1 /************************************************************************
2 * Copyright (C) 1996-2008, 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
debug_astro_loc(const char * f,int32_t l)29 static void debug_astro_loc(const char *f, int32_t l)
30 {
31 fprintf(stderr, "%s:%d: ", f, l);
32 }
33
debug_astro_msg(const char * pat,...)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"
debug_astro_date(UDate d)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
isINVALID(double d)62 static inline UBool isINVALID(double d) {
63 return(uprv_isNaN(d));
64 }
65
66 static UMTX ccLock = NULL;
67
68 U_CDECL_BEGIN
calendar_astro_cleanup(void)69 static UBool calendar_astro_cleanup(void) {
70 umtx_destroy(&ccLock);
71 return TRUE;
72 }
73 U_CDECL_END
74
75 U_NAMESPACE_BEGIN
76
77 /**
78 * The number of standard hours in one sidereal day.
79 * Approximately 24.93.
80 * @internal
81 * @deprecated ICU 2.4. This class may be removed or modified.
82 */
83 #define SIDEREAL_DAY (23.93446960027)
84
85 /**
86 * The number of sidereal hours in one mean solar day.
87 * Approximately 24.07.
88 * @internal
89 * @deprecated ICU 2.4. This class may be removed or modified.
90 */
91 #define SOLAR_DAY (24.065709816)
92
93 /**
94 * The average number of solar days from one new moon to the next. This is the time
95 * it takes for the moon to return the same ecliptic longitude as the sun.
96 * It is longer than the sidereal month because the sun's longitude increases
97 * during the year due to the revolution of the earth around the sun.
98 * Approximately 29.53.
99 *
100 * @see #SIDEREAL_MONTH
101 * @internal
102 * @deprecated ICU 2.4. This class may be removed or modified.
103 */
104 const double CalendarAstronomer::SYNODIC_MONTH = 29.530588853;
105
106 /**
107 * The average number of days it takes
108 * for the moon to return to the same ecliptic longitude relative to the
109 * stellar background. This is referred to as the sidereal month.
110 * It is shorter than the synodic month due to
111 * the revolution of the earth around the sun.
112 * Approximately 27.32.
113 *
114 * @see #SYNODIC_MONTH
115 * @internal
116 * @deprecated ICU 2.4. This class may be removed or modified.
117 */
118 #define SIDEREAL_MONTH 27.32166
119
120 /**
121 * The average number number of days between successive vernal equinoxes.
122 * Due to the precession of the earth's
123 * axis, this is not precisely the same as the sidereal year.
124 * Approximately 365.24
125 *
126 * @see #SIDEREAL_YEAR
127 * @internal
128 * @deprecated ICU 2.4. This class may be removed or modified.
129 */
130 #define TROPICAL_YEAR 365.242191
131
132 /**
133 * The average number of days it takes
134 * for the sun to return to the same position against the fixed stellar
135 * background. This is the duration of one orbit of the earth about the sun
136 * as it would appear to an outside observer.
137 * Due to the precession of the earth's
138 * axis, this is not precisely the same as the tropical year.
139 * Approximately 365.25.
140 *
141 * @see #TROPICAL_YEAR
142 * @internal
143 * @deprecated ICU 2.4. This class may be removed or modified.
144 */
145 #define SIDEREAL_YEAR 365.25636
146
147 //-------------------------------------------------------------------------
148 // Time-related constants
149 //-------------------------------------------------------------------------
150
151 /**
152 * The number of milliseconds in one second.
153 * @internal
154 * @deprecated ICU 2.4. This class may be removed or modified.
155 */
156 #define SECOND_MS U_MILLIS_PER_SECOND
157
158 /**
159 * The number of milliseconds in one minute.
160 * @internal
161 * @deprecated ICU 2.4. This class may be removed or modified.
162 */
163 #define MINUTE_MS U_MILLIS_PER_MINUTE
164
165 /**
166 * The number of milliseconds in one hour.
167 * @internal
168 * @deprecated ICU 2.4. This class may be removed or modified.
169 */
170 #define HOUR_MS U_MILLIS_PER_HOUR
171
172 /**
173 * The number of milliseconds in one day.
174 * @internal
175 * @deprecated ICU 2.4. This class may be removed or modified.
176 */
177 #define DAY_MS U_MILLIS_PER_DAY
178
179 /**
180 * The start of the julian day numbering scheme used by astronomers, which
181 * is 1/1/4713 BC (Julian), 12:00 GMT. This is given as the number of milliseconds
182 * since 1/1/1970 AD (Gregorian), a negative number.
183 * Note that julian day numbers and
184 * the Julian calendar are <em>not</em> the same thing. Also note that
185 * julian days start at <em>noon</em>, not midnight.
186 * @internal
187 * @deprecated ICU 2.4. This class may be removed or modified.
188 */
189 #define JULIAN_EPOCH_MS -210866760000000.0
190
191
192 /**
193 * Milliseconds value for 0.0 January 2000 AD.
194 */
195 #define EPOCH_2000_MS 946598400000.0
196
197 //-------------------------------------------------------------------------
198 // Assorted private data used for conversions
199 //-------------------------------------------------------------------------
200
201 // My own copies of these so compilers are more likely to optimize them away
202 const double CalendarAstronomer::PI = 3.14159265358979323846;
203
204 #define CalendarAstronomer_PI2 (CalendarAstronomer::PI*2.0)
205 #define RAD_HOUR ( 12 / CalendarAstronomer::PI ) // radians -> hours
206 #define DEG_RAD ( CalendarAstronomer::PI / 180 ) // degrees -> radians
207 #define RAD_DEG ( 180 / CalendarAstronomer::PI ) // radians -> degrees
208
209 /***
210 * Given 'value', add or subtract 'range' until 0 <= 'value' < range.
211 * The modulus operator.
212 */
normalize(double value,double range)213 inline static double normalize(double value, double range) {
214 return value - range * ClockMath::floorDivide(value, range);
215 }
216
217 /**
218 * Normalize an angle so that it's in the range 0 - 2pi.
219 * For positive angles this is just (angle % 2pi), but the Java
220 * mod operator doesn't work that way for negative numbers....
221 */
norm2PI(double angle)222 inline static double norm2PI(double angle) {
223 return normalize(angle, CalendarAstronomer::PI * 2.0);
224 }
225
226 /**
227 * Normalize an angle into the range -PI - PI
228 */
normPI(double angle)229 inline static double normPI(double angle) {
230 return normalize(angle + CalendarAstronomer::PI, CalendarAstronomer::PI * 2.0) - CalendarAstronomer::PI;
231 }
232
233 //-------------------------------------------------------------------------
234 // Constructors
235 //-------------------------------------------------------------------------
236
237 /**
238 * Construct a new <code>CalendarAstronomer</code> object that is initialized to
239 * the current date and time.
240 * @internal
241 * @deprecated ICU 2.4. This class may be removed or modified.
242 */
CalendarAstronomer()243 CalendarAstronomer::CalendarAstronomer():
244 fTime(Calendar::getNow()), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
245 clearCache();
246 }
247
248 /**
249 * Construct a new <code>CalendarAstronomer</code> object that is initialized to
250 * the specified date and time.
251 * @internal
252 * @deprecated ICU 2.4. This class may be removed or modified.
253 */
CalendarAstronomer(UDate d)254 CalendarAstronomer::CalendarAstronomer(UDate d): fTime(d), fLongitude(0.0), fLatitude(0.0), fGmtOffset(0.0), moonPosition(0,0), moonPositionSet(FALSE) {
255 clearCache();
256 }
257
258 /**
259 * Construct a new <code>CalendarAstronomer</code> object with the given
260 * latitude and longitude. The object's time is set to the current
261 * date and time.
262 * <p>
263 * @param longitude The desired longitude, in <em>degrees</em> east of
264 * the Greenwich meridian.
265 *
266 * @param latitude The desired latitude, in <em>degrees</em>. Positive
267 * values signify North, negative South.
268 *
269 * @see java.util.Date#getTime()
270 * @internal
271 * @deprecated ICU 2.4. This class may be removed or modified.
272 */
CalendarAstronomer(double longitude,double latitude)273 CalendarAstronomer::CalendarAstronomer(double longitude, double latitude) :
274 fTime(Calendar::getNow()), moonPosition(0,0), moonPositionSet(FALSE) {
275 fLongitude = normPI(longitude * (double)DEG_RAD);
276 fLatitude = normPI(latitude * (double)DEG_RAD);
277 fGmtOffset = (double)(fLongitude * 24. * (double)HOUR_MS / (double)CalendarAstronomer_PI2);
278 clearCache();
279 }
280
~CalendarAstronomer()281 CalendarAstronomer::~CalendarAstronomer()
282 {
283 }
284
285 //-------------------------------------------------------------------------
286 // Time and date getters and setters
287 //-------------------------------------------------------------------------
288
289 /**
290 * Set the current date and time of this <code>CalendarAstronomer</code> object. All
291 * astronomical calculations are performed based on this time setting.
292 *
293 * @param aTime the date and time, expressed as the number of milliseconds since
294 * 1/1/1970 0:00 GMT (Gregorian).
295 *
296 * @see #setDate
297 * @see #getTime
298 * @internal
299 * @deprecated ICU 2.4. This class may be removed or modified.
300 */
setTime(UDate aTime)301 void CalendarAstronomer::setTime(UDate aTime) {
302 fTime = aTime;
303 U_DEBUG_ASTRO_MSG(("setTime(%.1lf, %sL)\n", aTime, debug_astro_date(aTime+fGmtOffset)));
304 clearCache();
305 }
306
307 /**
308 * Set the current date and time of this <code>CalendarAstronomer</code> object. All
309 * astronomical calculations are performed based on this time setting.
310 *
311 * @param jdn the desired time, expressed as a "julian day number",
312 * which is the number of elapsed days since
313 * 1/1/4713 BC (Julian), 12:00 GMT. Note that julian day
314 * numbers start at <em>noon</em>. To get the jdn for
315 * the corresponding midnight, subtract 0.5.
316 *
317 * @see #getJulianDay
318 * @see #JULIAN_EPOCH_MS
319 * @internal
320 * @deprecated ICU 2.4. This class may be removed or modified.
321 */
setJulianDay(double jdn)322 void CalendarAstronomer::setJulianDay(double jdn) {
323 fTime = (double)(jdn * DAY_MS) + JULIAN_EPOCH_MS;
324 clearCache();
325 julianDay = jdn;
326 }
327
328 /**
329 * Get the current time of this <code>CalendarAstronomer</code> object,
330 * represented as the number of milliseconds since
331 * 1/1/1970 AD 0:00 GMT (Gregorian).
332 *
333 * @see #setTime
334 * @see #getDate
335 * @internal
336 * @deprecated ICU 2.4. This class may be removed or modified.
337 */
getTime()338 UDate CalendarAstronomer::getTime() {
339 return fTime;
340 }
341
342 /**
343 * Get the current time of this <code>CalendarAstronomer</code> object,
344 * expressed as a "julian day number", which is the number of elapsed
345 * days since 1/1/4713 BC (Julian), 12:00 GMT.
346 *
347 * @see #setJulianDay
348 * @see #JULIAN_EPOCH_MS
349 * @internal
350 * @deprecated ICU 2.4. This class may be removed or modified.
351 */
getJulianDay()352 double CalendarAstronomer::getJulianDay() {
353 if (isINVALID(julianDay)) {
354 julianDay = (fTime - (double)JULIAN_EPOCH_MS) / (double)DAY_MS;
355 }
356 return julianDay;
357 }
358
359 /**
360 * Return this object's time expressed in julian centuries:
361 * the number of centuries after 1/1/1900 AD, 12:00 GMT
362 *
363 * @see #getJulianDay
364 * @internal
365 * @deprecated ICU 2.4. This class may be removed or modified.
366 */
getJulianCentury()367 double CalendarAstronomer::getJulianCentury() {
368 if (isINVALID(julianCentury)) {
369 julianCentury = (getJulianDay() - 2415020.0) / 36525.0;
370 }
371 return julianCentury;
372 }
373
374 /**
375 * Returns the current Greenwich sidereal time, measured in hours
376 * @internal
377 * @deprecated ICU 2.4. This class may be removed or modified.
378 */
getGreenwichSidereal()379 double CalendarAstronomer::getGreenwichSidereal() {
380 if (isINVALID(siderealTime)) {
381 // See page 86 of "Practial Astronomy with your Calculator",
382 // by Peter Duffet-Smith, for details on the algorithm.
383
384 double UT = normalize(fTime/(double)HOUR_MS, 24.);
385
386 siderealTime = normalize(getSiderealOffset() + UT*1.002737909, 24.);
387 }
388 return siderealTime;
389 }
390
getSiderealOffset()391 double CalendarAstronomer::getSiderealOffset() {
392 if (isINVALID(siderealT0)) {
393 double JD = uprv_floor(getJulianDay() - 0.5) + 0.5;
394 double S = JD - 2451545.0;
395 double T = S / 36525.0;
396 siderealT0 = normalize(6.697374558 + 2400.051336*T + 0.000025862*T*T, 24);
397 }
398 return siderealT0;
399 }
400
401 /**
402 * Returns the current local sidereal time, measured in hours
403 * @internal
404 * @deprecated ICU 2.4. This class may be removed or modified.
405 */
getLocalSidereal()406 double CalendarAstronomer::getLocalSidereal() {
407 return normalize(getGreenwichSidereal() + (fGmtOffset/(double)HOUR_MS), 24.);
408 }
409
410 /**
411 * Converts local sidereal time to Universal Time.
412 *
413 * @param lst The Local Sidereal Time, in hours since sidereal midnight
414 * on this object's current date.
415 *
416 * @return The corresponding Universal Time, in milliseconds since
417 * 1 Jan 1970, GMT.
418 */
lstToUT(double lst)419 double CalendarAstronomer::lstToUT(double lst) {
420 // Convert to local mean time
421 double lt = normalize((lst - getSiderealOffset()) * 0.9972695663, 24);
422
423 // Then find local midnight on this day
424 double base = (DAY_MS * ClockMath::floorDivide(fTime + fGmtOffset,(double)DAY_MS)) - fGmtOffset;
425
426 //out(" lt =" + lt + " hours");
427 //out(" base=" + new Date(base));
428
429 return base + (long)(lt * HOUR_MS);
430 }
431
432
433 //-------------------------------------------------------------------------
434 // Coordinate transformations, all based on the current time of this object
435 //-------------------------------------------------------------------------
436
437 /**
438 * Convert from ecliptic to equatorial coordinates.
439 *
440 * @param ecliptic A point in the sky in ecliptic coordinates.
441 * @return The corresponding point in equatorial coordinates.
442 * @internal
443 * @deprecated ICU 2.4. This class may be removed or modified.
444 */
eclipticToEquatorial(CalendarAstronomer::Equatorial & result,const CalendarAstronomer::Ecliptic & ecliptic)445 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, const CalendarAstronomer::Ecliptic& ecliptic)
446 {
447 return eclipticToEquatorial(result, ecliptic.longitude, ecliptic.latitude);
448 }
449
450 /**
451 * Convert from ecliptic to equatorial coordinates.
452 *
453 * @param eclipLong The ecliptic longitude
454 * @param eclipLat The ecliptic latitude
455 *
456 * @return The corresponding point in equatorial coordinates.
457 * @internal
458 * @deprecated ICU 2.4. This class may be removed or modified.
459 */
eclipticToEquatorial(CalendarAstronomer::Equatorial & result,double eclipLong,double eclipLat)460 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat)
461 {
462 // See page 42 of "Practial Astronomy with your Calculator",
463 // by Peter Duffet-Smith, for details on the algorithm.
464
465 double obliq = eclipticObliquity();
466 double sinE = ::sin(obliq);
467 double cosE = cos(obliq);
468
469 double sinL = ::sin(eclipLong);
470 double cosL = cos(eclipLong);
471
472 double sinB = ::sin(eclipLat);
473 double cosB = cos(eclipLat);
474 double tanB = tan(eclipLat);
475
476 result.set(atan2(sinL*cosE - tanB*sinE, cosL),
477 asin(sinB*cosE + cosB*sinE*sinL) );
478 return result;
479 }
480
481 /**
482 * Convert from ecliptic longitude to equatorial coordinates.
483 *
484 * @param eclipLong The ecliptic longitude
485 *
486 * @return The corresponding point in equatorial coordinates.
487 * @internal
488 * @deprecated ICU 2.4. This class may be removed or modified.
489 */
eclipticToEquatorial(CalendarAstronomer::Equatorial & result,double eclipLong)490 CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong)
491 {
492 return eclipticToEquatorial(result, eclipLong, 0); // TODO: optimize
493 }
494
495 /**
496 * @internal
497 * @deprecated ICU 2.4. This class may be removed or modified.
498 */
eclipticToHorizon(CalendarAstronomer::Horizon & result,double eclipLong)499 CalendarAstronomer::Horizon& CalendarAstronomer::eclipticToHorizon(CalendarAstronomer::Horizon& result, double eclipLong)
500 {
501 Equatorial equatorial;
502 eclipticToEquatorial(equatorial, eclipLong);
503
504 double H = getLocalSidereal()*CalendarAstronomer::PI/12 - equatorial.ascension; // Hour-angle
505
506 double sinH = ::sin(H);
507 double cosH = cos(H);
508 double sinD = ::sin(equatorial.declination);
509 double cosD = cos(equatorial.declination);
510 double sinL = ::sin(fLatitude);
511 double cosL = cos(fLatitude);
512
513 double altitude = asin(sinD*sinL + cosD*cosL*cosH);
514 double azimuth = atan2(-cosD*cosL*sinH, sinD - sinL * ::sin(altitude));
515
516 result.set(azimuth, altitude);
517 return result;
518 }
519
520
521 //-------------------------------------------------------------------------
522 // The Sun
523 //-------------------------------------------------------------------------
524
525 //
526 // Parameters of the Sun's orbit as of the epoch Jan 0.0 1990
527 // Angles are in radians (after multiplying by CalendarAstronomer::PI/180)
528 //
529 #define JD_EPOCH 2447891.5 // Julian day of epoch
530
531 #define SUN_ETA_G (279.403303 * CalendarAstronomer::PI/180) // Ecliptic longitude at epoch
532 #define SUN_OMEGA_G (282.768422 * CalendarAstronomer::PI/180) // Ecliptic longitude of perigee
533 #define SUN_E 0.016713 // Eccentricity of orbit
534 //double sunR0 1.495585e8 // Semi-major axis in KM
535 //double sunTheta0 (0.533128 * CalendarAstronomer::PI/180) // Angular diameter at R0
536
537 // The following three methods, which compute the sun parameters
538 // given above for an arbitrary epoch (whatever time the object is
539 // set to), make only a small difference as compared to using the
540 // above constants. E.g., Sunset times might differ by ~12
541 // seconds. Furthermore, the eta-g computation is befuddled by
542 // Duffet-Smith's incorrect coefficients (p.86). I've corrected
543 // the first-order coefficient but the others may be off too - no
544 // way of knowing without consulting another source.
545
546 // /**
547 // * Return the sun's ecliptic longitude at perigee for the current time.
548 // * See Duffett-Smith, p. 86.
549 // * @return radians
550 // */
551 // private double getSunOmegaG() {
552 // double T = getJulianCentury();
553 // return (281.2208444 + (1.719175 + 0.000452778*T)*T) * DEG_RAD;
554 // }
555
556 // /**
557 // * Return the sun's ecliptic longitude for the current time.
558 // * See Duffett-Smith, p. 86.
559 // * @return radians
560 // */
561 // private double getSunEtaG() {
562 // double T = getJulianCentury();
563 // //return (279.6966778 + (36000.76892 + 0.0003025*T)*T) * DEG_RAD;
564 // //
565 // // The above line is from Duffett-Smith, and yields manifestly wrong
566 // // results. The below constant is derived empirically to match the
567 // // constant he gives for the 1990 EPOCH.
568 // //
569 // return (279.6966778 + (-0.3262541582718024 + 0.0003025*T)*T) * DEG_RAD;
570 // }
571
572 // /**
573 // * Return the sun's eccentricity of orbit for the current time.
574 // * See Duffett-Smith, p. 86.
575 // * @return double
576 // */
577 // private double getSunE() {
578 // double T = getJulianCentury();
579 // return 0.01675104 - (0.0000418 + 0.000000126*T)*T;
580 // }
581
582 /**
583 * Find the "true anomaly" (longitude) of an object from
584 * its mean anomaly and the eccentricity of its orbit. This uses
585 * an iterative solution to Kepler's equation.
586 *
587 * @param meanAnomaly The object's longitude calculated as if it were in
588 * a regular, circular orbit, measured in radians
589 * from the point of perigee.
590 *
591 * @param eccentricity The eccentricity of the orbit
592 *
593 * @return The true anomaly (longitude) measured in radians
594 */
trueAnomaly(double meanAnomaly,double eccentricity)595 static double trueAnomaly(double meanAnomaly, double eccentricity)
596 {
597 // First, solve Kepler's equation iteratively
598 // Duffett-Smith, p.90
599 double delta;
600 double E = meanAnomaly;
601 do {
602 delta = E - eccentricity * ::sin(E) - meanAnomaly;
603 E = E - delta / (1 - eccentricity * ::cos(E));
604 }
605 while (uprv_fabs(delta) > 1e-5); // epsilon = 1e-5 rad
606
607 return 2.0 * ::atan( ::tan(E/2) * ::sqrt( (1+eccentricity)
608 /(1-eccentricity) ) );
609 }
610
611 /**
612 * The longitude of the sun at the time specified by this object.
613 * The longitude is measured in radians along the ecliptic
614 * from the "first point of Aries," the point at which the ecliptic
615 * crosses the earth's equatorial plane at the vernal equinox.
616 * <p>
617 * Currently, this method uses an approximation of the two-body Kepler's
618 * equation for the earth and the sun. It does not take into account the
619 * perturbations caused by the other planets, the moon, etc.
620 * @internal
621 * @deprecated ICU 2.4. This class may be removed or modified.
622 */
getSunLongitude()623 double CalendarAstronomer::getSunLongitude()
624 {
625 // See page 86 of "Practial Astronomy with your Calculator",
626 // by Peter Duffet-Smith, for details on the algorithm.
627
628 if (isINVALID(sunLongitude)) {
629 getSunLongitude(getJulianDay(), sunLongitude, meanAnomalySun);
630 }
631 return sunLongitude;
632 }
633
634 /**
635 * TODO Make this public when the entire class is package-private.
636 */
getSunLongitude(double jDay,double & longitude,double & meanAnomaly)637 /*public*/ void CalendarAstronomer::getSunLongitude(double jDay, double &longitude, double &meanAnomaly)
638 {
639 // See page 86 of "Practial Astronomy with your Calculator",
640 // by Peter Duffet-Smith, for details on the algorithm.
641
642 double day = jDay - JD_EPOCH; // Days since epoch
643
644 // Find the angular distance the sun in a fictitious
645 // circular orbit has travelled since the epoch.
646 double epochAngle = norm2PI(CalendarAstronomer_PI2/TROPICAL_YEAR*day);
647
648 // The epoch wasn't at the sun's perigee; find the angular distance
649 // since perigee, which is called the "mean anomaly"
650 meanAnomaly = norm2PI(epochAngle + SUN_ETA_G - SUN_OMEGA_G);
651
652 // Now find the "true anomaly", e.g. the real solar longitude
653 // by solving Kepler's equation for an elliptical orbit
654 // NOTE: The 3rd ed. of the book lists omega_g and eta_g in different
655 // equations; omega_g is to be correct.
656 longitude = norm2PI(trueAnomaly(meanAnomaly, SUN_E) + SUN_OMEGA_G);
657 }
658
659 /**
660 * The position of the sun at this object's current date and time,
661 * in equatorial coordinates.
662 * @internal
663 * @deprecated ICU 2.4. This class may be removed or modified.
664 */
getSunPosition(CalendarAstronomer::Equatorial & result)665 CalendarAstronomer::Equatorial& CalendarAstronomer::getSunPosition(CalendarAstronomer::Equatorial& result) {
666 return eclipticToEquatorial(result, getSunLongitude(), 0);
667 }
668
669
670 /**
671 * Constant representing the vernal equinox.
672 * For use with {@link #getSunTime getSunTime}.
673 * Note: In this case, "vernal" refers to the northern hemisphere's seasons.
674 * @internal
675 * @deprecated ICU 2.4. This class may be removed or modified.
676 */
677 /*double CalendarAstronomer::VERNAL_EQUINOX() {
678 return 0;
679 }*/
680
681 /**
682 * Constant representing the summer solstice.
683 * For use with {@link #getSunTime getSunTime}.
684 * Note: In this case, "summer" refers to the northern hemisphere's seasons.
685 * @internal
686 * @deprecated ICU 2.4. This class may be removed or modified.
687 */
SUMMER_SOLSTICE()688 double CalendarAstronomer::SUMMER_SOLSTICE() {
689 return (CalendarAstronomer::PI/2);
690 }
691
692 /**
693 * Constant representing the autumnal equinox.
694 * For use with {@link #getSunTime getSunTime}.
695 * Note: In this case, "autumn" refers to the northern hemisphere's seasons.
696 * @internal
697 * @deprecated ICU 2.4. This class may be removed or modified.
698 */
699 /*double CalendarAstronomer::AUTUMN_EQUINOX() {
700 return (CalendarAstronomer::PI);
701 }*/
702
703 /**
704 * Constant representing the winter solstice.
705 * For use with {@link #getSunTime getSunTime}.
706 * Note: In this case, "winter" refers to the northern hemisphere's seasons.
707 * @internal
708 * @deprecated ICU 2.4. This class may be removed or modified.
709 */
WINTER_SOLSTICE()710 double CalendarAstronomer::WINTER_SOLSTICE() {
711 return ((CalendarAstronomer::PI*3)/2);
712 }
713
~AngleFunc()714 CalendarAstronomer::AngleFunc::~AngleFunc() {}
715
716 /**
717 * Find the next time at which the sun's ecliptic longitude will have
718 * the desired value.
719 * @internal
720 * @deprecated ICU 2.4. This class may be removed or modified.
721 */
722 class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc {
723 public:
eval(CalendarAstronomer & a)724 virtual double eval(CalendarAstronomer& a) { return a.getSunLongitude(); }
725 };
726
getSunTime(double desired,UBool next)727 UDate CalendarAstronomer::getSunTime(double desired, UBool next)
728 {
729 SunTimeAngleFunc func;
730 return timeOfAngle( func,
731 desired,
732 TROPICAL_YEAR,
733 MINUTE_MS,
734 next);
735 }
736
~CoordFunc()737 CalendarAstronomer::CoordFunc::~CoordFunc() {}
738
739 class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
740 public:
eval(CalendarAstronomer::Equatorial & result,CalendarAstronomer & a)741 virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { a.getSunPosition(result); }
742 };
743
getSunRiseSet(UBool rise)744 UDate CalendarAstronomer::getSunRiseSet(UBool rise)
745 {
746 UDate t0 = fTime;
747
748 // Make a rough guess: 6am or 6pm local time on the current day
749 double noon = ClockMath::floorDivide(fTime + fGmtOffset, (double)DAY_MS)*DAY_MS - fGmtOffset + (12*HOUR_MS);
750
751 U_DEBUG_ASTRO_MSG(("Noon=%.2lf, %sL, gmtoff %.2lf\n", noon, debug_astro_date(noon+fGmtOffset), fGmtOffset));
752 setTime(noon + ((rise ? -6 : 6) * HOUR_MS));
753 U_DEBUG_ASTRO_MSG(("added %.2lf ms as a guess,\n", ((rise ? -6. : 6.) * HOUR_MS)));
754
755 RiseSetCoordFunc func;
756 double t = riseOrSet(func,
757 rise,
758 .533 * DEG_RAD, // Angular Diameter
759 34. /60.0 * DEG_RAD, // Refraction correction
760 MINUTE_MS / 12.); // Desired accuracy
761
762 setTime(t0);
763 return t;
764 }
765
766 // Commented out - currently unused. ICU 2.6, Alan
767 // //-------------------------------------------------------------------------
768 // // Alternate Sun Rise/Set
769 // // See Duffett-Smith p.93
770 // //-------------------------------------------------------------------------
771 //
772 // // This yields worse results (as compared to USNO data) than getSunRiseSet().
773 // /**
774 // * TODO Make this when the entire class is package-private.
775 // */
776 // /*public*/ long getSunRiseSet2(boolean rise) {
777 // // 1. Calculate coordinates of the sun's center for midnight
778 // double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
779 // double[] sl = getSunLongitude(jd);// double lambda1 = sl[0];
780 // Equatorial pos1 = eclipticToEquatorial(lambda1, 0);
781 //
782 // // 2. Add ... to lambda to get position 24 hours later
783 // double lambda2 = lambda1 + 0.985647*DEG_RAD;
784 // Equatorial pos2 = eclipticToEquatorial(lambda2, 0);
785 //
786 // // 3. Calculate LSTs of rising and setting for these two positions
787 // double tanL = ::tan(fLatitude);
788 // double H = ::acos(-tanL * ::tan(pos1.declination));
789 // double lst1r = (CalendarAstronomer_PI2 + pos1.ascension - H) * 24 / CalendarAstronomer_PI2;
790 // double lst1s = (pos1.ascension + H) * 24 / CalendarAstronomer_PI2;
791 // H = ::acos(-tanL * ::tan(pos2.declination));
792 // double lst2r = (CalendarAstronomer_PI2-H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
793 // double lst2s = (H + pos2.ascension ) * 24 / CalendarAstronomer_PI2;
794 // if (lst1r > 24) lst1r -= 24;
795 // if (lst1s > 24) lst1s -= 24;
796 // if (lst2r > 24) lst2r -= 24;
797 // if (lst2s > 24) lst2s -= 24;
798 //
799 // // 4. Convert LSTs to GSTs. If GST1 > GST2, add 24 to GST2.
800 // double gst1r = lstToGst(lst1r);
801 // double gst1s = lstToGst(lst1s);
802 // double gst2r = lstToGst(lst2r);
803 // double gst2s = lstToGst(lst2s);
804 // if (gst1r > gst2r) gst2r += 24;
805 // if (gst1s > gst2s) gst2s += 24;
806 //
807 // // 5. Calculate GST at 0h UT of this date
808 // double t00 = utToGst(0);
809 //
810 // // 6. Calculate GST at 0h on the observer's longitude
811 // double offset = ::round(fLongitude*12/PI); // p.95 step 6; he _rounds_ to nearest 15 deg.
812 // double t00p = t00 - offset*1.002737909;
813 // if (t00p < 0) t00p += 24; // do NOT normalize
814 //
815 // // 7. Adjust
816 // if (gst1r < t00p) {
817 // gst1r += 24;
818 // gst2r += 24;
819 // }
820 // if (gst1s < t00p) {
821 // gst1s += 24;
822 // gst2s += 24;
823 // }
824 //
825 // // 8.
826 // double gstr = (24.07*gst1r-t00*(gst2r-gst1r))/(24.07+gst1r-gst2r);
827 // double gsts = (24.07*gst1s-t00*(gst2s-gst1s))/(24.07+gst1s-gst2s);
828 //
829 // // 9. Correct for parallax, refraction, and sun's diameter
830 // double dec = (pos1.declination + pos2.declination) / 2;
831 // double psi = ::acos(sin(fLatitude) / cos(dec));
832 // double x = 0.830725 * DEG_RAD; // parallax+refraction+diameter
833 // double y = ::asin(sin(x) / ::sin(psi)) * RAD_DEG;
834 // double delta_t = 240 * y / cos(dec) / 3600; // hours
835 //
836 // // 10. Add correction to GSTs, subtract from GSTr
837 // gstr -= delta_t;
838 // gsts += delta_t;
839 //
840 // // 11. Convert GST to UT and then to local civil time
841 // double ut = gstToUt(rise ? gstr : gsts);
842 // //System.out.println((rise?"rise=":"set=") + ut + ", delta_t=" + delta_t);
843 // long midnight = DAY_MS * (time / DAY_MS); // Find UT midnight on this day
844 // return midnight + (long) (ut * 3600000);
845 // }
846
847 // Commented out - currently unused. ICU 2.6, Alan
848 // /**
849 // * Convert local sidereal time to Greenwich sidereal time.
850 // * Section 15. Duffett-Smith p.21
851 // * @param lst in hours (0..24)
852 // * @return GST in hours (0..24)
853 // */
854 // double lstToGst(double lst) {
855 // double delta = fLongitude * 24 / CalendarAstronomer_PI2;
856 // return normalize(lst - delta, 24);
857 // }
858
859 // Commented out - currently unused. ICU 2.6, Alan
860 // /**
861 // * Convert UT to GST on this date.
862 // * Section 12. Duffett-Smith p.17
863 // * @param ut in hours
864 // * @return GST in hours
865 // */
866 // double utToGst(double ut) {
867 // return normalize(getT0() + ut*1.002737909, 24);
868 // }
869
870 // Commented out - currently unused. ICU 2.6, Alan
871 // /**
872 // * Convert GST to UT on this date.
873 // * Section 13. Duffett-Smith p.18
874 // * @param gst in hours
875 // * @return UT in hours
876 // */
877 // double gstToUt(double gst) {
878 // return normalize(gst - getT0(), 24) * 0.9972695663;
879 // }
880
881 // Commented out - currently unused. ICU 2.6, Alan
882 // double getT0() {
883 // // Common computation for UT <=> GST
884 //
885 // // Find JD for 0h UT
886 // double jd = uprv_floor(getJulianDay() - 0.5) + 0.5;
887 //
888 // double s = jd - 2451545.0;
889 // double t = s / 36525.0;
890 // double t0 = 6.697374558 + (2400.051336 + 0.000025862*t)*t;
891 // return t0;
892 // }
893
894 // Commented out - currently unused. ICU 2.6, Alan
895 // //-------------------------------------------------------------------------
896 // // Alternate Sun Rise/Set
897 // // See sci.astro FAQ
898 // // http://www.faqs.org/faqs/astronomy/faq/part3/section-5.html
899 // //-------------------------------------------------------------------------
900 //
901 // // Note: This method appears to produce inferior accuracy as
902 // // compared to getSunRiseSet().
903 //
904 // /**
905 // * TODO Make this when the entire class is package-private.
906 // */
907 // /*public*/ long getSunRiseSet3(boolean rise) {
908 //
909 // // Compute day number for 0.0 Jan 2000 epoch
910 // double d = (double)(time - EPOCH_2000_MS) / DAY_MS;
911 //
912 // // Now compute the Local Sidereal Time, LST:
913 // //
914 // double LST = 98.9818 + 0.985647352 * d + /*UT*15 + long*/
915 // fLongitude*RAD_DEG;
916 // //
917 // // (east long. positive). Note that LST is here expressed in degrees,
918 // // where 15 degrees corresponds to one hour. Since LST really is an angle,
919 // // it's convenient to use one unit---degrees---throughout.
920 //
921 // // COMPUTING THE SUN'S POSITION
922 // // ----------------------------
923 // //
924 // // To be able to compute the Sun's rise/set times, you need to be able to
925 // // compute the Sun's position at any time. First compute the "day
926 // // number" d as outlined above, for the desired moment. Next compute:
927 // //
928 // double oblecl = 23.4393 - 3.563E-7 * d;
929 // //
930 // double w = 282.9404 + 4.70935E-5 * d;
931 // double M = 356.0470 + 0.9856002585 * d;
932 // double e = 0.016709 - 1.151E-9 * d;
933 // //
934 // // This is the obliquity of the ecliptic, plus some of the elements of
935 // // the Sun's apparent orbit (i.e., really the Earth's orbit): w =
936 // // argument of perihelion, M = mean anomaly, e = eccentricity.
937 // // Semi-major axis is here assumed to be exactly 1.0 (while not strictly
938 // // true, this is still an accurate approximation). Next compute E, the
939 // // eccentric anomaly:
940 // //
941 // double E = M + e*(180/PI) * ::sin(M*DEG_RAD) * ( 1.0 + e*cos(M*DEG_RAD) );
942 // //
943 // // where E and M are in degrees. This is it---no further iterations are
944 // // needed because we know e has a sufficiently small value. Next compute
945 // // the true anomaly, v, and the distance, r:
946 // //
947 // /* r * cos(v) = */ double A = cos(E*DEG_RAD) - e;
948 // /* r * ::sin(v) = */ double B = ::sqrt(1 - e*e) * ::sin(E*DEG_RAD);
949 // //
950 // // and
951 // //
952 // // r = sqrt( A*A + B*B )
953 // double v = ::atan2( B, A )*RAD_DEG;
954 // //
955 // // The Sun's true longitude, slon, can now be computed:
956 // //
957 // double slon = v + w;
958 // //
959 // // Since the Sun is always at the ecliptic (or at least very very close to
960 // // it), we can use simplified formulae to convert slon (the Sun's ecliptic
961 // // longitude) to sRA and sDec (the Sun's RA and Dec):
962 // //
963 // // ::sin(slon) * cos(oblecl)
964 // // tan(sRA) = -------------------------
965 // // cos(slon)
966 // //
967 // // ::sin(sDec) = ::sin(oblecl) * ::sin(slon)
968 // //
969 // // As was the case when computing az, the Azimuth, if possible use an
970 // // atan2() function to compute sRA.
971 //
972 // double sRA = ::atan2(sin(slon*DEG_RAD) * cos(oblecl*DEG_RAD), cos(slon*DEG_RAD))*RAD_DEG;
973 //
974 // double sin_sDec = ::sin(oblecl*DEG_RAD) * ::sin(slon*DEG_RAD);
975 // double sDec = ::asin(sin_sDec)*RAD_DEG;
976 //
977 // // COMPUTING RISE AND SET TIMES
978 // // ----------------------------
979 // //
980 // // To compute when an object rises or sets, you must compute when it
981 // // passes the meridian and the HA of rise/set. Then the rise time is
982 // // the meridian time minus HA for rise/set, and the set time is the
983 // // meridian time plus the HA for rise/set.
984 // //
985 // // To find the meridian time, compute the Local Sidereal Time at 0h local
986 // // time (or 0h UT if you prefer to work in UT) as outlined above---name
987 // // that quantity LST0. The Meridian Time, MT, will now be:
988 // //
989 // // MT = RA - LST0
990 // double MT = normalize(sRA - LST, 360);
991 // //
992 // // where "RA" is the object's Right Ascension (in degrees!). If negative,
993 // // add 360 deg to MT. If the object is the Sun, leave the time as it is,
994 // // but if it's stellar, multiply MT by 365.2422/366.2422, to convert from
995 // // sidereal to solar time. Now, compute HA for rise/set, name that
996 // // quantity HA0:
997 // //
998 // // ::sin(h0) - ::sin(lat) * ::sin(Dec)
999 // // cos(HA0) = ---------------------------------
1000 // // cos(lat) * cos(Dec)
1001 // //
1002 // // where h0 is the altitude selected to represent rise/set. For a purely
1003 // // mathematical horizon, set h0 = 0 and simplify to:
1004 // //
1005 // // cos(HA0) = - tan(lat) * tan(Dec)
1006 // //
1007 // // If you want to account for refraction on the atmosphere, set h0 = -35/60
1008 // // degrees (-35 arc minutes), and if you want to compute the rise/set times
1009 // // for the Sun's upper limb, set h0 = -50/60 (-50 arc minutes).
1010 // //
1011 // double h0 = -50/60 * DEG_RAD;
1012 //
1013 // double HA0 = ::acos(
1014 // (sin(h0) - ::sin(fLatitude) * sin_sDec) /
1015 // (cos(fLatitude) * cos(sDec*DEG_RAD)))*RAD_DEG;
1016 //
1017 // // When HA0 has been computed, leave it as it is for the Sun but multiply
1018 // // by 365.2422/366.2422 for stellar objects, to convert from sidereal to
1019 // // solar time. Finally compute:
1020 // //
1021 // // Rise time = MT - HA0
1022 // // Set time = MT + HA0
1023 // //
1024 // // convert the times from degrees to hours by dividing by 15.
1025 // //
1026 // // If you'd like to check that your calculations are accurate or just
1027 // // need a quick result, check the USNO's Sun or Moon Rise/Set Table,
1028 // // <URL:http://aa.usno.navy.mil/AA/data/docs/RS_OneYear.html>.
1029 //
1030 // double result = MT + (rise ? -HA0 : HA0); // in degrees
1031 //
1032 // // Find UT midnight on this day
1033 // long midnight = DAY_MS * (time / DAY_MS);
1034 //
1035 // return midnight + (long) (result * 3600000 / 15);
1036 // }
1037
1038 //-------------------------------------------------------------------------
1039 // The Moon
1040 //-------------------------------------------------------------------------
1041
1042 #define moonL0 (318.351648 * CalendarAstronomer::PI/180 ) // Mean long. at epoch
1043 #define moonP0 ( 36.340410 * CalendarAstronomer::PI/180 ) // Mean long. of perigee
1044 #define moonN0 ( 318.510107 * CalendarAstronomer::PI/180 ) // Mean long. of node
1045 #define moonI ( 5.145366 * CalendarAstronomer::PI/180 ) // Inclination of orbit
1046 #define moonE ( 0.054900 ) // Eccentricity of orbit
1047
1048 // These aren't used right now
1049 #define moonA ( 3.84401e5 ) // semi-major axis (km)
1050 #define moonT0 ( 0.5181 * CalendarAstronomer::PI/180 ) // Angular size at distance A
1051 #define moonPi ( 0.9507 * CalendarAstronomer::PI/180 ) // Parallax at distance A
1052
1053 /**
1054 * The position of the moon at the time set on this
1055 * object, in equatorial coordinates.
1056 * @internal
1057 * @deprecated ICU 2.4. This class may be removed or modified.
1058 */
getMoonPosition()1059 const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition()
1060 {
1061 //
1062 // See page 142 of "Practial Astronomy with your Calculator",
1063 // by Peter Duffet-Smith, for details on the algorithm.
1064 //
1065 if (moonPositionSet == FALSE) {
1066 // Calculate the solar longitude. Has the side effect of
1067 // filling in "meanAnomalySun" as well.
1068 getSunLongitude();
1069
1070 //
1071 // Find the # of days since the epoch of our orbital parameters.
1072 // TODO: Convert the time of day portion into ephemeris time
1073 //
1074 double day = getJulianDay() - JD_EPOCH; // Days since epoch
1075
1076 // Calculate the mean longitude and anomaly of the moon, based on
1077 // a circular orbit. Similar to the corresponding solar calculation.
1078 double meanLongitude = norm2PI(13.1763966*PI/180*day + moonL0);
1079 meanAnomalyMoon = norm2PI(meanLongitude - 0.1114041*PI/180 * day - moonP0);
1080
1081 //
1082 // Calculate the following corrections:
1083 // Evection: the sun's gravity affects the moon's eccentricity
1084 // Annual Eqn: variation in the effect due to earth-sun distance
1085 // A3: correction factor (for ???)
1086 //
1087 double evection = 1.2739*PI/180 * ::sin(2 * (meanLongitude - sunLongitude)
1088 - meanAnomalyMoon);
1089 double annual = 0.1858*PI/180 * ::sin(meanAnomalySun);
1090 double a3 = 0.3700*PI/180 * ::sin(meanAnomalySun);
1091
1092 meanAnomalyMoon += evection - annual - a3;
1093
1094 //
1095 // More correction factors:
1096 // center equation of the center correction
1097 // a4 yet another error correction (???)
1098 //
1099 // TODO: Skip the equation of the center correction and solve Kepler's eqn?
1100 //
1101 double center = 6.2886*PI/180 * ::sin(meanAnomalyMoon);
1102 double a4 = 0.2140*PI/180 * ::sin(2 * meanAnomalyMoon);
1103
1104 // Now find the moon's corrected longitude
1105 moonLongitude = meanLongitude + evection + center - annual + a4;
1106
1107 //
1108 // And finally, find the variation, caused by the fact that the sun's
1109 // gravitational pull on the moon varies depending on which side of
1110 // the earth the moon is on
1111 //
1112 double variation = 0.6583*CalendarAstronomer::PI/180 * ::sin(2*(moonLongitude - sunLongitude));
1113
1114 moonLongitude += variation;
1115
1116 //
1117 // What we've calculated so far is the moon's longitude in the plane
1118 // of its own orbit. Now map to the ecliptic to get the latitude
1119 // and longitude. First we need to find the longitude of the ascending
1120 // node, the position on the ecliptic where it is crossed by the moon's
1121 // orbit as it crosses from the southern to the northern hemisphere.
1122 //
1123 double nodeLongitude = norm2PI(moonN0 - 0.0529539*PI/180 * day);
1124
1125 nodeLongitude -= 0.16*PI/180 * ::sin(meanAnomalySun);
1126
1127 double y = ::sin(moonLongitude - nodeLongitude);
1128 double x = cos(moonLongitude - nodeLongitude);
1129
1130 moonEclipLong = ::atan2(y*cos(moonI), x) + nodeLongitude;
1131 double moonEclipLat = ::asin(y * ::sin(moonI));
1132
1133 eclipticToEquatorial(moonPosition, moonEclipLong, moonEclipLat);
1134 moonPositionSet = TRUE;
1135 }
1136 return moonPosition;
1137 }
1138
1139 /**
1140 * The "age" of the moon at the time specified in this object.
1141 * This is really the angle between the
1142 * current ecliptic longitudes of the sun and the moon,
1143 * measured in radians.
1144 *
1145 * @see #getMoonPhase
1146 * @internal
1147 * @deprecated ICU 2.4. This class may be removed or modified.
1148 */
getMoonAge()1149 double CalendarAstronomer::getMoonAge() {
1150 // See page 147 of "Practial Astronomy with your Calculator",
1151 // by Peter Duffet-Smith, for details on the algorithm.
1152 //
1153 // Force the moon's position to be calculated. We're going to use
1154 // some the intermediate results cached during that calculation.
1155 //
1156 getMoonPosition();
1157
1158 return norm2PI(moonEclipLong - sunLongitude);
1159 }
1160
1161 /**
1162 * Calculate the phase of the moon at the time set in this object.
1163 * The returned phase is a <code>double</code> in the range
1164 * <code>0 <= phase < 1</code>, interpreted as follows:
1165 * <ul>
1166 * <li>0.00: New moon
1167 * <li>0.25: First quarter
1168 * <li>0.50: Full moon
1169 * <li>0.75: Last quarter
1170 * </ul>
1171 *
1172 * @see #getMoonAge
1173 * @internal
1174 * @deprecated ICU 2.4. This class may be removed or modified.
1175 */
getMoonPhase()1176 double CalendarAstronomer::getMoonPhase() {
1177 // See page 147 of "Practial Astronomy with your Calculator",
1178 // by Peter Duffet-Smith, for details on the algorithm.
1179 return 0.5 * (1 - cos(getMoonAge()));
1180 }
1181
1182 /**
1183 * Constant representing a new moon.
1184 * For use with {@link #getMoonTime getMoonTime}
1185 * @internal
1186 * @deprecated ICU 2.4. This class may be removed or modified.
1187 */
NEW_MOON()1188 const CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() {
1189 return CalendarAstronomer::MoonAge(0);
1190 }
1191
1192 /**
1193 * Constant representing the moon's first quarter.
1194 * For use with {@link #getMoonTime getMoonTime}
1195 * @internal
1196 * @deprecated ICU 2.4. This class may be removed or modified.
1197 */
1198 /*const CalendarAstronomer::MoonAge CalendarAstronomer::FIRST_QUARTER() {
1199 return CalendarAstronomer::MoonAge(CalendarAstronomer::PI/2);
1200 }*/
1201
1202 /**
1203 * Constant representing a full moon.
1204 * For use with {@link #getMoonTime getMoonTime}
1205 * @internal
1206 * @deprecated ICU 2.4. This class may be removed or modified.
1207 */
FULL_MOON()1208 const CalendarAstronomer::MoonAge CalendarAstronomer::FULL_MOON() {
1209 return CalendarAstronomer::MoonAge(CalendarAstronomer::PI);
1210 }
1211 /**
1212 * Constant representing the moon's last quarter.
1213 * For use with {@link #getMoonTime getMoonTime}
1214 * @internal
1215 * @deprecated ICU 2.4. This class may be removed or modified.
1216 */
1217
1218 class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc {
1219 public:
eval(CalendarAstronomer & a)1220 virtual double eval(CalendarAstronomer&a) { return a.getMoonAge(); }
1221 };
1222
1223 /*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() {
1224 return CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2);
1225 }*/
1226
1227 /**
1228 * Find the next or previous time at which the Moon's ecliptic
1229 * longitude will have the desired value.
1230 * <p>
1231 * @param desired The desired longitude.
1232 * @param next <tt>true</tt> if the next occurrance of the phase
1233 * is desired, <tt>false</tt> for the previous occurrance.
1234 * @internal
1235 * @deprecated ICU 2.4. This class may be removed or modified.
1236 */
getMoonTime(double desired,UBool next)1237 UDate CalendarAstronomer::getMoonTime(double desired, UBool next)
1238 {
1239 MoonTimeAngleFunc func;
1240 return timeOfAngle( func,
1241 desired,
1242 SYNODIC_MONTH,
1243 MINUTE_MS,
1244 next);
1245 }
1246
1247 /**
1248 * Find the next or previous time at which the moon will be in the
1249 * desired phase.
1250 * <p>
1251 * @param desired The desired phase of the moon.
1252 * @param next <tt>true</tt> if the next occurrance of the phase
1253 * is desired, <tt>false</tt> for the previous occurrance.
1254 * @internal
1255 * @deprecated ICU 2.4. This class may be removed or modified.
1256 */
getMoonTime(const CalendarAstronomer::MoonAge & desired,UBool next)1257 UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) {
1258 return getMoonTime(desired.value, next);
1259 }
1260
1261 class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc {
1262 public:
eval(CalendarAstronomer::Equatorial & result,CalendarAstronomer & a)1263 virtual void eval(CalendarAstronomer::Equatorial& result, CalendarAstronomer&a) { result = a.getMoonPosition(); }
1264 };
1265
1266 /**
1267 * Returns the time (GMT) of sunrise or sunset on the local date to which
1268 * this calendar is currently set.
1269 * @internal
1270 * @deprecated ICU 2.4. This class may be removed or modified.
1271 */
getMoonRiseSet(UBool rise)1272 UDate CalendarAstronomer::getMoonRiseSet(UBool rise)
1273 {
1274 MoonRiseSetCoordFunc func;
1275 return riseOrSet(func,
1276 rise,
1277 .533 * DEG_RAD, // Angular Diameter
1278 34 /60.0 * DEG_RAD, // Refraction correction
1279 MINUTE_MS); // Desired accuracy
1280 }
1281
1282 //-------------------------------------------------------------------------
1283 // Interpolation methods for finding the time at which a given event occurs
1284 //-------------------------------------------------------------------------
1285
timeOfAngle(AngleFunc & func,double desired,double periodDays,double epsilon,UBool next)1286 UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired,
1287 double periodDays, double epsilon, UBool next)
1288 {
1289 // Find the value of the function at the current time
1290 double lastAngle = func.eval(*this);
1291
1292 // Find out how far we are from the desired angle
1293 double deltaAngle = norm2PI(desired - lastAngle) ;
1294
1295 // Using the average period, estimate the next (or previous) time at
1296 // which the desired angle occurs.
1297 double deltaT = (deltaAngle + (next ? 0.0 : - CalendarAstronomer_PI2 )) * (periodDays*DAY_MS) / CalendarAstronomer_PI2;
1298
1299 double lastDeltaT = deltaT; // Liu
1300 UDate startTime = fTime; // Liu
1301
1302 setTime(fTime + uprv_ceil(deltaT));
1303
1304 // Now iterate until we get the error below epsilon. Throughout
1305 // this loop we use normPI to get values in the range -Pi to Pi,
1306 // since we're using them as correction factors rather than absolute angles.
1307 do {
1308 // Evaluate the function at the time we've estimated
1309 double angle = func.eval(*this);
1310
1311 // Find the # of milliseconds per radian at this point on the curve
1312 double factor = uprv_fabs(deltaT / normPI(angle-lastAngle));
1313
1314 // Correct the time estimate based on how far off the angle is
1315 deltaT = normPI(desired - angle) * factor;
1316
1317 // HACK:
1318 //
1319 // If abs(deltaT) begins to diverge we need to quit this loop.
1320 // This only appears to happen when attempting to locate, for
1321 // example, a new moon on the day of the new moon. E.g.:
1322 //
1323 // This result is correct:
1324 // newMoon(7508(Mon Jul 23 00:00:00 CST 1990,false))=
1325 // Sun Jul 22 10:57:41 CST 1990
1326 //
1327 // But attempting to make the same call a day earlier causes deltaT
1328 // to diverge:
1329 // CalendarAstronomer.timeOfAngle() diverging: 1.348508727575625E9 ->
1330 // 1.3649828540224032E9
1331 // newMoon(7507(Sun Jul 22 00:00:00 CST 1990,false))=
1332 // Sun Jul 08 13:56:15 CST 1990
1333 //
1334 // As a temporary solution, we catch this specific condition and
1335 // adjust our start time by one eighth period days (either forward
1336 // or backward) and try again.
1337 // Liu 11/9/00
1338 if (uprv_fabs(deltaT) > uprv_fabs(lastDeltaT)) {
1339 double delta = uprv_ceil (periodDays * DAY_MS / 8.0);
1340 setTime(startTime + (next ? delta : -delta));
1341 return timeOfAngle(func, desired, periodDays, epsilon, next);
1342 }
1343
1344 lastDeltaT = deltaT;
1345 lastAngle = angle;
1346
1347 setTime(fTime + uprv_ceil(deltaT));
1348 }
1349 while (uprv_fabs(deltaT) > epsilon);
1350
1351 return fTime;
1352 }
1353
riseOrSet(CoordFunc & func,UBool rise,double diameter,double refraction,double epsilon)1354 UDate CalendarAstronomer::riseOrSet(CoordFunc& func, UBool rise,
1355 double diameter, double refraction,
1356 double epsilon)
1357 {
1358 Equatorial pos;
1359 double tanL = ::tan(fLatitude);
1360 double deltaT = 0;
1361 int32_t count = 0;
1362
1363 //
1364 // Calculate the object's position at the current time, then use that
1365 // position to calculate the time of rising or setting. The position
1366 // will be different at that time, so iterate until the error is allowable.
1367 //
1368 U_DEBUG_ASTRO_MSG(("setup rise=%s, dia=%.3lf, ref=%.3lf, eps=%.3lf\n",
1369 rise?"T":"F", diameter, refraction, epsilon));
1370 do {
1371 // See "Practical Astronomy With Your Calculator, section 33.
1372 func.eval(pos, *this);
1373 double angle = ::acos(-tanL * ::tan(pos.declination));
1374 double lst = ((rise ? CalendarAstronomer_PI2-angle : angle) + pos.ascension ) * 24 / CalendarAstronomer_PI2;
1375
1376 // Convert from LST to Universal Time.
1377 UDate newTime = lstToUT( lst );
1378
1379 deltaT = newTime - fTime;
1380 setTime(newTime);
1381 U_DEBUG_ASTRO_MSG(("%d] dT=%.3lf, angle=%.3lf, lst=%.3lf, A=%.3lf/D=%.3lf\n",
1382 count, deltaT, angle, lst, pos.ascension, pos.declination));
1383 }
1384 while (++ count < 5 && uprv_fabs(deltaT) > epsilon);
1385
1386 // Calculate the correction due to refraction and the object's angular diameter
1387 double cosD = ::cos(pos.declination);
1388 double psi = ::acos(sin(fLatitude) / cosD);
1389 double x = diameter / 2 + refraction;
1390 double y = ::asin(sin(x) / ::sin(psi));
1391 long delta = (long)((240 * y * RAD_DEG / cosD)*SECOND_MS);
1392
1393 return fTime + (rise ? -delta : delta);
1394 }
1395 /**
1396 * Return the obliquity of the ecliptic (the angle between the ecliptic
1397 * and the earth's equator) at the current time. This varies due to
1398 * the precession of the earth's axis.
1399 *
1400 * @return the obliquity of the ecliptic relative to the equator,
1401 * measured in radians.
1402 */
eclipticObliquity()1403 double CalendarAstronomer::eclipticObliquity() {
1404 if (isINVALID(eclipObliquity)) {
1405 const double epoch = 2451545.0; // 2000 AD, January 1.5
1406
1407 double T = (getJulianDay() - epoch) / 36525;
1408
1409 eclipObliquity = 23.439292
1410 - 46.815/3600 * T
1411 - 0.0006/3600 * T*T
1412 + 0.00181/3600 * T*T*T;
1413
1414 eclipObliquity *= DEG_RAD;
1415 }
1416 return eclipObliquity;
1417 }
1418
1419
1420 //-------------------------------------------------------------------------
1421 // Private data
1422 //-------------------------------------------------------------------------
clearCache()1423 void CalendarAstronomer::clearCache() {
1424 const double INVALID = uprv_getNaN();
1425
1426 julianDay = INVALID;
1427 julianCentury = INVALID;
1428 sunLongitude = INVALID;
1429 meanAnomalySun = INVALID;
1430 moonLongitude = INVALID;
1431 moonEclipLong = INVALID;
1432 meanAnomalyMoon = INVALID;
1433 eclipObliquity = INVALID;
1434 siderealTime = INVALID;
1435 siderealT0 = INVALID;
1436 moonPositionSet = FALSE;
1437 }
1438
1439 //private static void out(String s) {
1440 // System.out.println(s);
1441 //}
1442
1443 //private static String deg(double rad) {
1444 // return Double.toString(rad * RAD_DEG);
1445 //}
1446
1447 //private static String hours(long ms) {
1448 // return Double.toString((double)ms / HOUR_MS) + " hours";
1449 //}
1450
1451 /**
1452 * @internal
1453 * @deprecated ICU 2.4. This class may be removed or modified.
1454 */
1455 /*UDate CalendarAstronomer::local(UDate localMillis) {
1456 // TODO - srl ?
1457 TimeZone *tz = TimeZone::createDefault();
1458 int32_t rawOffset;
1459 int32_t dstOffset;
1460 UErrorCode status = U_ZERO_ERROR;
1461 tz->getOffset(localMillis, TRUE, rawOffset, dstOffset, status);
1462 delete tz;
1463 return localMillis - rawOffset;
1464 }*/
1465
1466 // Debugging functions
toString() const1467 UnicodeString CalendarAstronomer::Ecliptic::toString() const
1468 {
1469 #ifdef U_DEBUG_ASTRO
1470 char tmp[800];
1471 sprintf(tmp, "[%.5f,%.5f]", longitude*RAD_DEG, latitude*RAD_DEG);
1472 return UnicodeString(tmp, "");
1473 #else
1474 return UnicodeString();
1475 #endif
1476 }
1477
toString() const1478 UnicodeString CalendarAstronomer::Equatorial::toString() const
1479 {
1480 #ifdef U_DEBUG_ASTRO
1481 char tmp[400];
1482 sprintf(tmp, "%f,%f",
1483 (ascension*RAD_DEG), (declination*RAD_DEG));
1484 return UnicodeString(tmp, "");
1485 #else
1486 return UnicodeString();
1487 #endif
1488 }
1489
toString() const1490 UnicodeString CalendarAstronomer::Horizon::toString() const
1491 {
1492 #ifdef U_DEBUG_ASTRO
1493 char tmp[800];
1494 sprintf(tmp, "[%.5f,%.5f]", altitude*RAD_DEG, azimuth*RAD_DEG);
1495 return UnicodeString(tmp, "");
1496 #else
1497 return UnicodeString();
1498 #endif
1499 }
1500
1501
1502 // static private String radToHms(double angle) {
1503 // int hrs = (int) (angle*RAD_HOUR);
1504 // int min = (int)((angle*RAD_HOUR - hrs) * 60);
1505 // int sec = (int)((angle*RAD_HOUR - hrs - min/60.0) * 3600);
1506
1507 // return Integer.toString(hrs) + "h" + min + "m" + sec + "s";
1508 // }
1509
1510 // static private String radToDms(double angle) {
1511 // int deg = (int) (angle*RAD_DEG);
1512 // int min = (int)((angle*RAD_DEG - deg) * 60);
1513 // int sec = (int)((angle*RAD_DEG - deg - min/60.0) * 3600);
1514
1515 // return Integer.toString(deg) + "\u00b0" + min + "'" + sec + "\"";
1516 // }
1517
1518 // =============== Calendar Cache ================
1519
createCache(CalendarCache ** cache,UErrorCode & status)1520 void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) {
1521 ucln_i18n_registerCleanup(UCLN_I18N_ASTRO_CALENDAR, calendar_astro_cleanup);
1522 if(cache == NULL) {
1523 status = U_MEMORY_ALLOCATION_ERROR;
1524 } else {
1525 *cache = new CalendarCache(32, status);
1526 if(U_FAILURE(status)) {
1527 delete *cache;
1528 *cache = NULL;
1529 }
1530 }
1531 }
1532
get(CalendarCache ** cache,int32_t key,UErrorCode & status)1533 int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) {
1534 int32_t res;
1535
1536 if(U_FAILURE(status)) {
1537 return 0;
1538 }
1539 umtx_lock(&ccLock);
1540
1541 if(*cache == NULL) {
1542 createCache(cache, status);
1543 if(U_FAILURE(status)) {
1544 umtx_unlock(&ccLock);
1545 return 0;
1546 }
1547 }
1548
1549 res = uhash_igeti((*cache)->fTable, key);
1550 U_DEBUG_ASTRO_MSG(("%p: GET: [%d] == %d\n", (*cache)->fTable, key, res));
1551
1552 umtx_unlock(&ccLock);
1553 return res;
1554 }
1555
put(CalendarCache ** cache,int32_t key,int32_t value,UErrorCode & status)1556 void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) {
1557 if(U_FAILURE(status)) {
1558 return;
1559 }
1560 umtx_lock(&ccLock);
1561
1562 if(*cache == NULL) {
1563 createCache(cache, status);
1564 if(U_FAILURE(status)) {
1565 umtx_unlock(&ccLock);
1566 return;
1567 }
1568 }
1569
1570 uhash_iputi((*cache)->fTable, key, value, &status);
1571 U_DEBUG_ASTRO_MSG(("%p: PUT: [%d] := %d\n", (*cache)->fTable, key, value));
1572
1573 umtx_unlock(&ccLock);
1574 }
1575
CalendarCache(int32_t size,UErrorCode & status)1576 CalendarCache::CalendarCache(int32_t size, UErrorCode &status) {
1577 fTable = uhash_openSize(uhash_hashLong, uhash_compareLong, NULL, size, &status);
1578 U_DEBUG_ASTRO_MSG(("%p: Opening.\n", fTable));
1579 }
1580
~CalendarCache()1581 CalendarCache::~CalendarCache() {
1582 if(fTable != NULL) {
1583 U_DEBUG_ASTRO_MSG(("%p: Closing.\n", fTable));
1584 uhash_close(fTable);
1585 }
1586 }
1587
1588 U_NAMESPACE_END
1589
1590 #endif // !UCONFIG_NO_FORMATTING
1591