : * Copyright (C) 1996-2012, International Business Machines Corporation
5 : * and others. All Rights Reserved.
6 : ************************************************************************
7 : * 2003-nov-07 srl Port from Java
8 : */
9 :
10 : #include "astro.h"
11 :
12 : #if !UCONFIG_NO_FORMATTING
13 :
14 : #include "unicode/calendar.h"
15 : #include <math.h>
16 : #include <float.h>
17 : #include "unicode/putil.h"
18 : #include "uhash.h"
19 : #include "umutex.h"
20 : #include "ucln_in.h"
21 : #include "putilimp.h"
22 : #include <stdio.h> // for toString()
23 :
24 : #if defined (PI)
25 : #undef PI
26 : #endif
27 :
28 : #ifdef U_DEBUG_ASTRO
29 : # include "uresimp.h" // for debugging
30 :
31 : static void debug_astro_loc(const char *f, int32_t l)
32 : {
33 : fprintf(stderr, "%s:%d: ", f, l);
34 : }
35 :
36 : static void debug_astro_msg(const char *pat, ...)
37 : {
38 : va_list ap;
39 : va_start(ap, pat);
40 : vfprintf(stderr, pat, ap);
41 : fflush(stderr);
42 : }
43 : #include "unicode/datefmt.h"
44 : #include "unicode/ustring.h"
45 : static const char * debug_astro_date(UDate d) {
46 : static char gStrBuf[1024];
47 : static DateFormat *df = NULL;
48 : if(df == NULL) {
49 : df = DateFormat::createDateTimeInstance(DateFormat::MEDIUM, DateFormat::MEDIUM, Locale::getUS());
50 : df->adoptTimeZone(TimeZone::getGMT()->clone());
51 : }
52 : UnicodeString str;
53 : df->format(d,str);
54 : u_austrncpy(gStrBuf,str.getTerminatedBuffer(),sizeof(gStrBuf)-1);
55 : return gStrBuf;
56 : }
57 :
58 : // must use double parens, i.e.: U_DEBUG_ASTRO_MSG(("four is: %d",4));
59 : #define U_DEBUG_ASTRO_MSG(x) {debug_astro_loc(__FILE__,__LINE__);debug_astro_msg x;}
60 : #else
61 : #define U_DEBUG_ASTRO_MSG(x)
62 : #endif
63 :
64 0 : static inline UBool isINVALID(double d) {
65 0 : return(uprv_isNaN(d));
66 : }
67 :
68 : static UMutex ccLock = U_MUTEX_INITIALIZER;
69 :
70 : U_CDECL_BEGIN
71 0 : static UBool calendar_astro_cleanup(void) {
72 0 : return TRUE;
73 : }
74 : U_CDECL_END
75 :
76 : U_NAMESPACE_BEGIN
77 :
78 : /**
79 : * The number of standard hours in one sidereal day.
80 : * Approximately 24.93.
81 : * @internal
82 : * @deprecated ICU 2.4. This class may be removed or modified.
83 : */
84 : #define SIDEREAL_DAY (23.93446960027)
85 :
86 : /**
87 : * The number of sidereal hours in one mean solar day.
88 : * Approximately 24.07.
89 : * @internal
90 : * @deprecated ICU 2.4. This class may be removed or modified.
91 : */
92 : #define SOLAR_DAY (24.065709816)
93 :
94 : /**
95 : * The average number of solar days from one new moon to the next. This is the time
96 : * it takes for the moon to return the same ecliptic longitude as the sun.
97 : * It is longer than the sidereal month because the sun's longitude increases
98 : * during the year due to the revolution of the earth around the sun.
99 : * Approximately 29.53.
100 : *
101 : * @see #SIDEREAL_MONTH
102 : * @internal
103 : * @deprecated ICU 2.4. This class may be removed or modified.
104 : */
105 : const double CalendarAstronomer::SYNODIC_MONTH = 29.530588853;
106 :
107 : /**
108 : * The average number of days it takes
109 : * for the moon to return to the same ecliptic longitude relative to the
110 : * stellar background. This is referred to as the sidereal month.
111 : * It is shorter than the synodic month due to
112 : * the revolution of the earth around the sun.
113 : * Approximately 27.32.
114 : *
115 : * @see #SYNODIC_MONTH
116 : * @internal
117 : * @deprecated ICU 2.4. This class may be removed or modified.
118 : */
119 : #define SIDEREAL_MONTH 27.32166
120 :
121 : /**
122 : * The average number number of days between successive vernal equinoxes.
123 : * Due to the precession of the earth's
124 : * axis, this is not precisely the same as the sidereal year.
125 : * Approximately 365.24
126 : *
127 : * @see #SIDEREAL_YEAR
128 : * @internal
129 : * @deprecated ICU 2.4. This class may be removed or modified.
130 : */
131 : #define TROPICAL_YEAR 365.242191
132 :
133 : /**
134 : * The average number of days it takes
135 : * for the sun to return to the same position against the fixed stellar
136 : * background. This is the duration of one orbit of the earth about the sun
137 : * as it would appear to an outside observer.
138 : * Due to the precession of the earth's
139 : * axis, this is not precisely the same as the tropical year.
140 : * Approximately 365.25.
141 : *
142 : * @see #TROPICAL_YEAR
143 : * @internal
144 : * @deprecated ICU 2.4. This class may be removed or modified.
145 : */
146 : #define SIDEREAL_YEAR 365.25636
147 :
148 : //-------------------------------------------------------------------------
149 : // Time-related constants
150 : //-------------------------------------------------------------------------
151 :
152 : /**
153 : * The number of milliseconds in one second.
154 : * @internal
155 : * @deprecated ICU 2.4. This class may be removed or modified.
156 : */
157 : #define SECOND_MS U_MILLIS_PER_SECOND
158 :
159 : /**
160 : * The number of milliseconds in one minute.
161 : * @internal
162 : * @deprecated ICU 2.4. This class may be removed or modified.
163 : */
164 : #define MINUTE_MS U_MILLIS_PER_MINUTE
165 :
166 : /**
167 : * The number of milliseconds in one hour.
168 : * @internal
169 : * @deprecated ICU 2.4. This class may be removed or modified.
170 : */
171 : #define HOUR_MS U_MILLIS_PER_HOUR
172 :
173 : /**
174 : * The number of milliseconds in one day.
175 : * @internal
176 : * @deprecated ICU 2.4. This class may be removed or modified.
177 : */
178 : #define DAY_MS U_MILLIS_PER_DAY
179 :
180 : /**
181 : * The start of the julian day numbering scheme used by astronomers, which
182 : * is 1/1/4713 BC (Julian), 12:00 GMT. This is given as the number of milliseconds
183 : * since 1/1/1970 AD (Gregorian), a negative number.
184 : * Note that julian day numbers and
185 : * the Julian calendar are <em>not</em> the same thing. Also note that
186 : * julian days start at <em>noon</em>, not midnight.
187 : * @internal
188 : * @deprecated ICU 2.4. This class may be removed or modified.
189 : */
190 : #define JULIAN_EPOCH_MS -210866760000000.0
191 :
192 :
193 : /**
194 : * Milliseconds value for 0.0 January 2000 AD.
195 : */
196 : #define EPOCH_2000_MS 946598400000.0
197 :
198 : //-------------------------------------------------------------------------
199 : // Assorted private data used for conversions
200 : //-------------------------------------------------------------------------
201 :
202 : // My own copies of these so compilers are more likely to optimize them away
203 : const double CalendarAstronomer::PI = 3.14159265358979323846;
204 :
205 : #define CalendarAstronomer_PI2 (CalendarAstronomer::PI*2.0)
206 : #define RAD_HOUR ( 12 / CalendarAstronomer::PI ) // radians -> hours
207 : #define DEG_RAD ( CalendarAstronomer::PI / 180 ) // degrees -> radians
208 : #define RAD_DEG ( 180 / CalendarAstronomer::PI ) // radians -> degrees
209 :
210 : /***
211 : * Given 'value', add or subtract 'range' until 0 <= 'value' < range.
212 : * The modulus operator.
213 : */
214 0 : inline static double normalize(double value, double range) {
215 0 : 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 : */
223 0 : inline static double norm2PI(double angle) {
224 0 : return normalize(angle, CalendarAstronomer::PI * 2.0);
225 : }
226 :
227 : /**
228 : * Normalize an angle into the range -PI - PI
229 : */
230 0 : inline static double normPI(double angle) {
231 0 : 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 : */
244 0 : CalendarAstronomer::CalendarAstronomer():
245 0 : fTime(Calendar::getNow()), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
246 0 : clearCache();
247 0 : }
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 : */
255 0 : CalendarAstronomer::CalendarAstronomer(UDate d): fTime(d), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
256 0 : clearCache();
257 0 : }
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 : */
274 0 : CalendarAstronomer::CalendarAstronomer(double longitude, double latitude) :
275 0 : fTime(Calendar::getNow()), moonPosition(0,0), moonPositionSet(FALSE) {
276 0 : fLongitude = normPI(longitude * (double)DEG_RAD);
277 0 : fLatitude = normPI(latitude * (double)DEG_RAD);
278 0 : fGmtOffset = (double)(fLongitude * 24. * (double)HOUR_MS / (double)CalendarAstronomer_PI2);
279 0 : clearCache();
280 0 : }
281 :
282 0 : CalendarAstronomer::~CalendarAstronomer()
283 : {
284 0 : }
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 : */
302 0 : void CalendarAstronomer::setTime(UDate aTime) {
303 0 : fTime = aTime;
304 : U_DEBUG_ASTRO_MSG(("setTime(%.1lf, %sL)\n", aTime, debug_astro_date(aTime+fGmtOffset)));
305 0 : clearCache();
306 0 : }
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 : */
323 0 : void CalendarAstronomer::setJulianDay(double jdn) {
324 0 : fTime = (double)(jdn * DAY_MS) + JULIAN_EPOCH_MS;
325 0 : clearCache();
326 0 : julianDay = jdn;
327 0 : }
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 : */
339 0 : UDate CalendarAstronomer::getTime() {
340 0 : 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 : */
353 0 : double CalendarAstronomer::getJulianDay() {
354 0 : if (isINVALID(julianDay)) {
355 0 : julianDay = (fTime - (double)JULIAN_EPOCH_MS) / (double)DAY_MS;
356 : }
357 0 : 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 : */
368 0 : double CalendarAstronomer::getJulianCentury() {
369 0 : if (isINVALID(julianCentury)) {
370 0 : julianCentury = (getJulianDay() - 2415020.0) / 36525.0;
371 : }
372 0 : 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 : */
380 0 : double CalendarAstronomer::getGreenwichSidereal() {
381 0 : 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 0 : double UT = normalize(fTime/(double)HOUR_MS, 24.);
386 :
387 0 : siderealTime = normalize(getSiderealOffset() + UT*1.002737909, 24.);
388 : }
389 0 : return siderealTime;
390 : }
391 :
392 0 : double CalendarAstronomer::getSiderealOffset() {
393 0 : if (isINVALID(siderealT0)) {
394 0 : double JD = uprv_floor(getJulianDay() - 0.5) + 0.5;
395 0 : double S = JD - 2451545.0;
396 0 : double T = S / 36525.0;
397 0 : siderealT0 = normalize(6.697374558 + 2400.051336*T + 0.000025862*T*T, 24);
398 : }
399 0 : 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 : */
407 0 : double CalendarAstronomer::getLocalSidereal() {
408 0 : 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 : */
420 0 : double CalendarAstronomer::lstToUT(double lst) {
421 : // Convert to local mean time
422 0 : double lt = normalize((lst - getSiderealOffset()) * 0.9972695663, 24);
423 :
424 : // Then find local midnight on this day
425 0 : 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 0 : 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 : */
446 0 : CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, const CalendarAstronomer::Ecliptic& ecliptic)
447 : {
448 0 : 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 : */
461 0 : CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat)
462 : {
463 : // See page 42 of "Practial Astronomy with your Calculator",
464 : // by Peter Duffet-Smith, for details on the algorithm.
465 :
466 0 : double obliq = eclipticObliquity();
467 0 : double sinE = ::sin(obliq);
468 0 : double cosE = cos(obliq);
469 :
470 0 : double sinL = ::sin(eclipLong);
471 0 : double cosL = cos(eclipLong);
472 :
473 0 : double sinB = ::sin(eclipLat);
474 0 : double cosB = cos(eclipLat);
475 0 : double tanB = tan(eclipLat);
476 :
477 0 : result.set(atan2(sinL*cosE - tanB*sinE, cosL),
478 0 : asin(sinB*cosE + cosB*sinE*sinL) );
479 0 : 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 : */
491 0 : CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong)
492 : {
493 0 : 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 : */
500 0 : CalendarAstronomer::Horizon& CalendarAstronomer::eclipticToHorizon(CalendarAstronomer::Horizon& result, double eclipLong)
501 : {
502 0 : Equatorial equatorial;
503 0 : eclipticToEquatorial(equatorial, eclipLong);
504 :
505 0 : double H = getLocalSidereal()*CalendarAstronomer::PI/12 - equatorial.ascension; // Hour-angle
506 :
507 0 : double sinH = ::sin(H);
508 0 : double cosH = cos(H);
509 0 : double sinD = ::sin(equatorial.declination);
510 0 : double cosD = cos(equatorial.declination);
511 0 : double sinL = ::sin(fLatitude);
512 0 : double cosL = cos(fLatitude);
513 :
514 0 : double altitude = asin(sinD*sinL + cosD*cosL*cosH);
515 0 : double azimuth = atan2(-cosD*cosL*sinH, sinD - sinL * ::sin(altitude));
516 :
517 0 : result.set(azimuth, altitude);
518 0 : 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 : */
596 0 : static double trueAnomaly(double meanAnomaly, double eccentricity)
597 : {
598 : // First, solve Kepler's equation iteratively
599 : // Duffett-Smith, p.90
600 : double delta;
601 0 : double E = meanAnomaly;
602 0 : do {
603 0 : delta = E - eccentricity * ::sin(E) - meanAnomaly;
604 0 : E = E - delta / (1 - eccentricity * ::cos(E));
605 : }
606 0 : while (uprv_fabs(delta) > 1e-5); // epsilon = 1e-5 rad
607 :
608 0 : return 2.0 * ::atan( ::tan(E/2) * ::sqrt( (1+eccentricity)
609 0 : /(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 : */
624 0 : double CalendarAstronomer::getSunLongitude()
625 : {
626 : // See page 86 of "Practial Astronomy with your Calculator",
627 : // by Peter Duffet-Smith, for details on the algorithm.
628 :
629 0 : if (isINVALID(sunLongitude)) {
630 0 : getSunLongitude(getJulianDay(), sunLongitude, meanAnomalySun);
631 : }
632 0 : return sunLongitude;
633 : }
634 :
635 : /**
636 : * TODO Make this public when the entire class is package-private.
637 : */
638 0 : /*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 0 : 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 0 : 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 0 : 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 0 : longitude = norm2PI(trueAnomaly(meanAnomaly, SUN_E) + SUN_OMEGA_G);
658 0 : }
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 : */
666 0 : CalendarAstronomer::Equatorial& CalendarAstronomer::getSunPosition(CalendarAstronomer::Equatorial& result) {
667 0 : 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 : */
689 0 : double CalendarAstronomer::SUMMER_SOLSTICE() {
690 0 : 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 : */
711 0 : double CalendarAstronomer::WINTER_SOLSTICE() {
712 0 : return ((CalendarAstronomer::PI*3)/2);
713 : }
714 :
715 0 : CalendarAstronomer::AngleFunc::~AngleFunc() {}
716 :
717 : /**
718 : * Find the next time at which the sun's ecliptic longitude will have
719 : * the desired value.
720 : * @internal
721 : * @deprecated ICU 2.4. This class may be removed or modified.
722 : */
723 : class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc {
724 : public:
725 : virtual ~SunTimeAngleFunc();
726 0 : virtual double eval(CalendarAstronomer& a) { return a.getSunLongitude(); }
727 : };
728 :
729 0 : SunTimeAngleFunc::~SunTimeAngleFunc() {}
730 :
731 0 : UDate CalendarAstronomer::getSunTime(double desired, UBool next)
732 : {
733 0 : SunTimeAngleFunc func;
734 0 : return timeOfAngle( func,
735 : desired,
736 : TROPICAL_YEAR,
737 : MINUTE_MS,
738 0 : next);
739 : }
740 :
741 0 : CalendarAstronomer::CoordFunc::~CoordFunc() {}
742 :
743 : class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
744 : public:
745 : virtual ~RiseSetCoordFunc();
746 0 : virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { a.getSunPosition(result); }
747 : };
748 :
749 0 : RiseSetCoordFunc::~RiseSetCoordFunc() {}
750 :
751 0 : UDate CalendarAstronomer::getSunRiseSet(UBool rise)
752 : {
753 0 : UDate t0 = fTime;
754 :
755 : // Make a rough guess: 6am or 6pm local time on the current day
756 0 : 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 0 : 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 0 : RiseSetCoordFunc func;
763 0 : double t = riseOrSet(func,
764 : rise,
765 : .533 * DEG_RAD, // Angular Diameter
766 : 34. /60.0 * DEG_RAD, // Refraction correction
767 0 : MINUTE_MS / 12.); // Desired accuracy
768 :
769 0 : setTime(t0);
770 0 : 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 : */
1066 0 : const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition()
1067 : {
1068 : //
1069 : // See page 142 of "Practial Astronomy with your Calculator",
1070 : // by Peter Duffet-Smith, for details on the algorithm.
1071 : //
1072 0 : if (moonPositionSet == FALSE) {
1073 : // Calculate the solar longitude. Has the side effect of
1074 : // filling in "meanAnomalySun" as well.
1075 0 : 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 0 : 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 0 : double meanLongitude = norm2PI(13.1763966*PI/180*day + moonL0);
1086 0 : 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 0 : double evection = 1.2739*PI/180 * ::sin(2 * (meanLongitude - sunLongitude)
1095 0 : - meanAnomalyMoon);
1096 0 : double annual = 0.1858*PI/180 * ::sin(meanAnomalySun);
1097 0 : double a3 = 0.3700*PI/180 * ::sin(meanAnomalySun);
1098 :
1099 0 : 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 0 : double center = 6.2886*PI/180 * ::sin(meanAnomalyMoon);
1109 0 : double a4 = 0.2140*PI/180 * ::sin(2 * meanAnomalyMoon);
1110 :
1111 : // Now find the moon's corrected longitude
1112 0 : 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 0 : double variation = 0.6583*CalendarAstronomer::PI/180 * ::sin(2*(moonLongitude - sunLongitude));
1120 :
1121 0 : 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 0 : double nodeLongitude = norm2PI(moonN0 - 0.0529539*PI/180 * day);
1131 :
1132 0 : nodeLongitude -= 0.16*PI/180 * ::sin(meanAnomalySun);
1133 :
1134 0 : double y = ::sin(moonLongitude - nodeLongitude);
1135 0 : double x = cos(moonLongitude - nodeLongitude);
1136 :
1137 0 : moonEclipLong = ::atan2(y*cos(moonI), x) + nodeLongitude;
1138 0 : double moonEclipLat = ::asin(y * ::sin(moonI));
1139 :
1140 0 : eclipticToEquatorial(moonPosition, moonEclipLong, moonEclipLat);
1141 0 : moonPositionSet = TRUE;
1142 : }
1143 0 : 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 : */
1156 0 : double CalendarAstronomer::getMoonAge() {
1157 : // See page 147 of "Practial Astronomy with your Calculator",
1158 : // by Peter Duffet-Smith, for details on the algorithm.
1159 : //
1160 : // Force the moon's position to be calculated. We're going to use
1161 : // some the intermediate results cached during that calculation.
1162 : //
1163 0 : getMoonPosition();
1164 :
1165 0 : 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 : */
1183 0 : double CalendarAstronomer::getMoonPhase() {
1184 : // See page 147 of "Practial Astronomy with your Calculator",
1185 : // by Peter Duffet-Smith, for details on the algorithm.
1186 0 : 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 : */
1195 0 : const CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() {
1196 0 : 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 : */
1215 0 : const CalendarAstronomer::MoonAge CalendarAstronomer::FULL_MOON() {
1216 0 : return CalendarAstronomer::MoonAge(CalendarAstronomer::PI);
1217 : }
1218 : /**
1219 : * Constant representing the moon's last quarter.
1220 : * For use with {@link #getMoonTime getMoonTime}
1221 : * @internal
1222 : * @deprecated ICU 2.4. This class may be removed or modified.
1223 : */
1224 :
1225 : class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc {
1226 : public:
1227 : virtual ~MoonTimeAngleFunc();
1228 0 : virtual double eval(CalendarAstronomer&a) { return a.getMoonAge(); }
1229 : };
1230 :
1231 0 : MoonTimeAngleFunc::~MoonTimeAngleFunc() {}
1232 :
1233 : /*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() {
1234 : return CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2);
1235 : }*/
1236 :
1237 : /**
1238 : * Find the next or previous time at which the Moon's ecliptic
1239 : * longitude will have the desired value.
1240 : * <p>
1241 : * @param desired The desired longitude.
1242 : * @param next <tt>true</tt> if the next occurrance of the phase
1243 : * is desired, <tt>false</tt> for the previous occurrance.
1244 : * @internal
1245 : * @deprecated ICU 2.4. This class may be removed or modified.
1246 : */
1247 0 : UDate CalendarAstronomer::getMoonTime(double desired, UBool next)
1248 : {
1249 0 : MoonTimeAngleFunc func;
1250 0 : return timeOfAngle( func,
1251 : desired,
1252 : SYNODIC_MONTH,
1253 : MINUTE_MS,
1254 0 : 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 : */
1267 0 : UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) {
1268 0 : return getMoonTime(desired.value, next);
1269 : }
1270 :
1271 : class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
1272 : public:
1273 : virtual ~MoonRiseSetCoordFunc();
1274 0 : virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { result = a.getMoonPosition(); }
1275 : };
1276 :
1277 0 : MoonRiseSetCoordFunc::~MoonRiseSetCoordFunc() {}
1278 :
1279 : /**
1280 : * Returns the time (GMT) of sunrise or sunset on the local date to which
1281 : * this calendar is currently set.
1282 : * @internal
1283 : * @deprecated ICU 2.4. This class may be removed or modified.
1284 : */
1285 0 : UDate CalendarAstronomer::getMoonRiseSet(UBool rise)
1286 : {
1287 0 : MoonRiseSetCoordFunc func;
1288 0 : return riseOrSet(func,
1289 : rise,
1290 : .533 * DEG_RAD, // Angular Diameter
1291 : 34 /60.0 * DEG_RAD, // Refraction correction
1292 0 : MINUTE_MS); // Desired accuracy
1293 : }
1294 :
1295 : //-------------------------------------------------------------------------
1296 : // Interpolation methods for finding the time at which a given event occurs
1297 : //-------------------------------------------------------------------------
1298 :
1299 0 : UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired,
1300 : double periodDays, double epsilon, UBool next)
1301 : {
1302 : // Find the value of the function at the current time
1303 0 : double lastAngle = func.eval(*this);
1304 :
1305 : // Find out how far we are from the desired angle
1306 0 : 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 0 : double deltaT = (deltaAngle + (next ? 0.0 : - CalendarAstronomer_PI2 )) * (periodDays*DAY_MS) / CalendarAstronomer_PI2;
1311 :
1312 0 : double lastDeltaT = deltaT; // Liu
1313 0 : UDate startTime = fTime; // Liu
1314 :
1315 0 : 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 0 : do {
1321 : // Evaluate the function at the time we've estimated
1322 0 : double angle = func.eval(*this);
1323 :
1324 : // Find the # of milliseconds per radian at this point on the curve
1325 0 : double factor = uprv_fabs(deltaT / normPI(angle-lastAngle));
1326 :
1327 : // Correct the time estimate based on how far off the angle is
1328 0 : 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 0 : if (uprv_fabs(deltaT) > uprv_fabs(lastDeltaT)) {
1352 0 : double delta = uprv_ceil (periodDays * DAY_MS / 8.0);
1353 0 : setTime(startTime + (next ? delta : -delta));
1354 0 : return timeOfAngle(func, desired, periodDays, epsilon, next);
1355 : }
1356 :
1357 0 : lastDeltaT = deltaT;
1358 0 : lastAngle = angle;
1359 :
1360 0 : setTime(fTime + uprv_ceil(deltaT));
1361 : }
1362 0 : while (uprv_fabs(deltaT) > epsilon);
1363 :
1364 0 : return fTime;
1365 : }
1366 :
1367 0 : UDate CalendarAstronomer::riseOrSet(CoordFunc& func, UBool rise,
1368 : double diameter, double refraction,
1369 : double epsilon)
1370 : {
1371 0 : Equatorial pos;
1372 0 : double tanL = ::tan(fLatitude);
1373 0 : double deltaT = 0;
1374 0 : 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 0 : do {
1384 : // See "Practical Astronomy With Your Calculator, section 33.
1385 0 : func.eval(pos, *this);
1386 0 : double angle = ::acos(-tanL * ::tan(pos.declination));
1387 0 : double lst = ((rise ? CalendarAstronomer_PI2-angle : angle) + pos.ascension ) * 24 / CalendarAstronomer_PI2;
1388 :
1389 : // Convert from LST to Universal Time.
1390 0 : UDate newTime = lstToUT( lst );
1391 :
1392 0 : deltaT = newTime - fTime;
1393 0 : 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 0 : while (++ count < 5 && uprv_fabs(deltaT) > epsilon);
1398 :
1399 : // Calculate the correction due to refraction and the object's angular diameter
1400 0 : double cosD = ::cos(pos.declination);
1401 0 : double psi = ::acos(sin(fLatitude) / cosD);
1402 0 : double x = diameter / 2 + refraction;
1403 0 : double y = ::asin(sin(x) / ::sin(psi));
1404 0 : long delta = (long)((240 * y * RAD_DEG / cosD)*SECOND_MS);
1405 :
1406 0 : 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 : */
1416 0 : double CalendarAstronomer::eclipticObliquity() {
1417 0 : if (isINVALID(eclipObliquity)) {
1418 0 : const double epoch = 2451545.0; // 2000 AD, January 1.5
1419 :
1420 0 : double T = (getJulianDay() - epoch) / 36525;
1421 :
1422 0 : eclipObliquity = 23.439292
1423 0 : - 46.815/3600 * T
1424 0 : - 0.0006/3600 * T*T
1425 0 : + 0.00181/3600 * T*T*T;
1426 :
1427 0 : eclipObliquity *= DEG_RAD;
1428 : }
1429 0 : return eclipObliquity;
1430 : }
1431 :
1432 :
1433 : //-------------------------------------------------------------------------
1434 : // Private data
1435 : //-------------------------------------------------------------------------
1436 0 : void CalendarAstronomer::clearCache() {
1437 0 : const double INVALID = uprv_getNaN();
1438 :
1439 0 : julianDay = INVALID;
1440 0 : julianCentury = INVALID;
1441 0 : sunLongitude = INVALID;
1442 0 : meanAnomalySun = INVALID;
1443 0 : moonLongitude = INVALID;
1444 0 : moonEclipLong = INVALID;
1445 0 : meanAnomalyMoon = INVALID;
1446 0 : eclipObliquity = INVALID;
1447 0 : siderealTime = INVALID;
1448 0 : siderealT0 = INVALID;
1449 0 : moonPositionSet = FALSE;
1450 0 : }
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
1480 0 : UnicodeString CalendarAstronomer::Ecliptic::toString() const
1481 : {
1482 : #ifdef U_DEBUG_ASTRO
1483 : char tmp[800];
1484 : sprintf(tmp, "[%.5f,%.5f]", longitude*RAD_DEG, latitude*RAD_DEG);
1485 : return UnicodeString(tmp, "");
1486 : #else
1487 0 : return UnicodeString();
1488 : #endif
1489 : }
1490 :
1491 0 : UnicodeString CalendarAstronomer::Equatorial::toString() const
1492 : {
1493 : #ifdef U_DEBUG_ASTRO
1494 : char tmp[400];
1495 : sprintf(tmp, "%f,%f",
1496 : (ascension*RAD_DEG), (declination*RAD_DEG));
1497 : return UnicodeString(tmp, "");
1498 : #else
1499 0 : return UnicodeString();
1500 : #endif
1501 : }
1502 :
1503 0 : UnicodeString CalendarAstronomer::Horizon::toString() const
1504 : {
1505 : #ifdef U_DEBUG_ASTRO
1506 : char tmp[800];
1507 : sprintf(tmp, "[%.5f,%.5f]", altitude*RAD_DEG, azimuth*RAD_DEG);
1508 : return UnicodeString(tmp, "");
1509 : #else
1510 0 : 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 :
1533 0 : void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) {
1534 0 : ucln_i18n_registerCleanup(UCLN_I18N_ASTRO_CALENDAR, calendar_astro_cleanup);
1535 0 : if(cache == NULL) {
1536 0 : status = U_MEMORY_ALLOCATION_ERROR;
1537 : } else {
1538 0 : *cache = new CalendarCache(32, status);
1539 0 : if(U_FAILURE(status)) {
1540 0 : delete *cache;
1541 0 : *cache = NULL;
1542 : }
1543 : }
1544 0 : }
1545 :
1546 0 : int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) {
1547 : int32_t res;
1548 :
1549 0 : if(U_FAILURE(status)) {
1550 0 : return 0;
1551 : }
1552 0 : umtx_lock(&ccLock);
1553 :
1554 0 : if(*cache == NULL) {
1555 0 : createCache(cache, status);
1556 0 : if(U_FAILURE(status)) {
1557 0 : umtx_unlock(&ccLock);
1558 0 : return 0;
1559 : }
1560 : }
1561 :
1562 0 : res = uhash_igeti((*cache)->fTable, key);
1563 : U_DEBUG_ASTRO_MSG(("%p: GET: [%d] == %d\n", (*cache)->fTable, key, res));
1564 :
1565 0 : umtx_unlock(&ccLock);
1566 0 : return res;
1567 : }
1568 :
1569 0 : void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) {
1570 0 : if(U_FAILURE(status)) {
1571 0 : return;
1572 : }
1573 0 : umtx_lock(&ccLock);
1574 :
1575 0 : if(*cache == NULL) {
1576 0 : createCache(cache, status);
1577 0 : if(U_FAILURE(status)) {
1578 0 : umtx_unlock(&ccLock);
1579 0 : return;
1580 : }
1581 : }
1582 :
1583 0 : uhash_iputi((*cache)->fTable, key, value, &status);
1584 : U_DEBUG_ASTRO_MSG(("%p: PUT: [%d] := %d\n", (*cache)->fTable, key, value));
1585 :
1586 0 : umtx_unlock(&ccLock);
1587 : }
1588 :
1589 0 : CalendarCache::CalendarCache(int32_t size, UErrorCode &status) {
1590 0 : fTable = uhash_openSize(uhash_hashLong, uhash_compareLong, NULL, size, &status);
1591 : U_DEBUG_ASTRO_MSG(("%p: Opening.\n", fTable));
1592 0 : }
1593 :
1594 0 : CalendarCache::~CalendarCache() {
1595 0 : if(fTable != NULL) {
1596 : U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable));
1597 0 : uhash_close(fTable);
1598 : }
1599 0 : }
1600 :
1601 : U_NAMESPACE_END
1602 :
1603 : #endif // !UCONFIG_NO_FORMATTING
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