/* This file is part of the kmoon application with explicit permission by the author Copyright (C) 1996 Christopher Osburn This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /* ** jd.c: ** 1996/02/11 ** ** Copyright 1996, Christopher Osburn, Lunar Outreach Services, ** Non-commercial usage license granted to all. ** ** convert a Julian Day number to a struct tm ** ** Parameter: ** double jd: Julian day number with fraction of day ** ** Returns: ** struct tm *event_date: Date-time group holding year, month, day, hour, ** and minute of the event */ #include #include time_t JDtoDate(double jd, struct tm *event_date) /* convert a Julian Date to a date-time group */ { long a, a1, z, b, c, d, e; double f, day; struct tm dummy; if ( !event_date ) event_date = &dummy; jd += 0.5; z = (long) jd; f = jd - z; if (z < 2299161) { a = z; } else { a1 = (long) ((z - 1867216.25) / 36524.25); a = z + 1 + a1 - (long)(a1 / 4); } b = a + 1524; c = (long)((b - 122.1) / 365.25); d = (long)(365.25 * c); e = (long)((b - d)/30.6001); day = b - d - (long)(30.6001 * e) + f; if (e < 14) { event_date->tm_mon = (e - 1) - 1; } else { event_date->tm_mon = (e - 13) - 1; } if (event_date->tm_mon > (2 - 1)) { event_date->tm_year = c - 4716 - 1900; } else { event_date->tm_year = c - 4715 - 1900; } event_date->tm_mday = (int)day; day -= event_date->tm_mday; day *= 24; event_date->tm_hour = (int)day; day -= event_date->tm_hour; day *= 60; event_date->tm_min = (int)day; day -= event_date->tm_min; day *= 60; event_date->tm_sec = (int)day; event_date->tm_isdst = -1; return mktime(event_date); } double DatetoJD(struct tm *event_date) /* convert a date-time group to a JD with fraction */ { int y, m; double d; int a, b; double jd; y = event_date->tm_year + 1900; m = event_date->tm_mon + 1; d = (double)(event_date->tm_mday) + (event_date->tm_hour / 24.0) + (event_date->tm_min / 1440.0) + (event_date->tm_sec / 86400.0); if (m == 1 || m == 2) { y--; m += 12; } a = (int)(y / 100); b = 2 - a + (int)(a / 4); if (y < 1583) if ((y < 1582) || (m < 10) || ((m == 10) && (d <= 15))) b = 0; jd = (long)(365.25 * (y + 4716)) + (long)(30.6001 * (m+1)) + d + b - 1524.5; return jd; } /* ** misc.h ** 1996/02/11 ** ** Copyright 1996, Christopher Osburn, Lunar Outreach Services, ** Non-commercial usage license granted to all. ** ** Miscellaneous routines for moon phase programs ** */ #include double torad(double x) /* convert x to radians */ { x = fmod(x, 360.0); /* normalize the angle */ return ((x) * 0.01745329251994329576); /* and return the result */ } /* ** moonphase.c ** 1996/02/11 ** ** Copyright 1996, Christopher Osburn, Lunar Outreach Services, ** Non-commercial usage license granted to all. ** ** calculate phase of the moon per Meeus Ch. 47 ** ** Parameters: ** int lun: phase parameter. This is the number of lunations ** since the New Moon of 2000 January 6. ** ** int phi: another phase parameter, selecting the phase of the ** moon. 0 = New, 1 = First TQtr, 2 = Full, 3 = Last TQtr ** ** Return: Apparent JD of the needed phase */ #include #include double moonphase(double k, int phi) { int i; /* iterator to be named later. Every program needs an i */ double T; /* time parameter, Julian Centuries since J2000 */ double JDE; /* Julian Ephemeris Day of phase event */ double E; /* Eccentricity anomaly */ double M; /* Sun's mean anomaly */ double M1; /* Moon's mean anomaly */ double F; /* Moon's argument of latitude */ double O; /* Moon's longitude of ascenfing node */ double A[15]; /* planetary arguments */ double W; /* added correction for quarter phases */ T = k / 1236.85; /* (47.3) */ /* this is the first approximation. all else is for style points! */ JDE = 2451550.09765 + (29.530588853 * k) /* (47.1) */ + T * T * (0.0001337 + T * (-0.000000150 + 0.00000000073 * T)); /* these are correction parameters used below */ E = 1.0 /* (45.6) */ + T * (-0.002516 + -0.0000074 * T); M = 2.5534 + 29.10535669 * k /* (47.4) */ + T * T * (-0.0000218 + -0.00000011 * T); M1 = 201.5643 + 385.81693528 * k /* (47.5) */ + T * T * (0.0107438 + T * (0.00001239 + -0.000000058 * T)); F = 160.7108 + 390.67050274 * k /* (47.6) */ + T * T * (-0.0016341 * T * (-0.00000227 + 0.000000011 * T)); O = 124.7746 - 1.56375580 * k /* (47.7) */ + T * T * (0.0020691 + 0.00000215 * T); /* planetary arguments */ A[0] = 0; /* unused! */ A[1] = 299.77 + 0.107408 * k - 0.009173 * T * T; A[2] = 251.88 + 0.016321 * k; A[3] = 251.83 + 26.651886 * k; A[4] = 349.42 + 36.412478 * k; A[5] = 84.66 + 18.206239 * k; A[6] = 141.74 + 53.303771 * k; A[7] = 207.14 + 2.453732 * k; A[8] = 154.84 + 7.306860 * k; A[9] = 34.52 + 27.261239 * k; A[10] = 207.19 + 0.121824 * k; A[11] = 291.34 + 1.844379 * k; A[12] = 161.72 + 24.198154 * k; A[13] = 239.56 + 25.513099 * k; A[14] = 331.55 + 3.592518 * k; /* all of the above crap must be made into radians!!! */ /* except for E... */ M = torad(M); M1 = torad(M1); F = torad(F); O = torad(O); /* all those planetary arguments, too! */ for (i=1; i<=14; i++) A[i] = torad(A[i]); /* ok, we have all the parameters, let's apply them to the JDE. (remember the JDE? this is a program about the JDE...) */ switch(phi) { /* a special case for each different phase. NOTE!, I'm not treating these in a 0123 order!!! Pay attention, there, you! */ case 0: /* New Moon */ JDE = JDE - 0.40720 * sin (M1) + 0.17241 * E * sin (M) + 0.01608 * sin (2.0 * M1) + 0.01039 * sin (2.0 * F) + 0.00739 * E * sin (M1 - M) - 0.00514 * E * sin (M1 + M) + 0.00208 * E * E * sin (2.0 * M) - 0.00111 * sin (M1 - 2.0 * F) - 0.00057 * sin (M1 + 2.0 * F) + 0.00056 * E * sin (2.0 * M1 + M) - 0.00042 * sin (3.0 * M1) + 0.00042 * E * sin (M + 2.0 * F) + 0.00038 * E * sin (M - 2.0 * F) - 0.00024 * E * sin (2.0 * M1 - M) - 0.00017 * sin (O) - 0.00007 * sin (M1 + 2.0 * M) + 0.00004 * sin (2.0 * M1 - 2.0 * F) + 0.00004 * sin (3.0 * M) + 0.00003 * sin (M1 + M - 2.0 * F) + 0.00003 * sin (2.0 * M1 + 2.0 * F) - 0.00003 * sin (M1 + M + 2.0 * F) + 0.00003 * sin (M1 - M + 2.0 * F) - 0.00002 * sin (M1 - M - 2.0 * F) - 0.00002 * sin (3.0 * M1 + M) + 0.00002 * sin (4.0 * M1); break; case 2: /* Full Moon */ JDE = JDE - 0.40614 * sin (M1) + 0.17302 * E * sin (M) + 0.01614 * sin (2.0 * M1) + 0.01043 * sin (2.0 * F) + 0.00734 * E * sin (M1 - M) - 0.00515 * E * sin (M1 + M) + 0.00209 * E * E * sin (2.0 * M) - 0.00111 * sin (M1 - 2.0 * F) - 0.00057 * sin (M1 + 2.0 * F) + 0.00056 * E * sin (2.0 * M1 + M) - 0.00042 * sin (3.0 * M1) + 0.00042 * E * sin (M + 2.0 * F) + 0.00038 * E * sin (M - 2.0 * F) - 0.00024 * E * sin (2.0 * M1 - M) - 0.00017 * sin (O) - 0.00007 * sin (M1 + 2.0 * M) + 0.00004 * sin (2.0 * M1 - 2.0 * F) + 0.00004 * sin (3.0 * M) + 0.00003 * sin (M1 + M - 2.0 * F) + 0.00003 * sin (2.0 * M1 + 2.0 * F) - 0.00003 * sin (M1 + M + 2.0 * F) + 0.00003 * sin (M1 - M + 2.0 * F) - 0.00002 * sin (M1 - M - 2.0 * F) - 0.00002 * sin (3.0 * M1 + M) + 0.00002 * sin (4.0 * M1); break; case 1: /* First Quarter */ case 3: /* Last Quarter */ JDE = JDE - 0.62801 * sin (M1) + 0.17172 * E * sin (M) - 0.01183 * E * sin (M1 + M) + 0.00862 * sin (2.0 * M1) + 0.00804 * sin (2.0 * F) + 0.00454 * E * sin (M1 - M) + 0.00204 * E * E * sin (2.0 * M) - 0.00180 * sin (M1 - 2.0 * F) - 0.00070 * sin (M1 + 2.0 * F) - 0.00040 * sin (3.0 * M1) - 0.00034 * E * sin (2.0 * M1 - M) + 0.00032 * E * sin (M + 2.0 * F) + 0.00032 * E * sin (M - 2.0 * F) - 0.00028 * E * E * sin (M1 + 2.0 * M) + 0.00027 * E * sin (2.0 * M1 + M) - 0.00017 * sin (O) - 0.00005 * sin (M1 - M - 2.0 * F) + 0.00004 * sin (2.0 * M1 + 2.0 * F) - 0.00004 * sin (M1 + M + 2.0 * F) + 0.00004 * sin (M1 - 2.0 * M) + 0.00003 * sin (M1 + M - 2.0 * F) + 0.00003 * sin (3.0 * M) + 0.00002 * sin (2.0 * M1 - 2.0 * F) + 0.00002 * sin (M1 - M + 2.0 * F) - 0.00002 * sin (3.0 * M1 + M); W = 0.00306 - 0.00038 * E * cos(M) + 0.00026 * cos(M1) - 0.00002 * cos(M1 - M) + 0.00002 * cos(M1 + M) + 0.00002 * cos(2.0 * F); if (phi == 3) W = -W; JDE += W; break; default: /* oops! */ fprintf(stderr, "The Moon has exploded!\n"); exit(1); break; /* unexecuted code */ } /* now there are some final correction to everything */ JDE = JDE + 0.000325 * sin(A[1]) + 0.000165 * sin(A[2]) + 0.000164 * sin(A[3]) + 0.000126 * sin(A[4]) + 0.000110 * sin(A[5]) + 0.000062 * sin(A[6]) + 0.000060 * sin(A[7]) + 0.000056 * sin(A[8]) + 0.000047 * sin(A[9]) + 0.000042 * sin(A[10]) + 0.000040 * sin(A[11]) + 0.000037 * sin(A[12]) + 0.000035 * sin(A[13]) + 0.000023 * sin(A[14]); return JDE; } #define LUNATION_OFFSET 953 double moonphasebylunation(int lun, int phi) { double k; k = lun - LUNATION_OFFSET + phi / 4.0; return moonphase(k, phi); }