bb06482c77
- Remove the 3rd clause of the UC Berkeley copyrighted files. - For the files added copyrighted by me, move the "All rights reserved" to the next line.
277 lines
7.8 KiB
C
277 lines
7.8 KiB
C
/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software posted to USENET.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#if 0
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#ifndef lint
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static const char copyright[] =
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"@(#) Copyright (c) 1989, 1993\n\
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The Regents of the University of California. All rights reserved.\n";
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#endif /* not lint */
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#ifndef lint
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static const char sccsid[] = "@(#)pom.c 8.1 (Berkeley) 5/31/93";
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#endif /* not lint */
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#endif
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Phase of the Moon. Calculates the current phase of the moon.
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* Based on routines from `Practical Astronomy with Your Calculator',
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* by Duffett-Smith. Comments give the section from the book that
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* particular piece of code was adapted from.
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*
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* -- Keith E. Brandt VIII 1984
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <string.h>
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#include <sysexits.h>
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#include <time.h>
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#include <unistd.h>
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#include "calendar.h"
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#ifndef PI
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#define PI 3.14159265358979323846
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#endif
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#define EPOCH 85
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#define EPSILONg 279.611371 /* solar ecliptic long at EPOCH */
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#define RHOg 282.680403 /* solar ecliptic long of perigee at EPOCH */
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#define ECCEN 0.01671542 /* solar orbit eccentricity */
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#define lzero 18.251907 /* lunar mean long at EPOCH */
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#define Pzero 192.917585 /* lunar mean long of perigee at EPOCH */
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#define Nzero 55.204723 /* lunar mean long of node at EPOCH */
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#define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
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static void adj360(double *);
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static double dtor(double);
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static double potm(double onday);
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static double potm_minute(double onday, int olddir);
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void
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pom(int year, double utcoffset, int *fms, int *nms)
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{
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double ffms[MAXMOONS];
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double fnms[MAXMOONS];
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int i, j;
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fpom(year, utcoffset, ffms, fnms);
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j = 0;
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for (i = 0; ffms[i] != 0; i++)
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fms[j++] = round(ffms[i]);
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fms[i] = -1;
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for (i = 0; fnms[i] != 0; i++)
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nms[i] = round(fnms[i]);
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nms[i] = -1;
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}
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void
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fpom(int year, double utcoffset, double *ffms, double *fnms)
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{
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time_t tt;
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struct tm GMT, tmd_today, tmd_tomorrow;
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double days_today, days_tomorrow, today, tomorrow;
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int cnt, d;
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int yeardays;
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int olddir, newdir;
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double *pfnms, *pffms, t;
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pfnms = fnms;
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pffms = ffms;
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/*
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* We take the phase of the moon one second before and one second
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* after midnight.
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*/
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memset(&tmd_today, 0, sizeof(tmd_today));
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tmd_today.tm_year = year - 1900;
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tmd_today.tm_mon = 0;
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tmd_today.tm_mday = -1; /* 31 December */
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tmd_today.tm_hour = 23;
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tmd_today.tm_min = 59;
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tmd_today.tm_sec = 59;
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memset(&tmd_tomorrow, 0, sizeof(tmd_tomorrow));
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tmd_tomorrow.tm_year = year - 1900;
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tmd_tomorrow.tm_mon = 0;
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tmd_tomorrow.tm_mday = 0; /* 01 January */
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tmd_tomorrow.tm_hour = 0;
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tmd_tomorrow.tm_min = 0;
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tmd_tomorrow.tm_sec = 1;
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tt = mktime(&tmd_today);
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gmtime_r(&tt, &GMT);
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yeardays = 0;
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for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt)
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yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR;
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days_today = (GMT.tm_yday + 1) + ((GMT.tm_hour +
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(GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) /
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FHOURSPERDAY);
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days_today += yeardays;
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tt = mktime(&tmd_tomorrow);
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gmtime_r(&tt, &GMT);
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yeardays = 0;
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for (cnt = EPOCH; cnt < GMT.tm_year; ++cnt)
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yeardays += isleap(1900 + cnt) ? DAYSPERLEAPYEAR : DAYSPERYEAR;
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days_tomorrow = (GMT.tm_yday + 1) + ((GMT.tm_hour +
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(GMT.tm_min / FSECSPERMINUTE) + (GMT.tm_sec / FSECSPERHOUR)) /
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FHOURSPERDAY);
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days_tomorrow += yeardays;
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today = potm(days_today); /* 30 December 23:59:59 */
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tomorrow = potm(days_tomorrow); /* 31 December 00:00:01 */
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olddir = today > tomorrow ? -1 : +1;
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yeardays = 1 + isleap(year) ? DAYSPERLEAPYEAR : DAYSPERYEAR; /* reuse */
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for (d = 0; d <= yeardays; d++) {
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today = potm(days_today);
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tomorrow = potm(days_tomorrow);
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newdir = today > tomorrow ? -1 : +1;
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if (olddir != newdir) {
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t = potm_minute(days_today - 1, olddir) +
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utcoffset / FHOURSPERDAY;
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if (olddir == -1 && newdir == +1) {
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*pfnms = d - 1 + t;
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pfnms++;
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} else if (olddir == +1 && newdir == -1) {
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*pffms = d - 1 + t;
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pffms++;
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}
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}
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olddir = newdir;
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days_today++;
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days_tomorrow++;
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}
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*pffms = -1;
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*pfnms = -1;
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}
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static double
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potm_minute(double onday, int olddir) {
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double period = FSECSPERDAY / 2.0;
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double p1, p2;
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double before, after;
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int newdir;
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// printf("---> days:%g olddir:%d\n", days, olddir);
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p1 = onday + (period / SECSPERDAY);
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period /= 2;
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while (period > 30) { /* half a minute */
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// printf("period:%g - p1:%g - ", period, p1);
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p2 = p1 + (2.0 / SECSPERDAY);
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before = potm(p1);
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after = potm(p2);
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// printf("before:%10.10g - after:%10.10g\n", before, after);
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newdir = before < after ? -1 : +1;
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if (olddir != newdir)
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p1 += (period / SECSPERDAY);
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else
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p1 -= (period / SECSPERDAY);
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period /= 2;
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// printf("newdir:%d - p1:%10.10f - period:%g\n",
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// newdir, p1, period);
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}
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p1 -= floor(p1);
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//exit(0);
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return (p1);
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}
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/*
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* potm --
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* return phase of the moon, as a percentage [0 ... 100]
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*/
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static double
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potm(double onday)
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{
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double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime;
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double A4, lprime, V, ldprime, D, Nm;
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N = 360 * onday / 365.2422; /* sec 42 #3 */
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adj360(&N);
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Msol = N + EPSILONg - RHOg; /* sec 42 #4 */
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adj360(&Msol);
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Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 42 #5 */
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LambdaSol = N + Ec + EPSILONg; /* sec 42 #6 */
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adj360(&LambdaSol);
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l = 13.1763966 * onday + lzero; /* sec 61 #4 */
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adj360(&l);
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Mm = l - (0.1114041 * onday) - Pzero; /* sec 61 #5 */
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adj360(&Mm);
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Nm = Nzero - (0.0529539 * onday); /* sec 61 #6 */
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adj360(&Nm);
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Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 61 #7 */
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Ac = 0.1858 * sin(dtor(Msol)); /* sec 61 #8 */
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A3 = 0.37 * sin(dtor(Msol));
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Mmprime = Mm + Ev - Ac - A3; /* sec 61 #9 */
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Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 61 #10 */
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A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 61 #11 */
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lprime = l + Ev + Ec - Ac + A4; /* sec 61 #12 */
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V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 61 #13 */
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ldprime = lprime + V; /* sec 61 #14 */
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D = ldprime - LambdaSol; /* sec 63 #2 */
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return(50 * (1 - cos(dtor(D)))); /* sec 63 #3 */
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}
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/*
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* dtor --
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* convert degrees to radians
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*/
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static double
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dtor(double deg)
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{
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return(deg * PI / 180);
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}
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/*
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* adj360 --
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* adjust value so 0 <= deg <= 360
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*/
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static void
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adj360(double *deg)
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{
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for (;;)
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if (*deg < 0)
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*deg += 360;
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else if (*deg > 360)
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*deg -= 360;
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else
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break;
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}
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