diff --git a/src/SunRiSet.cpp b/src/SunRiSet.cpp deleted file mode 100644 index 12822a0..0000000 --- a/src/SunRiSet.cpp +++ /dev/null @@ -1,261 +0,0 @@ -// Implementation of Sun Rise and Set Times based on SUNRISET.C by Paul Schlyter 1989-2013. -// Original C code available at https://www.stjarnhimlen.se/comp/sunriset.c (copy in sunriset.c.txt) -// was modified for C++ and OpenKNX. -// For detailed explaination/documentation see https://www.stjarnhimlen.se/comp/riset.html - -#include "SunRiSet.h" -#include "Arduino.h" -#include - - -/* -void SunRiSet::convertToLocalTime(double iTime, sTime *eTime) -{ - eTime->hour = (int)floor(iTime); - eTime->minute = (int)(60 * (iTime - floor(iTime))); - eTime->hour += mTimezone + ((mIsSummertime) ? 1 : 0); -} - -void SunRiSet::calculateSunriseSunset() -{ - double rise, set; - // sunrise/sunset calculation - sunRiseSet(getYear(), getMonth(), getDay(), - mLongitude, mLatitude, -35.0 / 60.0, 1, &rise, &set); - convertToLocalTime(rise, &mSunrise); - convertToLocalTime(set, &mSunset); -} - -sTime *SunRiSet::getSunInfo(uint8_t iSunInfo) -{ - if (iSunInfo == SUN_SUNRISE) - return &mSunrise; - else if (iSunInfo == SUN_SUNSET) - return &mSunset; - else - return NULL; -} - -void SunRiSet::getSunDegree(uint8_t iSunInfo, double iDegree, sTime *eSun) -{ - double rise, set; - // sunrise/sunset calculation - sunRiseSet(getYear(), getMonth(), getDay(), - mLongitude, mLatitude, iDegree, 0, &rise, &set); - if (iSunInfo == SUN_SUNRISE) - convertToLocalTime(rise, eSun); - else if (iSunInfo == SUN_SUNSET) - convertToLocalTime(set, eSun); -} -*/ - - -#pragma region SUNRISET - -/***************************************************************************/ -/* Note: year,month,date = calendar date, 1801-2099 only. */ -/* Eastern longitude positive, Western longitude negative */ -/* Northern latitude positive, Southern latitude negative */ -/* The longitude value IS critical in this function! */ -/* altit = the altitude which the Sun should cross */ -/* Set to -35/60 degrees for rise/set, -6 degrees */ -/* for civil, -12 degrees for nautical and -18 */ -/* degrees for astronomical twilight. */ -/* upper_limb: non-zero -> upper limb, zero -> center */ -/* Set to non-zero (e.g. 1) when computing rise/set */ -/* times, and to zero when computing start/end of */ -/* twilight. */ -/* *rise = where to store the rise time */ -/* *set = where to store the set time */ -/* Both times are relative to the specified altitude, */ -/* and thus this function can be used to compute */ -/* various twilight times, as well as rise/set times */ -/* Return value: 0 = sun rises/sets this day, times stored at */ -/* *trise and *tset. */ -/* +1 = sun above the specified "horizon" 24 hours. */ -/* *trise set to time when the sun is at south, */ -/* minus 12 hours while *tset is set to the south */ -/* time plus 12 hours. "Day" length = 24 hours */ -/* -1 = sun is below the specified "horizon" 24 hours */ -/* "Day" length = 0 hours, *trise and *tset are */ -/* both set to the time when the sun is at south. */ -/* */ -/**********************************************************************/ -int SunRiSet::sunRiseSet(int year, int month, int day, double lon, double lat, - double altit, int upper_limb, double *trise, double *tset) -{ - double d, /* Days since 2000 Jan 0.0 (negative before) */ - sr, /* Solar distance, astronomical units */ - sRA, /* Sun's Right Ascension */ - sdec, /* Sun's declination */ - sradius, /* Sun's apparent radius */ - t, /* Diurnal arc */ - tsouth, /* Time when Sun is at south */ - sidtime; /* Local sidereal time */ - - int rc = 0; /* Return cde from function - usually 0 */ - - /* Compute d of 12h local mean solar time */ - d = days_since_2000_Jan_0(year, month, day) + 0.5 - lon / 360.0; - - /* Compute the local sidereal time of this moment */ - sidtime = revolution(GMST0(d) + 180.0 + lon); - - /* Compute Sun's RA, Decl and distance at this moment */ - sunRadDec(d, &sRA, &sdec, &sr); - - /* Compute time when Sun is at south - in hours UT */ - tsouth = 12.0 - rev180(sidtime - sRA) / 15.0; - - /* Compute the Sun's apparent radius in degrees */ - sradius = 0.2666 / sr; - - /* Do correction to upper limb, if necessary */ - if (upper_limb) - altit -= sradius; - - /* Compute the diurnal arc that the Sun traverses to reach */ - /* the specified altitude altit: */ - { - double cost; - cost = (sind(altit) - sind(lat) * sind(sdec)) / - (cosd(lat) * cosd(sdec)); - if (cost >= 1.0) - rc = -1, t = 0.0; /* Sun always below altit */ - else if (cost <= -1.0) - rc = +1, t = 12.0; /* Sun always above altit */ - else - t = acosd(cost) / 15.0; /* The diurnal arc, hours */ - } - - /* Store rise and set times - in hours UT */ - *trise = tsouth - t; - *tset = tsouth + t; - - return rc; -} - -/******************************************************/ -/* Computes the Sun's ecliptic longitude and distance */ -/* at an instant given in d, number of days since */ -/* 2000 Jan 0.0. The Sun's ecliptic latitude is not */ -/* computed, since it's always very near 0. */ -/******************************************************/ -void SunRiSet::sunPos(double d, double *lon, double *r) -{ - double M, /* Mean anomaly of the Sun */ - w, /* Mean longitude of perihelion */ - /* Note: Sun's mean longitude = M + w */ - e, /* Eccentricity of Earth's orbit */ - E, /* Eccentric anomaly */ - x, y, /* x, y coordinates in orbit */ - v; /* True anomaly */ - - /* Compute mean elements */ - M = revolution(356.0470 + 0.9856002585 * d); - w = 282.9404 + 4.70935E-5 * d; - e = 0.016709 - 1.151E-9 * d; - - /* Compute true longitude and radius vector */ - E = M + e * RADEG * sind(M) * (1.0 + e * cosd(M)); - x = cosd(E) - e; - y = sqrt(1.0 - e * e) * sind(E); - *r = sqrt(x * x + y * y); /* Solar distance */ - v = atan2d(y, x); /* True anomaly */ - *lon = v + w; /* True solar longitude */ - if (*lon >= 360.0) - *lon -= 360.0; /* Make it 0..360 degrees */ -} - -/******************************************************/ -/* Computes the Sun's equatorial coordinates RA, Decl */ -/* and also its distance, at an instant given in d, */ -/* the number of days since 2000 Jan 0.0. */ -/******************************************************/ -void SunRiSet::sunRadDec(double d, double *RA, double *dec, double *r) -{ - double lon, obl_ecl, x, y, z; - - /* Compute Sun's ecliptical coordinates */ - sunPos(d, &lon, r); - - /* Compute ecliptic rectangular coordinates (z=0) */ - x = *r * cosd(lon); - y = *r * sind(lon); - - /* Compute obliquity of ecliptic (inclination of Earth's axis) */ - obl_ecl = 23.4393 - 3.563E-7 * d; - - /* Convert to equatorial rectangular coordinates - x is unchanged */ - z = y * sind(obl_ecl); - y = y * cosd(obl_ecl); - - /* Convert to spherical coordinates */ - *RA = atan2d(y, x); - *dec = atan2d(z, sqrt(x * x + y * y)); -} - -/******************************************************************/ -/* This function reduces any angle to within the first revolution */ -/* by subtracting or adding even multiples of 360.0 until the */ -/* result is >= 0.0 and < 360.0 */ -/******************************************************************/ - -#define INV360 (1.0 / 360.0) - -/*****************************************/ -/* Reduce angle to within 0..360 degrees */ -/*****************************************/ -double SunRiSet::revolution(double x) -{ - return (x - 360.0 * floor(x * INV360)); -} - -/*********************************************/ -/* Reduce angle to within +180..+180 degrees */ -/*********************************************/ -double SunRiSet::rev180(double x) -{ - return (x - 360.0 * floor(x * INV360 + 0.5)); -} - -/*******************************************************************/ -/* This function computes GMST0, the Greenwich Mean Sidereal Time */ -/* at 0h UT (i.e. the sidereal time at the Greenwhich meridian at */ -/* 0h UT). GMST is then the sidereal time at Greenwich at any */ -/* time of the day. I've generalized GMST0 as well, and define it */ -/* as: GMST0 = GMST - UT -- this allows GMST0 to be computed at */ -/* other times than 0h UT as well. While this sounds somewhat */ -/* contradictory, it is very practical: instead of computing */ -/* GMST like: */ -/* */ -/* GMST = (GMST0) + UT * (366.2422/365.2422) */ -/* */ -/* where (GMST0) is the GMST last time UT was 0 hours, one simply */ -/* computes: */ -/* */ -/* GMST = GMST0 + UT */ -/* */ -/* where GMST0 is the GMST "at 0h UT" but at the current moment! */ -/* Defined in this way, GMST0 will increase with about 4 min a */ -/* day. It also happens that GMST0 (in degrees, 1 hr = 15 degr) */ -/* is equal to the Sun's mean longitude plus/minus 180 degrees! */ -/* (if we neglect aberration, which amounts to 20 seconds of arc */ -/* or 1.33 seconds of time) */ -/* */ -/*******************************************************************/ - -double SunRiSet::GMST0(double d) -{ - double sidtim0; - /* Sidtime at 0h UT = L (Sun's mean longitude) + 180.0 degr */ - /* L = M + w, as defined in sunpos(). Since I'm too lazy to */ - /* add these numbers, I'll let the C compiler do it for me. */ - /* Any decent C compiler will add the constants at compile */ - /* time, imposing no runtime or code overhead. */ - sidtim0 = revolution((180.0 + 356.0470 + 282.9404) + - (0.9856002585 + 4.70935E-5) * d); - return sidtim0; -} /* GMST0 */ - -#pragma endregion diff --git a/src/SunRiSet.h b/src/SunRiSet.h deleted file mode 100644 index 569793c..0000000 --- a/src/SunRiSet.h +++ /dev/null @@ -1,86 +0,0 @@ -// Implementation of Sun Rise and Set Times based on SUNRISET.C by Paul Schlyter 1989-2013. -// Original C code available at https://www.stjarnhimlen.se/comp/sunriset.c (copy in sunriset.c.txt) -// was modified for C++ and OpenKNX. -// For detailed explaination/documentation see https://www.stjarnhimlen.se/comp/riset.html - -#pragma once - - -#include -#include -#include - - -// #define SUN_SUNRISE 0x00 -// #define SUN_SUNSET 0x01 - -/* -struct sTime -{ - int8_t minute; - int8_t hour; -}; - -struct sDay -{ - int8_t day; - int8_t month; -}; -*/ - -class SunRiSet -{ - - - protected: - /* - sTime mSunrise; - sTime mSunset; - void calculateSunriseSunset(); - void convertToLocalTime(double iTime, sTime *eTime); - */ - - public: - static int sunRiseSet(int year, int month, int day, double lon, double lat, - double altit, int upper_limb, double *rise, double *set); - private: - static void sunPos(double d, double *lon, double *r); - static void sunRadDec(double d, double *RA, double *dec, double *r); - static double revolution(double x); - static double rev180(double x); - static double GMST0(double d); - - /* - float mLongitude; - float mLatitude; - - sTime *getSunInfo(uint8_t iSunInfo); - void getSunDegree(uint8_t iSunInfo, double iDegree, sTime *eSun); - */ -}; - -/* A macro to compute the number of days elapsed since 2000 Jan 0.0 */ -/* (which is equal to 1999 Dec 31, 0h UT) */ - -#define days_since_2000_Jan_0(y, m, d) \ - (367L * (y) - ((7 * ((y) + (((m) + 9) / 12))) / 4) + ((275 * (m)) / 9) + (d)-730530L) - -/* Some conversion factors between radians and degrees */ - -// #ifndef PI -// #define PI 3.1415926535897932384 -// #endif - -#define RADEG (180.0 / PI) -#define DEGRAD (PI / 180.0) - -/* The trigonometric functions in degrees */ - -#define sind(x) sin((x)*DEGRAD) -#define cosd(x) cos((x)*DEGRAD) -#define tand(x) tan((x)*DEGRAD) - -#define atand(x) (RADEG * atan(x)) -#define asind(x) (RADEG * asin(x)) -#define acosd(x) (RADEG * acos(x)) -#define atan2d(y, x) (RADEG * atan2(y, x)) diff --git a/src/Timer.cpp b/src/Timer.cpp index d5e3db9..5c4493d 100644 --- a/src/Timer.cpp +++ b/src/Timer.cpp @@ -1,5 +1,5 @@ #include "Timer.h" -#include "SunRiSet.h" +#include "OpenKNX/Sun/SunRiseAndSet.h" #include "Arduino.h" #include @@ -131,14 +131,14 @@ bool Timer::loop() return lMinuteChanged; } -// TODO: Check Migration to Common Time / SunCalculation +// TODO: Fully migrate to Common Time / SunCalculation, but keep in mind we "time travel" in LOG for restore void Timer::convertToLocalTime(double iTime, sTime *eTime) { OpenKNX::TimeOnly localTime = OpenKNX::DateTime( getYear(), getMonth(), getDay(), - (int)floor(iTime), + (int)floor(iTime), // Important: New Constructor with `int` in Param Signature required! (int)(60 * (iTime - floor(iTime))), 0, OpenKNX::DateTimeTypeUTC @@ -152,7 +152,7 @@ void Timer::calculateSunriseSunset() { double rise, set; // sunrise/sunset calculation - SunRiSet::sunRiseSet(getYear(), getMonth(), getDay(), + OpenKNX::Sun::SunRiseAndSet::sunRiseSet(getYear(), getMonth(), getDay(), mLongitude, mLatitude, -35.0 / 60.0, 1, &rise, &set); convertToLocalTime(rise, &mSunrise); convertToLocalTime(set, &mSunset); @@ -211,7 +211,7 @@ void Timer::getSunDegree(uint8_t iSunInfo, double iDegree, sTime *eSun) { double rise, set; // sunrise/sunset calculation - SunRiSet::sunRiseSet(getYear(), getMonth(), getDay(), + OpenKNX::Sun::SunRiseAndSet::sunRiseSet(getYear(), getMonth(), getDay(), mLongitude, mLatitude, iDegree, 0, &rise, &set); if (iSunInfo == SUN_SUNRISE) convertToLocalTime(rise, eSun); diff --git a/src/sunriset.c.txt b/src/sunriset.c.txt deleted file mode 100644 index 16afbdd..0000000 --- a/src/sunriset.c.txt +++ /dev/null @@ -1,518 +0,0 @@ -/* +++Date last modified: 05-Jul-1997 */ -/* Updated comments, 05-Aug-2013 */ - -/* - -SUNRISET.C - computes Sun rise/set times, start/end of twilight, and - the length of the day at any date and latitude - -Written as DAYLEN.C, 1989-08-16 - -Modified to SUNRISET.C, 1992-12-01 - -(c) Paul Schlyter, 1989, 1992 - -Released to the public domain by Paul Schlyter, December 1992 - -*/ - - -#include -#include - - -/* A macro to compute the number of days elapsed since 2000 Jan 0.0 */ -/* (which is equal to 1999 Dec 31, 0h UT) */ - -#define days_since_2000_Jan_0(y,m,d) \ - (367L*(y)-((7*((y)+(((m)+9)/12)))/4)+((275*(m))/9)+(d)-730530L) - -/* Some conversion factors between radians and degrees */ - -#ifndef PI - #define PI 3.1415926535897932384 -#endif - -#define RADEG ( 180.0 / PI ) -#define DEGRAD ( PI / 180.0 ) - -/* The trigonometric functions in degrees */ - -#define sind(x) sin((x)*DEGRAD) -#define cosd(x) cos((x)*DEGRAD) -#define tand(x) tan((x)*DEGRAD) - -#define atand(x) (RADEG*atan(x)) -#define asind(x) (RADEG*asin(x)) -#define acosd(x) (RADEG*acos(x)) -#define atan2d(y,x) (RADEG*atan2(y,x)) - - -/* Following are some macros around the "workhorse" function __daylen__ */ -/* They mainly fill in the desired values for the reference altitude */ -/* below the horizon, and also selects whether this altitude should */ -/* refer to the Sun's center or its upper limb. */ - - -/* This macro computes the length of the day, from sunrise to sunset. */ -/* Sunrise/set is considered to occur when the Sun's upper limb is */ -/* 35 arc minutes below the horizon (this accounts for the refraction */ -/* of the Earth's atmosphere). */ -#define day_length(year,month,day,lon,lat) \ - __daylen__( year, month, day, lon, lat, -35.0/60.0, 1 ) - -/* This macro computes the length of the day, including civil twilight. */ -/* Civil twilight starts/ends when the Sun's center is 6 degrees below */ -/* the horizon. */ -#define day_civil_twilight_length(year,month,day,lon,lat) \ - __daylen__( year, month, day, lon, lat, -6.0, 0 ) - -/* This macro computes the length of the day, incl. nautical twilight. */ -/* Nautical twilight starts/ends when the Sun's center is 12 degrees */ -/* below the horizon. */ -#define day_nautical_twilight_length(year,month,day,lon,lat) \ - __daylen__( year, month, day, lon, lat, -12.0, 0 ) - -/* This macro computes the length of the day, incl. astronomical twilight. */ -/* Astronomical twilight starts/ends when the Sun's center is 18 degrees */ -/* below the horizon. */ -#define day_astronomical_twilight_length(year,month,day,lon,lat) \ - __daylen__( year, month, day, lon, lat, -18.0, 0 ) - - -/* This macro computes times for sunrise/sunset. */ -/* Sunrise/set is considered to occur when the Sun's upper limb is */ -/* 35 arc minutes below the horizon (this accounts for the refraction */ -/* of the Earth's atmosphere). */ -#define sun_rise_set(year,month,day,lon,lat,rise,set) \ - __sunriset__( year, month, day, lon, lat, -35.0/60.0, 1, rise, set ) - -/* This macro computes the start and end times of civil twilight. */ -/* Civil twilight starts/ends when the Sun's center is 6 degrees below */ -/* the horizon. */ -#define civil_twilight(year,month,day,lon,lat,start,end) \ - __sunriset__( year, month, day, lon, lat, -6.0, 0, start, end ) - -/* This macro computes the start and end times of nautical twilight. */ -/* Nautical twilight starts/ends when the Sun's center is 12 degrees */ -/* below the horizon. */ -#define nautical_twilight(year,month,day,lon,lat,start,end) \ - __sunriset__( year, month, day, lon, lat, -12.0, 0, start, end ) - -/* This macro computes the start and end times of astronomical twilight. */ -/* Astronomical twilight starts/ends when the Sun's center is 18 degrees */ -/* below the horizon. */ -#define astronomical_twilight(year,month,day,lon,lat,start,end) \ - __sunriset__( year, month, day, lon, lat, -18.0, 0, start, end ) - - -/* Function prototypes */ - -double __daylen__( int year, int month, int day, double lon, double lat, - double altit, int upper_limb ); - -int __sunriset__( int year, int month, int day, double lon, double lat, - double altit, int upper_limb, double *rise, double *set ); - -void sunpos( double d, double *lon, double *r ); - -void sun_RA_dec( double d, double *RA, double *dec, double *r ); - -double revolution( double x ); - -double rev180( double x ); - -double GMST0( double d ); - - - -/* A small test program */ - -main() -{ - int year,month,day; - double lon, lat; - double daylen, civlen, nautlen, astrlen; - double rise, set, civ_start, civ_end, naut_start, naut_end, - astr_start, astr_end; - int rs, civ, naut, astr; - char buf[80]; - - printf( "Longitude (+ is east) and latitude (+ is north) : " ); - fgets(buf, 80, stdin); - sscanf(buf, "%lf %lf", &lon, &lat ); - - for(;;) - { - printf( "Input date ( yyyy mm dd ) (ctrl-C exits): " ); - fgets(buf, 80, stdin); - sscanf(buf, "%d %d %d", &year, &month, &day ); - - daylen = day_length(year,month,day,lon,lat); - civlen = day_civil_twilight_length(year,month,day,lon,lat); - nautlen = day_nautical_twilight_length(year,month,day,lon,lat); - astrlen = day_astronomical_twilight_length(year,month,day, - lon,lat); - - printf( "Day length: %5.2f hours\n", daylen ); - printf( "With civil twilight %5.2f hours\n", civlen ); - printf( "With nautical twilight %5.2f hours\n", nautlen ); - printf( "With astronomical twilight %5.2f hours\n", astrlen ); - printf( "Length of twilight: civil %5.2f hours\n", - (civlen-daylen)/2.0); - printf( " nautical %5.2f hours\n", - (nautlen-daylen)/2.0); - printf( " astronomical %5.2f hours\n", - (astrlen-daylen)/2.0); - - rs = sun_rise_set ( year, month, day, lon, lat, - &rise, &set ); - civ = civil_twilight ( year, month, day, lon, lat, - &civ_start, &civ_end ); - naut = nautical_twilight ( year, month, day, lon, lat, - &naut_start, &naut_end ); - astr = astronomical_twilight( year, month, day, lon, lat, - &astr_start, &astr_end ); - - printf( "Sun at south %5.2fh UT\n", (rise+set)/2.0 ); - - switch( rs ) - { - case 0: - printf( "Sun rises %5.2fh UT, sets %5.2fh UT\n", - rise, set ); - break; - case +1: - printf( "Sun above horizon\n" ); - break; - case -1: - printf( "Sun below horizon\n" ); - break; - } - - switch( civ ) - { - case 0: - printf( "Civil twilight starts %5.2fh, " - "ends %5.2fh UT\n", civ_start, civ_end ); - break; - case +1: - printf( "Never darker than civil twilight\n" ); - break; - case -1: - printf( "Never as bright as civil twilight\n" ); - break; - } - - switch( naut ) - { - case 0: - printf( "Nautical twilight starts %5.2fh, " - "ends %5.2fh UT\n", naut_start, naut_end ); - break; - case +1: - printf( "Never darker than nautical twilight\n" ); - break; - case -1: - printf( "Never as bright as nautical twilight\n" ); - break; - } - - switch( astr ) - { - case 0: - printf( "Astronomical twilight starts %5.2fh, " - "ends %5.2fh UT\n", astr_start, astr_end ); - break; - case +1: - printf( "Never darker than astronomical twilight\n" ); - break; - case -1: - printf( "Never as bright as astronomical twilight\n" ); - break; - } - return 0; - } -} - - -/* The "workhorse" function for sun rise/set times */ - -int __sunriset__( int year, int month, int day, double lon, double lat, - double altit, int upper_limb, double *trise, double *tset ) -/***************************************************************************/ -/* Note: year,month,date = calendar date, 1801-2099 only. */ -/* Eastern longitude positive, Western longitude negative */ -/* Northern latitude positive, Southern latitude negative */ -/* The longitude value IS critical in this function! */ -/* altit = the altitude which the Sun should cross */ -/* Set to -35/60 degrees for rise/set, -6 degrees */ -/* for civil, -12 degrees for nautical and -18 */ -/* degrees for astronomical twilight. */ -/* upper_limb: non-zero -> upper limb, zero -> center */ -/* Set to non-zero (e.g. 1) when computing rise/set */ -/* times, and to zero when computing start/end of */ -/* twilight. */ -/* *rise = where to store the rise time */ -/* *set = where to store the set time */ -/* Both times are relative to the specified altitude, */ -/* and thus this function can be used to compute */ -/* various twilight times, as well as rise/set times */ -/* Return value: 0 = sun rises/sets this day, times stored at */ -/* *trise and *tset. */ -/* +1 = sun above the specified "horizon" 24 hours. */ -/* *trise set to time when the sun is at south, */ -/* minus 12 hours while *tset is set to the south */ -/* time plus 12 hours. "Day" length = 24 hours */ -/* -1 = sun is below the specified "horizon" 24 hours */ -/* "Day" length = 0 hours, *trise and *tset are */ -/* both set to the time when the sun is at south. */ -/* */ -/**********************************************************************/ -{ - double d, /* Days since 2000 Jan 0.0 (negative before) */ - sr, /* Solar distance, astronomical units */ - sRA, /* Sun's Right Ascension */ - sdec, /* Sun's declination */ - sradius, /* Sun's apparent radius */ - t, /* Diurnal arc */ - tsouth, /* Time when Sun is at south */ - sidtime; /* Local sidereal time */ - - int rc = 0; /* Return cde from function - usually 0 */ - - /* Compute d of 12h local mean solar time */ - d = days_since_2000_Jan_0(year,month,day) + 0.5 - lon/360.0; - - /* Compute the local sidereal time of this moment */ - sidtime = revolution( GMST0(d) + 180.0 + lon ); - - /* Compute Sun's RA, Decl and distance at this moment */ - sun_RA_dec( d, &sRA, &sdec, &sr ); - - /* Compute time when Sun is at south - in hours UT */ - tsouth = 12.0 - rev180(sidtime - sRA)/15.0; - - /* Compute the Sun's apparent radius in degrees */ - sradius = 0.2666 / sr; - - /* Do correction to upper limb, if necessary */ - if ( upper_limb ) - altit -= sradius; - - /* Compute the diurnal arc that the Sun traverses to reach */ - /* the specified altitude altit: */ - { - double cost; - cost = ( sind(altit) - sind(lat) * sind(sdec) ) / - ( cosd(lat) * cosd(sdec) ); - if ( cost >= 1.0 ) - rc = -1, t = 0.0; /* Sun always below altit */ - else if ( cost <= -1.0 ) - rc = +1, t = 12.0; /* Sun always above altit */ - else - t = acosd(cost)/15.0; /* The diurnal arc, hours */ - } - - /* Store rise and set times - in hours UT */ - *trise = tsouth - t; - *tset = tsouth + t; - - return rc; -} /* __sunriset__ */ - - - -/* The "workhorse" function */ - - -double __daylen__( int year, int month, int day, double lon, double lat, - double altit, int upper_limb ) -/**********************************************************************/ -/* Note: year,month,date = calendar date, 1801-2099 only. */ -/* Eastern longitude positive, Western longitude negative */ -/* Northern latitude positive, Southern latitude negative */ -/* The longitude value is not critical. Set it to the correct */ -/* longitude if you're picky, otherwise set to to, say, 0.0 */ -/* The latitude however IS critical - be sure to get it correct */ -/* altit = the altitude which the Sun should cross */ -/* Set to -35/60 degrees for rise/set, -6 degrees */ -/* for civil, -12 degrees for nautical and -18 */ -/* degrees for astronomical twilight. */ -/* upper_limb: non-zero -> upper limb, zero -> center */ -/* Set to non-zero (e.g. 1) when computing day length */ -/* and to zero when computing day+twilight length. */ -/**********************************************************************/ -{ - double d, /* Days since 2000 Jan 0.0 (negative before) */ - obl_ecl, /* Obliquity (inclination) of Earth's axis */ - sr, /* Solar distance, astronomical units */ - slon, /* True solar longitude */ - sin_sdecl, /* Sine of Sun's declination */ - cos_sdecl, /* Cosine of Sun's declination */ - sradius, /* Sun's apparent radius */ - t; /* Diurnal arc */ - - /* Compute d of 12h local mean solar time */ - d = days_since_2000_Jan_0(year,month,day) + 0.5 - lon/360.0; - - /* Compute obliquity of ecliptic (inclination of Earth's axis) */ - obl_ecl = 23.4393 - 3.563E-7 * d; - - /* Compute Sun's ecliptic longitude and distance */ - sunpos( d, &slon, &sr ); - - /* Compute sine and cosine of Sun's declination */ - sin_sdecl = sind(obl_ecl) * sind(slon); - cos_sdecl = sqrt( 1.0 - sin_sdecl * sin_sdecl ); - - /* Compute the Sun's apparent radius, degrees */ - sradius = 0.2666 / sr; - - /* Do correction to upper limb, if necessary */ - if ( upper_limb ) - altit -= sradius; - - /* Compute the diurnal arc that the Sun traverses to reach */ - /* the specified altitude altit: */ - { - double cost; - cost = ( sind(altit) - sind(lat) * sin_sdecl ) / - ( cosd(lat) * cos_sdecl ); - if ( cost >= 1.0 ) - t = 0.0; /* Sun always below altit */ - else if ( cost <= -1.0 ) - t = 24.0; /* Sun always above altit */ - else t = (2.0/15.0) * acosd(cost); /* The diurnal arc, hours */ - } - return t; -} /* __daylen__ */ - - -/* This function computes the Sun's position at any instant */ - -void sunpos( double d, double *lon, double *r ) -/******************************************************/ -/* Computes the Sun's ecliptic longitude and distance */ -/* at an instant given in d, number of days since */ -/* 2000 Jan 0.0. The Sun's ecliptic latitude is not */ -/* computed, since it's always very near 0. */ -/******************************************************/ -{ - double M, /* Mean anomaly of the Sun */ - w, /* Mean longitude of perihelion */ - /* Note: Sun's mean longitude = M + w */ - e, /* Eccentricity of Earth's orbit */ - E, /* Eccentric anomaly */ - x, y, /* x, y coordinates in orbit */ - v; /* True anomaly */ - - /* Compute mean elements */ - M = revolution( 356.0470 + 0.9856002585 * d ); - w = 282.9404 + 4.70935E-5 * d; - e = 0.016709 - 1.151E-9 * d; - - /* Compute true longitude and radius vector */ - E = M + e * RADEG * sind(M) * ( 1.0 + e * cosd(M) ); - x = cosd(E) - e; - y = sqrt( 1.0 - e*e ) * sind(E); - *r = sqrt( x*x + y*y ); /* Solar distance */ - v = atan2d( y, x ); /* True anomaly */ - *lon = v + w; /* True solar longitude */ - if ( *lon >= 360.0 ) - *lon -= 360.0; /* Make it 0..360 degrees */ -} - -void sun_RA_dec( double d, double *RA, double *dec, double *r ) -/******************************************************/ -/* Computes the Sun's equatorial coordinates RA, Decl */ -/* and also its distance, at an instant given in d, */ -/* the number of days since 2000 Jan 0.0. */ -/******************************************************/ -{ - double lon, obl_ecl, x, y, z; - - /* Compute Sun's ecliptical coordinates */ - sunpos( d, &lon, r ); - - /* Compute ecliptic rectangular coordinates (z=0) */ - x = *r * cosd(lon); - y = *r * sind(lon); - - /* Compute obliquity of ecliptic (inclination of Earth's axis) */ - obl_ecl = 23.4393 - 3.563E-7 * d; - - /* Convert to equatorial rectangular coordinates - x is unchanged */ - z = y * sind(obl_ecl); - y = y * cosd(obl_ecl); - - /* Convert to spherical coordinates */ - *RA = atan2d( y, x ); - *dec = atan2d( z, sqrt(x*x + y*y) ); - -} /* sun_RA_dec */ - - -/******************************************************************/ -/* This function reduces any angle to within the first revolution */ -/* by subtracting or adding even multiples of 360.0 until the */ -/* result is >= 0.0 and < 360.0 */ -/******************************************************************/ - -#define INV360 ( 1.0 / 360.0 ) - -double revolution( double x ) -/*****************************************/ -/* Reduce angle to within 0..360 degrees */ -/*****************************************/ -{ - return( x - 360.0 * floor( x * INV360 ) ); -} /* revolution */ - -double rev180( double x ) -/*********************************************/ -/* Reduce angle to within +180..+180 degrees */ -/*********************************************/ -{ - return( x - 360.0 * floor( x * INV360 + 0.5 ) ); -} /* revolution */ - - -/*******************************************************************/ -/* This function computes GMST0, the Greenwich Mean Sidereal Time */ -/* at 0h UT (i.e. the sidereal time at the Greenwhich meridian at */ -/* 0h UT). GMST is then the sidereal time at Greenwich at any */ -/* time of the day. I've generalized GMST0 as well, and define it */ -/* as: GMST0 = GMST - UT -- this allows GMST0 to be computed at */ -/* other times than 0h UT as well. While this sounds somewhat */ -/* contradictory, it is very practical: instead of computing */ -/* GMST like: */ -/* */ -/* GMST = (GMST0) + UT * (366.2422/365.2422) */ -/* */ -/* where (GMST0) is the GMST last time UT was 0 hours, one simply */ -/* computes: */ -/* */ -/* GMST = GMST0 + UT */ -/* */ -/* where GMST0 is the GMST "at 0h UT" but at the current moment! */ -/* Defined in this way, GMST0 will increase with about 4 min a */ -/* day. It also happens that GMST0 (in degrees, 1 hr = 15 degr) */ -/* is equal to the Sun's mean longitude plus/minus 180 degrees! */ -/* (if we neglect aberration, which amounts to 20 seconds of arc */ -/* or 1.33 seconds of time) */ -/* */ -/*******************************************************************/ - -double GMST0( double d ) -{ - double sidtim0; - /* Sidtime at 0h UT = L (Sun's mean longitude) + 180.0 degr */ - /* L = M + w, as defined in sunpos(). Since I'm too lazy to */ - /* add these numbers, I'll let the C compiler do it for me. */ - /* Any decent C compiler will add the constants at compile */ - /* time, imposing no runtime or code overhead. */ - sidtim0 = revolution( ( 180.0 + 356.0470 + 282.9404 ) + - ( 0.9856002585 + 4.70935E-5 ) * d ); - return sidtim0; -} /* GMST0 */