1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software posted to USENET. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #if 0 35 #ifndef lint 36 static const char copyright[] = 37 "@(#) Copyright (c) 1989, 1993\n\ 38 The Regents of the University of California. All rights reserved.\n"; 39 #endif /* not lint */ 40 41 #endif 42 #include <sys/cdefs.h> 43 /* 44 * Phase of the Moon. Calculates the current phase of the moon. 45 * Based on routines from `Practical Astronomy with Your Calculator', 46 * by Duffett-Smith. Comments give the section from the book that 47 * particular piece of code was adapted from. 48 * 49 * -- Keith E. Brandt VIII 1984 50 * 51 */ 52 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <math.h> 56 #include <string.h> 57 #include <sysexits.h> 58 #include <time.h> 59 #include <unistd.h> 60 61 #include "calendar.h" 62 63 #ifndef PI 64 #define PI 3.14159265358979323846 65 #endif 66 #define EPOCH 85 67 #define EPSILONg 279.611371 /* solar ecliptic long at EPOCH */ 68 #define RHOg 282.680403 /* solar ecliptic long of perigee at EPOCH */ 69 #define ECCEN 0.01671542 /* solar orbit eccentricity */ 70 #define lzero 18.251907 /* lunar mean long at EPOCH */ 71 #define Pzero 192.917585 /* lunar mean long of perigee at EPOCH */ 72 #define Nzero 55.204723 /* lunar mean long of node at EPOCH */ 73 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0) 74 75 static void adj360(double *); 76 static double dtor(double); 77 static double potm(double onday); 78 static double potm_minute(double onday, int olddir); 79 80 void 81 pom(int year, double utcoffset, int *fms, int *nms) 82 { 83 double ffms[MAXMOONS]; 84 double fnms[MAXMOONS]; 85 int i, j; 86 87 fpom(year, utcoffset, ffms, fnms); 88 89 j = 0; 90 for (i = 0; ffms[i] != 0; i++) 91 fms[j++] = round(ffms[i]); 92 fms[i] = -1; 93 for (i = 0; fnms[i] != 0; i++) 94 nms[i] = round(fnms[i]); 95 nms[i] = -1; 96 } 97 98 void 99 fpom(int year, double utcoffset, double *ffms, double *fnms) 100 { 101 time_t tt; 102 struct tm GMT, tmd_today, tmd_tomorrow; 103 double days_today, days_tomorrow, today, tomorrow; 104 int cnt, d; 105 int yeardays; 106 int olddir, newdir; 107 double *pfnms, *pffms, t; 108 109 pfnms = fnms; 110 pffms = ffms; 111 112 /* 113 * We take the phase of the moon one second before and one second 114 * after midnight. 115 */ 116 memset(&tmd_today, 0, sizeof(tmd_today)); 117 tmd_today.tm_year = year - 1900; 118 tmd_today.tm_mon = 0; 119 tmd_today.tm_mday = -1; /* 31 December */ 120 tmd_today.tm_hour = 23; 121 tmd_today.tm_min = 59; 122 tmd_today.tm_sec = 59; 123 memset(&tmd_tomorrow, 0, sizeof(tmd_tomorrow)); 124 tmd_tomorrow.tm_year = year - 1900; 125 tmd_tomorrow.tm_mon = 0; 126 tmd_tomorrow.tm_mday = 0; /* 01 January */ 127 tmd_tomorrow.tm_hour = 0; 128 tmd_tomorrow.tm_min = 0; 129 tmd_tomorrow.tm_sec = 1; 130 131 tt = mktime(&tmd_today); 132 gmtime_r(&tt, &GMT); 133 yeardays = 0; 134 for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt) 135 yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR; 136 days_today = (GMT.tm_yday + 1) + ((GMT.tm_hour + 137 (GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) / 138 FHOURSPERDAY); 139 days_today += yeardays; 140 141 tt = mktime(&tmd_tomorrow); 142 gmtime_r(&tt, &GMT); 143 yeardays = 0; 144 for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt) 145 yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR; 146 days_tomorrow = (GMT.tm_yday + 1) + ((GMT.tm_hour + 147 (GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) / 148 FHOURSPERDAY); 149 days_tomorrow += yeardays; 150 151 today = potm(days_today); /* 30 December 23:59:59 */ 152 tomorrow = potm(days_tomorrow); /* 31 December 00:00:01 */ 153 olddir = today > tomorrow ? -1 : +1; 154 155 yeardays = 1 + (isleap(year) ? DAYSPERLEAPYEAR : DAYSPERYEAR); /* reuse */ 156 for (d = 0; d <= yeardays; d++) { 157 today = potm(days_today); 158 tomorrow = potm(days_tomorrow); 159 newdir = today > tomorrow ? -1 : +1; 160 if (olddir != newdir) { 161 t = potm_minute(days_today - 1, olddir) + 162 utcoffset / FHOURSPERDAY; 163 if (olddir == -1 && newdir == +1) { 164 *pfnms = d - 1 + t; 165 pfnms++; 166 } else if (olddir == +1 && newdir == -1) { 167 *pffms = d - 1 + t; 168 pffms++; 169 } 170 } 171 olddir = newdir; 172 days_today++; 173 days_tomorrow++; 174 } 175 *pffms = -1; 176 *pfnms = -1; 177 } 178 179 static double 180 potm_minute(double onday, int olddir) { 181 double period = FSECSPERDAY / 2.0; 182 double p1, p2; 183 double before, after; 184 int newdir; 185 186 // printf("---> days:%g olddir:%d\n", days, olddir); 187 188 p1 = onday + (period / SECSPERDAY); 189 period /= 2; 190 191 while (period > 30) { /* half a minute */ 192 // printf("period:%g - p1:%g - ", period, p1); 193 p2 = p1 + (2.0 / SECSPERDAY); 194 before = potm(p1); 195 after = potm(p2); 196 // printf("before:%10.10g - after:%10.10g\n", before, after); 197 newdir = before < after ? -1 : +1; 198 if (olddir != newdir) 199 p1 += (period / SECSPERDAY); 200 else 201 p1 -= (period / SECSPERDAY); 202 period /= 2; 203 // printf("newdir:%d - p1:%10.10f - period:%g\n", 204 // newdir, p1, period); 205 } 206 p1 -= floor(p1); 207 //exit(0); 208 return (p1); 209 } 210 211 /* 212 * potm -- 213 * return phase of the moon, as a percentage [0 ... 100] 214 */ 215 static double 216 potm(double onday) 217 { 218 double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime; 219 double A4, lprime, V, ldprime, D, Nm; 220 221 N = 360 * onday / 365.2422; /* sec 42 #3 */ 222 adj360(&N); 223 Msol = N + EPSILONg - RHOg; /* sec 42 #4 */ 224 adj360(&Msol); 225 Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 42 #5 */ 226 LambdaSol = N + Ec + EPSILONg; /* sec 42 #6 */ 227 adj360(&LambdaSol); 228 l = 13.1763966 * onday + lzero; /* sec 61 #4 */ 229 adj360(&l); 230 Mm = l - (0.1114041 * onday) - Pzero; /* sec 61 #5 */ 231 adj360(&Mm); 232 Nm = Nzero - (0.0529539 * onday); /* sec 61 #6 */ 233 adj360(&Nm); 234 Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 61 #7 */ 235 Ac = 0.1858 * sin(dtor(Msol)); /* sec 61 #8 */ 236 A3 = 0.37 * sin(dtor(Msol)); 237 Mmprime = Mm + Ev - Ac - A3; /* sec 61 #9 */ 238 Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 61 #10 */ 239 A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 61 #11 */ 240 lprime = l + Ev + Ec - Ac + A4; /* sec 61 #12 */ 241 V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 61 #13 */ 242 ldprime = lprime + V; /* sec 61 #14 */ 243 D = ldprime - LambdaSol; /* sec 63 #2 */ 244 return(50 * (1 - cos(dtor(D)))); /* sec 63 #3 */ 245 } 246 247 /* 248 * dtor -- 249 * convert degrees to radians 250 */ 251 static double 252 dtor(double deg) 253 { 254 255 return(deg * PI / 180); 256 } 257 258 /* 259 * adj360 -- 260 * adjust value so 0 <= deg <= 360 261 */ 262 static void 263 adj360(double *deg) 264 { 265 266 for (;;) 267 if (*deg < 0) 268 *deg += 360; 269 else if (*deg > 360) 270 *deg -= 360; 271 else 272 break; 273 } 274