1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
|
/* $NetBSD: pom.c,v 1.5 1995/06/07 16:30:46 cgd Exp $ */
/*
* 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
#if 0
static char sccsid[] = "@(#)pom.c 8.1 (Berkeley) 5/31/93";
#else
static char rcsid[] = "$NetBSD: pom.c,v 1.5 1995/06/07 16:30:46 cgd Exp $";
#endif
#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 <string.h>
#include <tzfile.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 */
double dtor(), potm(), adj360();
main()
{
extern int errno;
struct timeval tp;
struct timezone tzp;
struct tm *GMT, *gmtime();
time_t tmpt;
double days, today, tomorrow;
int cnt;
if (gettimeofday(&tp,&tzp)) {
(void)fprintf(stderr, "pom: %s\n", strerror(errno));
exit(1);
}
tmpt = tp.tv_sec;
GMT = gmtime(&tmpt);
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);
}
}
exit(0);
}
/*
* 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;
}
|
