-
Notifications
You must be signed in to change notification settings - Fork 57
/
Copy pathanalemma.html
203 lines (170 loc) · 4.61 KB
/
analemma.html
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
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
<html>
<head>
<title>
ANALEMMA - Evaluating the Equation of Time
</title>
</head>
<body bgcolor="#EEEEEE" link="#CC0000" alink="#FF3300" vlink="#000055">
<h1 align = "center">
ANALEMMA <br> Evaluating the Equation of Time
</h1>
<hr>
<p>
<b>ANALEMMA</b>
is a MATLAB program which evaluates the equation of time.
</p>
<p>
The program computes and plots the equation of time, the declination,
and an analemma curve for
various orbital parameters. The analemma is the curve traced by the position
of the sun, measured at clock noon, over a year.
</p>
<h3 align = "center">
Usage:
</h3>
<p>
<blockquote>
<b>analemma</b> ( <i>ecc</i>, <i>lon</i>, <i>obliq</i> )
</blockquote>
where the optional input parameters are:
<ul>
<li>
<i>ecc</i>, the eccentricity;
</li>
<li>
<i>lon</i>, the perihelion longitude in degrees;
</li>
<li>
<i>obliq</i>, the axial obliquity in degrees;
</li>
</ul>
</p>
<p>
The program with no options uses the following default values:
<ul>
<li>
eccentricity = 0.01671;
</li>
<li>
longitude of perihelion = 1.347 radians = 77.18 degrees;
</li>
<li>
axial obliquity = 0.4091 radians = 23.44 degrees;
</li>
</ul>
</p>
<h3 align = "center">
Licensing:
</h3>
<p>
The computer code and data files described and made available on this web page
are distributed under
<a href = "../../txt/gnu_lgpl.txt">the GNU LGPL license.</a>
</p>
<h3 align = "center">
Languages:
</h3>
<p>
<b>ANALEMMA</b> is available in
<a href = "../../c_src/analemma/analemma.html">a C version</a> and
<a href = "../../cpp_src/analemma/analemma.html">a C++ version</a> and
<a href = "../../f77_src/analemma/analemma.html">a FORTRAN77 version</a> and
<a href = "../../f_src/analemma/analemma.html">a FORTRAN90 version</a> and
<a href = "../../m_src/analemma/analemma.html">a MATLAB version</a>.
</p>
<h3 align = "center">
Related Data and Programs:
</h3>
<p>
<a href = "../../cpp_src/calendar_rd/calendar_rd.html">
CALENDAR_RD</a>,
a C++ program which
computes the representation of a given date in a
number of calendrical systems,
by Edward Reingold, Nachum Dershowitz.
</p>
<p>
<a href = "../../m_src/calpak/calpak.html">
CALPAK</a>,
a MATLAB library which
makes various calendar calculations;
</p>
<p>
<a href = "../../datasets/dates/dates.html">
DATES</a>,
a dataset directory which
contains lists of dates in various calendar systems.
</p>
<p>
<a href = "../../m_src/weekday/weekday.html">
WEEKDAY</a>,
a MATLAB library which
determines the day of the week corresponding to a given date,
such as 14 October 1066, Julian calendar, ... which was a Saturday.
</p>
<h3 align = "center">
Reference:
</h3>
<p>
<ol>
<li>
Brian Tung,<br>
Figure Eight in the Sky, a new perspective on an old fascination,<br>
Astronomical Games, August 2002,<br>
http://www.astronomycorner.net/games/analemma.html.
</li>
</ol>
</p>
<h3 align = "center">
Source Code:
</h3>
<p>
<ul>
<li>
<a href = "analemma.m">analemma.m</a>, the source code.
</li>
</ul>
</p>
<h3 align = "center">
Examples and Tests:
</h3>
<p>
<ul>
<li>
<a href = "analemma.png">analemma.png</a>,
the PNG file of the analemma.
</li>
<li>
<a href = "declination.png">declination.png</a>,
the PNG file of the declination.
</li>
<li>
<a href = "eot.png">eot.png</a>,
the PNG file of the equation of time.
</li>
</ul>
<h3 align = "center">
List of Routines:
</h3>
<p>
<ul>
<li>
<b>MAIN</b> is the main program for ANALEMMA.
</li>
<li>
<b>TIMESTAMP</b> prints the current YMDHMS date as a time stamp.
</li>
</ul>
</p>
<p>
You can go up one level to <a href = "../m_src.html">
the MATLAB source codes</a>.
</p>
<hr>
<i>
Last revised on 05 January 2013.
</i>
<!-- John Burkardt -->
</body>
<!-- Initial HTML skeleton created by HTMLINDEX. -->
</html>