179 lines
5.5 KiB
C
179 lines
5.5 KiB
C
/*
|
|
* Copyright (c) 1989, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software posted to USENET.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char copyright[] =
|
|
"@(#) Copyright (c) 1989, 1993\n\
|
|
The Regents of the University of California. All rights reserved.\n";
|
|
#endif /* not lint */
|
|
|
|
#ifndef lint
|
|
static char sccsid[] = "@(#)pom.c 8.1 (Berkeley) 5/31/93";
|
|
#endif /* not lint */
|
|
|
|
/*
|
|
* Phase of the Moon. Calculates the current phase of the moon.
|
|
* Based on routines from `Practical Astronomy with Your Calculator',
|
|
* by Duffett-Smith. Comments give the section from the book that
|
|
* particular piece of code was adapted from.
|
|
*
|
|
* -- Keith E. Brandt VIII 1984
|
|
*
|
|
*/
|
|
|
|
#include <sys/time.h>
|
|
#include <stdio.h>
|
|
#include <math.h>
|
|
|
|
#define PI 3.141592654
|
|
#define EPOCH 85
|
|
#define EPSILONg 279.611371 /* solar ecliptic long at EPOCH */
|
|
#define RHOg 282.680403 /* solar ecliptic long of perigee at EPOCH */
|
|
#define ECCEN 0.01671542 /* solar orbit eccentricity */
|
|
#define lzero 18.251907 /* lunar mean long at EPOCH */
|
|
#define Pzero 192.917585 /* lunar mean long of perigee at EPOCH */
|
|
#define Nzero 55.204723 /* lunar mean long of node at EPOCH */
|
|
#define isleap(y) (((y) % 4) == 0 && ((y) % 100) != 0 || ((y) % 400) == 0)
|
|
|
|
double dtor(), potm(), adj360();
|
|
|
|
main()
|
|
{
|
|
extern int errno;
|
|
struct timeval tp;
|
|
struct timezone tzp;
|
|
struct tm *GMT, *gmtime();
|
|
double days, today, tomorrow;
|
|
int cnt;
|
|
char *strerror();
|
|
|
|
if (gettimeofday(&tp,&tzp)) {
|
|
(void)fprintf(stderr, "pom: %s\n", strerror(errno));
|
|
exit(1);
|
|
}
|
|
GMT = gmtime(&tp.tv_sec);
|
|
days = (GMT->tm_yday + 1) + ((GMT->tm_hour +
|
|
(GMT->tm_min / 60.0) + (GMT->tm_sec / 3600.0)) / 24.0);
|
|
for (cnt = EPOCH; cnt < GMT->tm_year; ++cnt)
|
|
days += isleap(cnt) ? 366 : 365;
|
|
today = potm(days) + .5;
|
|
(void)printf("The Moon is ");
|
|
if ((int)today == 100)
|
|
(void)printf("Full\n");
|
|
else if (!(int)today)
|
|
(void)printf("New\n");
|
|
else {
|
|
tomorrow = potm(days + 1);
|
|
if ((int)today == 50)
|
|
(void)printf("%s\n", tomorrow > today ?
|
|
"at the First Quarter" : "at the Last Quarter");
|
|
else {
|
|
(void)printf("%s ", tomorrow > today ?
|
|
"Waxing" : "Waning");
|
|
if (today > 50)
|
|
(void)printf("Gibbous (%1.0f%% of Full)\n",
|
|
today);
|
|
else if (today < 50)
|
|
(void)printf("Crescent (%1.0f%% of Full)\n",
|
|
today);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* potm --
|
|
* return phase of the moon
|
|
*/
|
|
double
|
|
potm(days)
|
|
double days;
|
|
{
|
|
double N, Msol, Ec, LambdaSol, l, Mm, Ev, Ac, A3, Mmprime;
|
|
double A4, lprime, V, ldprime, D, Nm;
|
|
|
|
N = 360 * days / 365.2422; /* sec 42 #3 */
|
|
adj360(&N);
|
|
Msol = N + EPSILONg - RHOg; /* sec 42 #4 */
|
|
adj360(&Msol);
|
|
Ec = 360 / PI * ECCEN * sin(dtor(Msol)); /* sec 42 #5 */
|
|
LambdaSol = N + Ec + EPSILONg; /* sec 42 #6 */
|
|
adj360(&LambdaSol);
|
|
l = 13.1763966 * days + lzero; /* sec 61 #4 */
|
|
adj360(&l);
|
|
Mm = l - (0.1114041 * days) - Pzero; /* sec 61 #5 */
|
|
adj360(&Mm);
|
|
Nm = Nzero - (0.0529539 * days); /* sec 61 #6 */
|
|
adj360(&Nm);
|
|
Ev = 1.2739 * sin(dtor(2*(l - LambdaSol) - Mm)); /* sec 61 #7 */
|
|
Ac = 0.1858 * sin(dtor(Msol)); /* sec 61 #8 */
|
|
A3 = 0.37 * sin(dtor(Msol));
|
|
Mmprime = Mm + Ev - Ac - A3; /* sec 61 #9 */
|
|
Ec = 6.2886 * sin(dtor(Mmprime)); /* sec 61 #10 */
|
|
A4 = 0.214 * sin(dtor(2 * Mmprime)); /* sec 61 #11 */
|
|
lprime = l + Ev + Ec - Ac + A4; /* sec 61 #12 */
|
|
V = 0.6583 * sin(dtor(2 * (lprime - LambdaSol))); /* sec 61 #13 */
|
|
ldprime = lprime + V; /* sec 61 #14 */
|
|
D = ldprime - LambdaSol; /* sec 63 #2 */
|
|
return(50 * (1 - cos(dtor(D)))); /* sec 63 #3 */
|
|
}
|
|
|
|
/*
|
|
* dtor --
|
|
* convert degrees to radians
|
|
*/
|
|
double
|
|
dtor(deg)
|
|
double deg;
|
|
{
|
|
return(deg * PI / 180);
|
|
}
|
|
|
|
/*
|
|
* adj360 --
|
|
* adjust value so 0 <= deg <= 360
|
|
*/
|
|
double
|
|
adj360(deg)
|
|
double *deg;
|
|
{
|
|
for (;;)
|
|
if (*deg < 0)
|
|
*deg += 360;
|
|
else if (*deg > 360)
|
|
*deg -= 360;
|
|
else
|
|
break;
|
|
}
|