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 #ifndef lint 42 static const char sccsid[] = "@(#)pom.c 8.1 (Berkeley) 5/31/93"; 43 #endif /* not lint */ 44 #endif 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 47 48 /* 49 * Phase of the Moon. Calculates the current phase of the moon. 50 * Based on routines from `Practical Astronomy with Your Calculator', 51 * by Duffett-Smith. Comments give the section from the book that 52 * particular piece of code was adapted from. 53 * 54 * -- Keith E. Brandt VIII 1984 55 * 56 */ 57 58 #include <stdio.h> 59 #include <stdlib.h> 60 #include <math.h> 61 #include <string.h> 62 #include <sysexits.h> 63 #include <time.h> 64 #include <unistd.h> 65 66 #include "calendar.h" 67 68 #ifndef PI 69 #define PI 3.14159265358979323846 70 #endif 71 #define EPOCH 85 72 #define EPSILONg 279.611371 /* solar ecliptic long at EPOCH */ 73 #define RHOg 282.680403 /* solar ecliptic long of perigee at EPOCH */ 74 #define ECCEN 0.01671542 /* solar orbit eccentricity */ 75 #define lzero 18.251907 /* lunar mean long at EPOCH */ 76 #define Pzero 192.917585 /* lunar mean long of perigee at EPOCH */ 77 #define Nzero 55.204723 /* lunar mean long of node at EPOCH */ 78 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0) 79 80 static void adj360(double *); 81 static double dtor(double); 82 static double potm(double onday); 83 static double potm_minute(double onday, int olddir); 84 85 void 86 pom(int year, double utcoffset, int *fms, int *nms) 87 { 88 double ffms[MAXMOONS]; 89 double fnms[MAXMOONS]; 90 int i, j; 91 92 fpom(year, utcoffset, ffms, fnms); 93 94 j = 0; 95 for (i = 0; ffms[i] != 0; i++) 96 fms[j++] = round(ffms[i]); 97 fms[i] = -1; 98 for (i = 0; fnms[i] != 0; i++) 99 nms[i] = round(fnms[i]); 100 nms[i] = -1; 101 } 102 103 void 104 fpom(int year, double utcoffset, double *ffms, double *fnms) 105 { 106 time_t tt; 107 struct tm GMT, tmd_today, tmd_tomorrow; 108 double days_today, days_tomorrow, today, tomorrow; 109 int cnt, d; 110 int yeardays; 111 int olddir, newdir; 112 double *pfnms, *pffms, t; 113 114 pfnms = fnms; 115 pffms = ffms; 116 117 /* 118 * We take the phase of the moon one second before and one second 119 * after midnight. 120 */ 121 memset(&tmd_today, 0, sizeof(tmd_today)); 122 tmd_today.tm_year = year - 1900; 123 tmd_today.tm_mon = 0; 124 tmd_today.tm_mday = -1; /* 31 December */ 125 tmd_today.tm_hour = 23; 126 tmd_today.tm_min = 59; 127 tmd_today.tm_sec = 59; 128 memset(&tmd_tomorrow, 0, sizeof(tmd_tomorrow)); 129 tmd_tomorrow.tm_year = year - 1900; 130 tmd_tomorrow.tm_mon = 0; 131 tmd_tomorrow.tm_mday = 0; /* 01 January */ 132 tmd_tomorrow.tm_hour = 0; 133 tmd_tomorrow.tm_min = 0; 134 tmd_tomorrow.tm_sec = 1; 135 136 tt = mktime(&tmd_today); 137 gmtime_r(&tt, &GMT); 138 yeardays = 0; 139 for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt) 140 yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR; 141 days_today = (GMT.tm_yday + 1) + ((GMT.tm_hour + 142 (GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) / 143 FHOURSPERDAY); 144 days_today += yeardays; 145 146 tt = mktime(&tmd_tomorrow); 147 gmtime_r(&tt, &GMT); 148 yeardays = 0; 149 for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt) 150 yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR; 151 days_tomorrow = (GMT.tm_yday + 1) + ((GMT.tm_hour + 152 (GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) / 153 FHOURSPERDAY); 154 days_tomorrow += yeardays; 155 156 today = potm(days_today); /* 30 December 23:59:59 */ 157 tomorrow = potm(days_tomorrow); /* 31 December 00:00:01 */ 158 olddir = today > tomorrow ? -1 : +1; 159 160 yeardays = 1 + (isleap(year) ? DAYSPERLEAPYEAR : DAYSPERYEAR); /* reuse */ 161 for (d = 0; d <= yeardays; d++) { 162 today = potm(days_today); 163 tomorrow = potm(days_tomorrow); 164 newdir = today > tomorrow ? -1 : +1; 165 if (olddir != newdir) { 166 t = potm_minute(days_today - 1, olddir) + 167 utcoffset / FHOURSPERDAY; 168 if (olddir == -1 && newdir == +1) { 169 *pfnms = d - 1 + t; 170 pfnms++; 171 } else if (olddir == +1 && newdir == -1) { 172 *pffms = d - 1 + t; 173 pffms++; 174 } 175 } 176 olddir = newdir; 177 days_today++; 178 days_tomorrow++; 179 } 180 *pffms = -1; 181 *pfnms = -1; 182 } 183 184 static double 185 potm_minute(double onday, int olddir) { 186 double period = FSECSPERDAY / 2.0; 187 double p1, p2; 188 double before, after; 189 int newdir; 190 191 // printf("---> days:%g olddir:%d\n", days, olddir); 192 193 p1 = onday + (period / SECSPERDAY); 194 period /= 2; 195 196 while (period > 30) { /* half a minute */ 197 // printf("period:%g - p1:%g - ", period, p1); 198 p2 = p1 + (2.0 / SECSPERDAY); 199 before = potm(p1); 200 after = potm(p2); 201 // printf("before:%10.10g - after:%10.10g\n", before, after); 202 newdir = before < after ? -1 : +1; 203 if (olddir != newdir) 204 p1 += (period / SECSPERDAY); 205 else 206 p1 -= (period / SECSPERDAY); 207 period /= 2; 208 // printf("newdir:%d - p1:%10.10f - period:%g\n", 209 // newdir, p1, period); 210 } 211 p1 -= floor(p1); 212 //exit(0); 213 return (p1); 214 } 215 216 /* 217 * potm -- 218 * return phase of the moon, as a percentage [0 ... 100] 219 */ 220 static double 221 potm(double onday) 222 { 223 double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime; 224 double A4, lprime, V, ldprime, D, Nm; 225 226 N = 360 * onday / 365.2422; /* sec 42 #3 */ 227 adj360(&N); 228 Msol = N + EPSILONg - RHOg; /* sec 42 #4 */ 229 adj360(&Msol); 230 Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 42 #5 */ 231 LambdaSol = N + Ec + EPSILONg; /* sec 42 #6 */ 232 adj360(&LambdaSol); 233 l = 13.1763966 * onday + lzero; /* sec 61 #4 */ 234 adj360(&l); 235 Mm = l - (0.1114041 * onday) - Pzero; /* sec 61 #5 */ 236 adj360(&Mm); 237 Nm = Nzero - (0.0529539 * onday); /* sec 61 #6 */ 238 adj360(&Nm); 239 Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 61 #7 */ 240 Ac = 0.1858 * sin(dtor(Msol)); /* sec 61 #8 */ 241 A3 = 0.37 * sin(dtor(Msol)); 242 Mmprime = Mm + Ev - Ac - A3; /* sec 61 #9 */ 243 Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 61 #10 */ 244 A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 61 #11 */ 245 lprime = l + Ev + Ec - Ac + A4; /* sec 61 #12 */ 246 V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 61 #13 */ 247 ldprime = lprime + V; /* sec 61 #14 */ 248 D = ldprime - LambdaSol; /* sec 63 #2 */ 249 return(50 * (1 - cos(dtor(D)))); /* sec 63 #3 */ 250 } 251 252 /* 253 * dtor -- 254 * convert degrees to radians 255 */ 256 static double 257 dtor(double deg) 258 { 259 260 return(deg * PI / 180); 261 } 262 263 /* 264 * adj360 -- 265 * adjust value so 0 <= deg <= 360 266 */ 267 static void 268 adj360(double *deg) 269 { 270 271 for (;;) 272 if (*deg < 0) 273 *deg += 360; 274 else if (*deg > 360) 275 *deg -= 360; 276 else 277 break; 278 } 279