// © 2016 and later: Unicode, Inc. and others. // License & terms of use: http://www.unicode.org/copyright.html /************************************************************************ * Copyright (C) 1996-2012, International Business Machines Corporation * and others. All Rights Reserved. ************************************************************************ * 2003-nov-07 srl Port from Java */ #include "astro.h" #if !UCONFIG_NO_FORMATTING #include "unicode/calendar.h" #include <math.h> #include <float.h> #include "unicode/putil.h" #include "uhash.h" #include "umutex.h" #include "ucln_in.h" #include "putilimp.h" #include <stdio.h> // for toString() #if defined (PI) #undef PI #endif #ifdef U_DEBUG_ASTRO # include "uresimp.h" // for debugging static void debug_astro_loc(const char *f, int32_t l) { fprintf(stderr, "%s:%d: ", f, l); } static void debug_astro_msg(const char *pat, ...) { va_list ap; va_start(ap, pat); vfprintf(stderr, pat, ap); fflush(stderr); } #include "unicode/datefmt.h" #include "unicode/ustring.h" static const char * debug_astro_date(UDate d) { static char gStrBuf[1024]; static DateFormat *df = nullptr; if(df == nullptr) { df = DateFormat::createDateTimeInstance(DateFormat::MEDIUM, DateFormat::MEDIUM, Locale::getUS()); df->adoptTimeZone(TimeZone::getGMT()->clone()); } UnicodeString str; df->format(d,str); u_austrncpy(gStrBuf,str.getTerminatedBuffer(),sizeof(gStrBuf)-1); return gStrBuf; } // must use double parens, i.e.: U_DEBUG_ASTRO_MSG(("four is: %d",4)); #define U_DEBUG_ASTRO_MSG … #else #define U_DEBUG_ASTRO_MSG(x) … #endif static inline UBool isINVALID(double d) { … } static icu::UMutex ccLock; U_CDECL_BEGIN static UBool calendar_astro_cleanup() { … } U_CDECL_END U_NAMESPACE_BEGIN /** * The number of standard hours in one sidereal day. * Approximately 24.93. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define SIDEREAL_DAY … /** * The number of sidereal hours in one mean solar day. * Approximately 24.07. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define SOLAR_DAY … /** * The average number of solar days from one new moon to the next. This is the time * it takes for the moon to return the same ecliptic longitude as the sun. * It is longer than the sidereal month because the sun's longitude increases * during the year due to the revolution of the earth around the sun. * Approximately 29.53. * * @see #SIDEREAL_MONTH * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ const double CalendarAstronomer::SYNODIC_MONTH = …; /** * The average number of days it takes * for the moon to return to the same ecliptic longitude relative to the * stellar background. This is referred to as the sidereal month. * It is shorter than the synodic month due to * the revolution of the earth around the sun. * Approximately 27.32. * * @see #SYNODIC_MONTH * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define SIDEREAL_MONTH … /** * The average number number of days between successive vernal equinoxes. * Due to the precession of the earth's * axis, this is not precisely the same as the sidereal year. * Approximately 365.24 * * @see #SIDEREAL_YEAR * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define TROPICAL_YEAR … /** * The average number of days it takes * for the sun to return to the same position against the fixed stellar * background. This is the duration of one orbit of the earth about the sun * as it would appear to an outside observer. * Due to the precession of the earth's * axis, this is not precisely the same as the tropical year. * Approximately 365.25. * * @see #TROPICAL_YEAR * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define SIDEREAL_YEAR … //------------------------------------------------------------------------- // Time-related constants //------------------------------------------------------------------------- /** * The number of milliseconds in one second. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define SECOND_MS … /** * The number of milliseconds in one minute. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define MINUTE_MS … /** * The number of milliseconds in one hour. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define HOUR_MS … /** * The number of milliseconds in one day. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define DAY_MS … /** * The start of the julian day numbering scheme used by astronomers, which * is 1/1/4713 BC (Julian), 12:00 GMT. This is given as the number of milliseconds * since 1/1/1970 AD (Gregorian), a negative number. * Note that julian day numbers and * the Julian calendar are <em>not</em> the same thing. Also note that * julian days start at <em>noon</em>, not midnight. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ #define JULIAN_EPOCH_MS … /** * Milliseconds value for 0.0 January 2000 AD. */ #define EPOCH_2000_MS … //------------------------------------------------------------------------- // Assorted private data used for conversions //------------------------------------------------------------------------- // My own copies of these so compilers are more likely to optimize them away const double CalendarAstronomer::PI = …; #define CalendarAstronomer_PI2 … #define RAD_HOUR … #define DEG_RAD … #define RAD_DEG … /*** * Given 'value', add or subtract 'range' until 0 <= 'value' < range. * The modulus operator. */ inline static double normalize(double value, double range) { … } /** * Normalize an angle so that it's in the range 0 - 2pi. * For positive angles this is just (angle % 2pi), but the Java * mod operator doesn't work that way for negative numbers.... */ inline static double norm2PI(double angle) { … } /** * Normalize an angle into the range -PI - PI */ inline static double normPI(double angle) { … } //------------------------------------------------------------------------- // Constructors //------------------------------------------------------------------------- /** * Construct a new <code>CalendarAstronomer</code> object that is initialized to * the current date and time. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::CalendarAstronomer(): … { … } /** * Construct a new <code>CalendarAstronomer</code> object that is initialized to * the specified date and time. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::CalendarAstronomer(UDate d): … { … } /** * Construct a new <code>CalendarAstronomer</code> object with the given * latitude and longitude. The object's time is set to the current * date and time. * <p> * @param longitude The desired longitude, in <em>degrees</em> east of * the Greenwich meridian. * * @param latitude The desired latitude, in <em>degrees</em>. Positive * values signify North, negative South. * * @see java.util.Date#getTime() * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::CalendarAstronomer(double longitude, double latitude) : … { … } CalendarAstronomer::~CalendarAstronomer() { … } //------------------------------------------------------------------------- // Time and date getters and setters //------------------------------------------------------------------------- /** * Set the current date and time of this <code>CalendarAstronomer</code> object. All * astronomical calculations are performed based on this time setting. * * @param aTime the date and time, expressed as the number of milliseconds since * 1/1/1970 0:00 GMT (Gregorian). * * @see #setDate * @see #getTime * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ void CalendarAstronomer::setTime(UDate aTime) { … } /** * Set the current date and time of this <code>CalendarAstronomer</code> object. All * astronomical calculations are performed based on this time setting. * * @param jdn the desired time, expressed as a "julian day number", * which is the number of elapsed days since * 1/1/4713 BC (Julian), 12:00 GMT. Note that julian day * numbers start at <em>noon</em>. To get the jdn for * the corresponding midnight, subtract 0.5. * * @see #getJulianDay * @see #JULIAN_EPOCH_MS * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ void CalendarAstronomer::setJulianDay(double jdn) { … } /** * Get the current time of this <code>CalendarAstronomer</code> object, * represented as the number of milliseconds since * 1/1/1970 AD 0:00 GMT (Gregorian). * * @see #setTime * @see #getDate * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ UDate CalendarAstronomer::getTime() { … } /** * Get the current time of this <code>CalendarAstronomer</code> object, * expressed as a "julian day number", which is the number of elapsed * days since 1/1/4713 BC (Julian), 12:00 GMT. * * @see #setJulianDay * @see #JULIAN_EPOCH_MS * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::getJulianDay() { … } /** * Return this object's time expressed in julian centuries: * the number of centuries after 1/1/1900 AD, 12:00 GMT * * @see #getJulianDay * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::getJulianCentury() { … } /** * Returns the current Greenwich sidereal time, measured in hours * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::getGreenwichSidereal() { … } double CalendarAstronomer::getSiderealOffset() { … } /** * Returns the current local sidereal time, measured in hours * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::getLocalSidereal() { … } /** * Converts local sidereal time to Universal Time. * * @param lst The Local Sidereal Time, in hours since sidereal midnight * on this object's current date. * * @return The corresponding Universal Time, in milliseconds since * 1 Jan 1970, GMT. */ double CalendarAstronomer::lstToUT(double lst) { … } //------------------------------------------------------------------------- // Coordinate transformations, all based on the current time of this object //------------------------------------------------------------------------- /** * Convert from ecliptic to equatorial coordinates. * * @param ecliptic A point in the sky in ecliptic coordinates. * @return The corresponding point in equatorial coordinates. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, const CalendarAstronomer::Ecliptic& ecliptic) { … } /** * Convert from ecliptic to equatorial coordinates. * * @param eclipLong The ecliptic longitude * @param eclipLat The ecliptic latitude * * @return The corresponding point in equatorial coordinates. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong, double eclipLat) { … } /** * Convert from ecliptic longitude to equatorial coordinates. * * @param eclipLong The ecliptic longitude * * @return The corresponding point in equatorial coordinates. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::Equatorial& CalendarAstronomer::eclipticToEquatorial(CalendarAstronomer::Equatorial& result, double eclipLong) { … } /** * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::Horizon& CalendarAstronomer::eclipticToHorizon(CalendarAstronomer::Horizon& result, double eclipLong) { … } //------------------------------------------------------------------------- // The Sun //------------------------------------------------------------------------- // // Parameters of the Sun's orbit as of the epoch Jan 0.0 1990 // Angles are in radians (after multiplying by CalendarAstronomer::PI/180) // #define JD_EPOCH … #define SUN_ETA_G … #define SUN_OMEGA_G … #define SUN_E … //double sunR0 1.495585e8 // Semi-major axis in KM //double sunTheta0 (0.533128 * CalendarAstronomer::PI/180) // Angular diameter at R0 // The following three methods, which compute the sun parameters // given above for an arbitrary epoch (whatever time the object is // set to), make only a small difference as compared to using the // above constants. E.g., Sunset times might differ by ~12 // seconds. Furthermore, the eta-g computation is befuddled by // Duffet-Smith's incorrect coefficients (p.86). I've corrected // the first-order coefficient but the others may be off too - no // way of knowing without consulting another source. // /** // * Return the sun's ecliptic longitude at perigee for the current time. // * See Duffett-Smith, p. 86. // * @return radians // */ // private double getSunOmegaG() { // double T = getJulianCentury(); // return (281.2208444 + (1.719175 + 0.000452778*T)*T) * DEG_RAD; // } // /** // * Return the sun's ecliptic longitude for the current time. // * See Duffett-Smith, p. 86. // * @return radians // */ // private double getSunEtaG() { // double T = getJulianCentury(); // //return (279.6966778 + (36000.76892 + 0.0003025*T)*T) * DEG_RAD; // // // // The above line is from Duffett-Smith, and yields manifestly wrong // // results. The below constant is derived empirically to match the // // constant he gives for the 1990 EPOCH. // // // return (279.6966778 + (-0.3262541582718024 + 0.0003025*T)*T) * DEG_RAD; // } // /** // * Return the sun's eccentricity of orbit for the current time. // * See Duffett-Smith, p. 86. // * @return double // */ // private double getSunE() { // double T = getJulianCentury(); // return 0.01675104 - (0.0000418 + 0.000000126*T)*T; // } /** * Find the "true anomaly" (longitude) of an object from * its mean anomaly and the eccentricity of its orbit. This uses * an iterative solution to Kepler's equation. * * @param meanAnomaly The object's longitude calculated as if it were in * a regular, circular orbit, measured in radians * from the point of perigee. * * @param eccentricity The eccentricity of the orbit * * @return The true anomaly (longitude) measured in radians */ static double trueAnomaly(double meanAnomaly, double eccentricity) { … } /** * The longitude of the sun at the time specified by this object. * The longitude is measured in radians along the ecliptic * from the "first point of Aries," the point at which the ecliptic * crosses the earth's equatorial plane at the vernal equinox. * <p> * Currently, this method uses an approximation of the two-body Kepler's * equation for the earth and the sun. It does not take into account the * perturbations caused by the other planets, the moon, etc. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::getSunLongitude() { … } /** * TODO Make this public when the entire class is package-private. */ /*public*/ void CalendarAstronomer::getSunLongitude(double jDay, double &longitude, double &meanAnomaly) { … } /** * The position of the sun at this object's current date and time, * in equatorial coordinates. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ CalendarAstronomer::Equatorial& CalendarAstronomer::getSunPosition(CalendarAstronomer::Equatorial& result) { … } /** * Constant representing the vernal equinox. * For use with {@link #getSunTime getSunTime}. * Note: In this case, "vernal" refers to the northern hemisphere's seasons. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ /*double CalendarAstronomer::VERNAL_EQUINOX() { return 0; }*/ /** * Constant representing the summer solstice. * For use with {@link #getSunTime getSunTime}. * Note: In this case, "summer" refers to the northern hemisphere's seasons. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::SUMMER_SOLSTICE() { … } /** * Constant representing the autumnal equinox. * For use with {@link #getSunTime getSunTime}. * Note: In this case, "autumn" refers to the northern hemisphere's seasons. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ /*double CalendarAstronomer::AUTUMN_EQUINOX() { return (CalendarAstronomer::PI); }*/ /** * Constant representing the winter solstice. * For use with {@link #getSunTime getSunTime}. * Note: In this case, "winter" refers to the northern hemisphere's seasons. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::WINTER_SOLSTICE() { … } CalendarAstronomer::AngleFunc::~AngleFunc() { … } /** * Find the next time at which the sun's ecliptic longitude will have * the desired value. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ class SunTimeAngleFunc : public CalendarAstronomer::AngleFunc { … }; SunTimeAngleFunc::~SunTimeAngleFunc() { … } UDate CalendarAstronomer::getSunTime(double desired, UBool next) { … } CalendarAstronomer::CoordFunc::~CoordFunc() { … } class RiseSetCoordFunc : public CalendarAstronomer::CoordFunc { … }; RiseSetCoordFunc::~RiseSetCoordFunc() { … } UDate CalendarAstronomer::getSunRiseSet(UBool rise) { … } // Commented out - currently unused. ICU 2.6, Alan // //------------------------------------------------------------------------- // // Alternate Sun Rise/Set // // See Duffett-Smith p.93 // //------------------------------------------------------------------------- // // // This yields worse results (as compared to USNO data) than getSunRiseSet(). // /** // * TODO Make this when the entire class is package-private. // */ // /*public*/ long getSunRiseSet2(boolean rise) { // // 1. Calculate coordinates of the sun's center for midnight // double jd = uprv_floor(getJulianDay() - 0.5) + 0.5; // double[] sl = getSunLongitude(jd);// double lambda1 = sl[0]; // Equatorial pos1 = eclipticToEquatorial(lambda1, 0); // // // 2. Add ... to lambda to get position 24 hours later // double lambda2 = lambda1 + 0.985647*DEG_RAD; // Equatorial pos2 = eclipticToEquatorial(lambda2, 0); // // // 3. Calculate LSTs of rising and setting for these two positions // double tanL = ::tan(fLatitude); // double H = ::acos(-tanL * ::tan(pos1.declination)); // double lst1r = (CalendarAstronomer_PI2 + pos1.ascension - H) * 24 / CalendarAstronomer_PI2; // double lst1s = (pos1.ascension + H) * 24 / CalendarAstronomer_PI2; // H = ::acos(-tanL * ::tan(pos2.declination)); // double lst2r = (CalendarAstronomer_PI2-H + pos2.ascension ) * 24 / CalendarAstronomer_PI2; // double lst2s = (H + pos2.ascension ) * 24 / CalendarAstronomer_PI2; // if (lst1r > 24) lst1r -= 24; // if (lst1s > 24) lst1s -= 24; // if (lst2r > 24) lst2r -= 24; // if (lst2s > 24) lst2s -= 24; // // // 4. Convert LSTs to GSTs. If GST1 > GST2, add 24 to GST2. // double gst1r = lstToGst(lst1r); // double gst1s = lstToGst(lst1s); // double gst2r = lstToGst(lst2r); // double gst2s = lstToGst(lst2s); // if (gst1r > gst2r) gst2r += 24; // if (gst1s > gst2s) gst2s += 24; // // // 5. Calculate GST at 0h UT of this date // double t00 = utToGst(0); // // // 6. Calculate GST at 0h on the observer's longitude // double offset = ::round(fLongitude*12/PI); // p.95 step 6; he _rounds_ to nearest 15 deg. // double t00p = t00 - offset*1.002737909; // if (t00p < 0) t00p += 24; // do NOT normalize // // // 7. Adjust // if (gst1r < t00p) { // gst1r += 24; // gst2r += 24; // } // if (gst1s < t00p) { // gst1s += 24; // gst2s += 24; // } // // // 8. // double gstr = (24.07*gst1r-t00*(gst2r-gst1r))/(24.07+gst1r-gst2r); // double gsts = (24.07*gst1s-t00*(gst2s-gst1s))/(24.07+gst1s-gst2s); // // // 9. Correct for parallax, refraction, and sun's diameter // double dec = (pos1.declination + pos2.declination) / 2; // double psi = ::acos(sin(fLatitude) / cos(dec)); // double x = 0.830725 * DEG_RAD; // parallax+refraction+diameter // double y = ::asin(sin(x) / ::sin(psi)) * RAD_DEG; // double delta_t = 240 * y / cos(dec) / 3600; // hours // // // 10. Add correction to GSTs, subtract from GSTr // gstr -= delta_t; // gsts += delta_t; // // // 11. Convert GST to UT and then to local civil time // double ut = gstToUt(rise ? gstr : gsts); // //System.out.println((rise?"rise=":"set=") + ut + ", delta_t=" + delta_t); // long midnight = DAY_MS * (time / DAY_MS); // Find UT midnight on this day // return midnight + (long) (ut * 3600000); // } // Commented out - currently unused. ICU 2.6, Alan // /** // * Convert local sidereal time to Greenwich sidereal time. // * Section 15. Duffett-Smith p.21 // * @param lst in hours (0..24) // * @return GST in hours (0..24) // */ // double lstToGst(double lst) { // double delta = fLongitude * 24 / CalendarAstronomer_PI2; // return normalize(lst - delta, 24); // } // Commented out - currently unused. ICU 2.6, Alan // /** // * Convert UT to GST on this date. // * Section 12. Duffett-Smith p.17 // * @param ut in hours // * @return GST in hours // */ // double utToGst(double ut) { // return normalize(getT0() + ut*1.002737909, 24); // } // Commented out - currently unused. ICU 2.6, Alan // /** // * Convert GST to UT on this date. // * Section 13. Duffett-Smith p.18 // * @param gst in hours // * @return UT in hours // */ // double gstToUt(double gst) { // return normalize(gst - getT0(), 24) * 0.9972695663; // } // Commented out - currently unused. ICU 2.6, Alan // double getT0() { // // Common computation for UT <=> GST // // // Find JD for 0h UT // double jd = uprv_floor(getJulianDay() - 0.5) + 0.5; // // double s = jd - 2451545.0; // double t = s / 36525.0; // double t0 = 6.697374558 + (2400.051336 + 0.000025862*t)*t; // return t0; // } // Commented out - currently unused. ICU 2.6, Alan // //------------------------------------------------------------------------- // // Alternate Sun Rise/Set // // See sci.astro FAQ // // http://www.faqs.org/faqs/astronomy/faq/part3/section-5.html // //------------------------------------------------------------------------- // // // Note: This method appears to produce inferior accuracy as // // compared to getSunRiseSet(). // // /** // * TODO Make this when the entire class is package-private. // */ // /*public*/ long getSunRiseSet3(boolean rise) { // // // Compute day number for 0.0 Jan 2000 epoch // double d = (double)(time - EPOCH_2000_MS) / DAY_MS; // // // Now compute the Local Sidereal Time, LST: // // // double LST = 98.9818 + 0.985647352 * d + /*UT*15 + long*/ // fLongitude*RAD_DEG; // // // // (east long. positive). Note that LST is here expressed in degrees, // // where 15 degrees corresponds to one hour. Since LST really is an angle, // // it's convenient to use one unit---degrees---throughout. // // // COMPUTING THE SUN'S POSITION // // ---------------------------- // // // // To be able to compute the Sun's rise/set times, you need to be able to // // compute the Sun's position at any time. First compute the "day // // number" d as outlined above, for the desired moment. Next compute: // // // double oblecl = 23.4393 - 3.563E-7 * d; // // // double w = 282.9404 + 4.70935E-5 * d; // double M = 356.0470 + 0.9856002585 * d; // double e = 0.016709 - 1.151E-9 * d; // // // // This is the obliquity of the ecliptic, plus some of the elements of // // the Sun's apparent orbit (i.e., really the Earth's orbit): w = // // argument of perihelion, M = mean anomaly, e = eccentricity. // // Semi-major axis is here assumed to be exactly 1.0 (while not strictly // // true, this is still an accurate approximation). Next compute E, the // // eccentric anomaly: // // // double E = M + e*(180/PI) * ::sin(M*DEG_RAD) * ( 1.0 + e*cos(M*DEG_RAD) ); // // // // where E and M are in degrees. This is it---no further iterations are // // needed because we know e has a sufficiently small value. Next compute // // the true anomaly, v, and the distance, r: // // // /* r * cos(v) = */ double A = cos(E*DEG_RAD) - e; // /* r * ::sin(v) = */ double B = ::sqrt(1 - e*e) * ::sin(E*DEG_RAD); // // // // and // // // // r = sqrt( A*A + B*B ) // double v = ::atan2( B, A )*RAD_DEG; // // // // The Sun's true longitude, slon, can now be computed: // // // double slon = v + w; // // // // Since the Sun is always at the ecliptic (or at least very very close to // // it), we can use simplified formulae to convert slon (the Sun's ecliptic // // longitude) to sRA and sDec (the Sun's RA and Dec): // // // // ::sin(slon) * cos(oblecl) // // tan(sRA) = ------------------------- // // cos(slon) // // // // ::sin(sDec) = ::sin(oblecl) * ::sin(slon) // // // // As was the case when computing az, the Azimuth, if possible use an // // atan2() function to compute sRA. // // double sRA = ::atan2(sin(slon*DEG_RAD) * cos(oblecl*DEG_RAD), cos(slon*DEG_RAD))*RAD_DEG; // // double sin_sDec = ::sin(oblecl*DEG_RAD) * ::sin(slon*DEG_RAD); // double sDec = ::asin(sin_sDec)*RAD_DEG; // // // COMPUTING RISE AND SET TIMES // // ---------------------------- // // // // To compute when an object rises or sets, you must compute when it // // passes the meridian and the HA of rise/set. Then the rise time is // // the meridian time minus HA for rise/set, and the set time is the // // meridian time plus the HA for rise/set. // // // // To find the meridian time, compute the Local Sidereal Time at 0h local // // time (or 0h UT if you prefer to work in UT) as outlined above---name // // that quantity LST0. The Meridian Time, MT, will now be: // // // // MT = RA - LST0 // double MT = normalize(sRA - LST, 360); // // // // where "RA" is the object's Right Ascension (in degrees!). If negative, // // add 360 deg to MT. If the object is the Sun, leave the time as it is, // // but if it's stellar, multiply MT by 365.2422/366.2422, to convert from // // sidereal to solar time. Now, compute HA for rise/set, name that // // quantity HA0: // // // // ::sin(h0) - ::sin(lat) * ::sin(Dec) // // cos(HA0) = --------------------------------- // // cos(lat) * cos(Dec) // // // // where h0 is the altitude selected to represent rise/set. For a purely // // mathematical horizon, set h0 = 0 and simplify to: // // // // cos(HA0) = - tan(lat) * tan(Dec) // // // // If you want to account for refraction on the atmosphere, set h0 = -35/60 // // degrees (-35 arc minutes), and if you want to compute the rise/set times // // for the Sun's upper limb, set h0 = -50/60 (-50 arc minutes). // // // double h0 = -50/60 * DEG_RAD; // // double HA0 = ::acos( // (sin(h0) - ::sin(fLatitude) * sin_sDec) / // (cos(fLatitude) * cos(sDec*DEG_RAD)))*RAD_DEG; // // // When HA0 has been computed, leave it as it is for the Sun but multiply // // by 365.2422/366.2422 for stellar objects, to convert from sidereal to // // solar time. Finally compute: // // // // Rise time = MT - HA0 // // Set time = MT + HA0 // // // // convert the times from degrees to hours by dividing by 15. // // // // If you'd like to check that your calculations are accurate or just // // need a quick result, check the USNO's Sun or Moon Rise/Set Table, // // <URL:http://aa.usno.navy.mil/AA/data/docs/RS_OneYear.html>. // // double result = MT + (rise ? -HA0 : HA0); // in degrees // // // Find UT midnight on this day // long midnight = DAY_MS * (time / DAY_MS); // // return midnight + (long) (result * 3600000 / 15); // } //------------------------------------------------------------------------- // The Moon //------------------------------------------------------------------------- #define moonL0 … #define moonP0 … #define moonN0 … #define moonI … #define moonE … // These aren't used right now #define moonA … #define moonT0 … #define moonPi … /** * The position of the moon at the time set on this * object, in equatorial coordinates. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ const CalendarAstronomer::Equatorial& CalendarAstronomer::getMoonPosition() { … } /** * The "age" of the moon at the time specified in this object. * This is really the angle between the * current ecliptic longitudes of the sun and the moon, * measured in radians. * * @see #getMoonPhase * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::getMoonAge() { … } /** * Calculate the phase of the moon at the time set in this object. * The returned phase is a <code>double</code> in the range * <code>0 <= phase < 1</code>, interpreted as follows: * <ul> * <li>0.00: New moon * <li>0.25: First quarter * <li>0.50: Full moon * <li>0.75: Last quarter * </ul> * * @see #getMoonAge * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ double CalendarAstronomer::getMoonPhase() { … } /** * Constant representing a new moon. * For use with {@link #getMoonTime getMoonTime} * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ const CalendarAstronomer::MoonAge CalendarAstronomer::NEW_MOON() { … } /** * Constant representing the moon's first quarter. * For use with {@link #getMoonTime getMoonTime} * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ /*const CalendarAstronomer::MoonAge CalendarAstronomer::FIRST_QUARTER() { return CalendarAstronomer::MoonAge(CalendarAstronomer::PI/2); }*/ /** * Constant representing a full moon. * For use with {@link #getMoonTime getMoonTime} * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ const CalendarAstronomer::MoonAge CalendarAstronomer::FULL_MOON() { … } /** * Constant representing the moon's last quarter. * For use with {@link #getMoonTime getMoonTime} * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ class MoonTimeAngleFunc : public CalendarAstronomer::AngleFunc { … }; MoonTimeAngleFunc::~MoonTimeAngleFunc() { … } /*const CalendarAstronomer::MoonAge CalendarAstronomer::LAST_QUARTER() { return CalendarAstronomer::MoonAge((CalendarAstronomer::PI*3)/2); }*/ /** * Find the next or previous time at which the Moon's ecliptic * longitude will have the desired value. * <p> * @param desired The desired longitude. * @param next <tt>true</tt> if the next occurrence of the phase * is desired, <tt>false</tt> for the previous occurrence. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ UDate CalendarAstronomer::getMoonTime(double desired, UBool next) { … } /** * Find the next or previous time at which the moon will be in the * desired phase. * <p> * @param desired The desired phase of the moon. * @param next <tt>true</tt> if the next occurrence of the phase * is desired, <tt>false</tt> for the previous occurrence. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ UDate CalendarAstronomer::getMoonTime(const CalendarAstronomer::MoonAge& desired, UBool next) { … } class MoonRiseSetCoordFunc : public CalendarAstronomer::CoordFunc { … }; MoonRiseSetCoordFunc::~MoonRiseSetCoordFunc() { … } /** * Returns the time (GMT) of sunrise or sunset on the local date to which * this calendar is currently set. * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ UDate CalendarAstronomer::getMoonRiseSet(UBool rise) { … } //------------------------------------------------------------------------- // Interpolation methods for finding the time at which a given event occurs //------------------------------------------------------------------------- UDate CalendarAstronomer::timeOfAngle(AngleFunc& func, double desired, double periodDays, double epsilon, UBool next) { … } UDate CalendarAstronomer::riseOrSet(CoordFunc& func, UBool rise, double diameter, double refraction, double epsilon) { … } /** * Return the obliquity of the ecliptic (the angle between the ecliptic * and the earth's equator) at the current time. This varies due to * the precession of the earth's axis. * * @return the obliquity of the ecliptic relative to the equator, * measured in radians. */ double CalendarAstronomer::eclipticObliquity() { … } //------------------------------------------------------------------------- // Private data //------------------------------------------------------------------------- void CalendarAstronomer::clearCache() { … } //private static void out(String s) { // System.out.println(s); //} //private static String deg(double rad) { // return Double.toString(rad * RAD_DEG); //} //private static String hours(long ms) { // return Double.toString((double)ms / HOUR_MS) + " hours"; //} /** * @internal * @deprecated ICU 2.4. This class may be removed or modified. */ /*UDate CalendarAstronomer::local(UDate localMillis) { // TODO - srl ? TimeZone *tz = TimeZone::createDefault(); int32_t rawOffset; int32_t dstOffset; UErrorCode status = U_ZERO_ERROR; tz->getOffset(localMillis, true, rawOffset, dstOffset, status); delete tz; return localMillis - rawOffset; }*/ // Debugging functions UnicodeString CalendarAstronomer::Ecliptic::toString() const { … } UnicodeString CalendarAstronomer::Equatorial::toString() const { … } UnicodeString CalendarAstronomer::Horizon::toString() const { … } // static private String radToHms(double angle) { // int hrs = (int) (angle*RAD_HOUR); // int min = (int)((angle*RAD_HOUR - hrs) * 60); // int sec = (int)((angle*RAD_HOUR - hrs - min/60.0) * 3600); // return Integer.toString(hrs) + "h" + min + "m" + sec + "s"; // } // static private String radToDms(double angle) { // int deg = (int) (angle*RAD_DEG); // int min = (int)((angle*RAD_DEG - deg) * 60); // int sec = (int)((angle*RAD_DEG - deg - min/60.0) * 3600); // return Integer.toString(deg) + "\u00b0" + min + "'" + sec + "\""; // } // =============== Calendar Cache ================ void CalendarCache::createCache(CalendarCache** cache, UErrorCode& status) { … } int32_t CalendarCache::get(CalendarCache** cache, int32_t key, UErrorCode &status) { … } void CalendarCache::put(CalendarCache** cache, int32_t key, int32_t value, UErrorCode &status) { … } CalendarCache::CalendarCache(int32_t size, UErrorCode &status) { … } CalendarCache::~CalendarCache() { … } U_NAMESPACE_END #endif // !UCONFIG_NO_FORMATTING
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