source: branches/FACT++_lidctrl_usb/erfa/src/num06a.c@ 18728

Last change on this file since 18728 was 18711, checked in by tbretz, 9 years ago
Updated to ERFA 1.3.0 (no relevant code change except the leap second at the beginning of 2017)
File size: 5.1 KB
Line 
1#include "erfa.h"
2
3void eraNum06a(double date1, double date2, double rmatn[3][3])
4/*
5** - - - - - - - - - -
6** e r a N u m 0 6 a
7** - - - - - - - - - -
8**
9** Form the matrix of nutation for a given date, IAU 2006/2000A model.
10**
11** Given:
12** date1,date2 double TT as a 2-part Julian Date (Note 1)
13**
14** Returned:
15** rmatn double[3][3] nutation matrix
16**
17** Notes:
18**
19** 1) The TT date date1+date2 is a Julian Date, apportioned in any
20** convenient way between the two arguments. For example,
21** JD(TT)=2450123.7 could be expressed in any of these ways,
22** among others:
23**
24** date1 date2
25**
26** 2450123.7 0.0 (JD method)
27** 2451545.0 -1421.3 (J2000 method)
28** 2400000.5 50123.2 (MJD method)
29** 2450123.5 0.2 (date & time method)
30**
31** The JD method is the most natural and convenient to use in
32** cases where the loss of several decimal digits of resolution
33** is acceptable. The J2000 method is best matched to the way
34** the argument is handled internally and will deliver the
35** optimum resolution. The MJD method and the date & time methods
36** are both good compromises between resolution and convenience.
37**
38** 2) The matrix operates in the sense V(true) = rmatn * V(mean), where
39** the p-vector V(true) is with respect to the true equatorial triad
40** of date and the p-vector V(mean) is with respect to the mean
41** equatorial triad of date.
42**
43** Called:
44** eraObl06 mean obliquity, IAU 2006
45** eraNut06a nutation, IAU 2006/2000A
46** eraNumat form nutation matrix
47**
48** Reference:
49**
50** Explanatory Supplement to the Astronomical Almanac,
51** P. Kenneth Seidelmann (ed), University Science Books (1992),
52** Section 3.222-3 (p114).
53**
54** Copyright (C) 2013-2016, NumFOCUS Foundation.
55** Derived, with permission, from the SOFA library. See notes at end of file.
56*/
57{
58 double eps, dp, de;
59
60
61/* Mean obliquity. */
62 eps = eraObl06(date1, date2);
63
64/* Nutation components. */
65 eraNut06a(date1, date2, &dp, &de);
66
67/* Nutation matrix. */
68 eraNumat(eps, dp, de, rmatn);
69
70 return;
71
72}
73/*----------------------------------------------------------------------
74**
75**
76** Copyright (C) 2013-2016, NumFOCUS Foundation.
77** All rights reserved.
78**
79** This library is derived, with permission, from the International
80** Astronomical Union's "Standards of Fundamental Astronomy" library,
81** available from http://www.iausofa.org.
82**
83** The ERFA version is intended to retain identical functionality to
84** the SOFA library, but made distinct through different function and
85** file names, as set out in the SOFA license conditions. The SOFA
86** original has a role as a reference standard for the IAU and IERS,
87** and consequently redistribution is permitted only in its unaltered
88** state. The ERFA version is not subject to this restriction and
89** therefore can be included in distributions which do not support the
90** concept of "read only" software.
91**
92** Although the intent is to replicate the SOFA API (other than
93** replacement of prefix names) and results (with the exception of
94** bugs; any that are discovered will be fixed), SOFA is not
95** responsible for any errors found in this version of the library.
96**
97** If you wish to acknowledge the SOFA heritage, please acknowledge
98** that you are using a library derived from SOFA, rather than SOFA
99** itself.
100**
101**
102** TERMS AND CONDITIONS
103**
104** Redistribution and use in source and binary forms, with or without
105** modification, are permitted provided that the following conditions
106** are met:
107**
108** 1 Redistributions of source code must retain the above copyright
109** notice, this list of conditions and the following disclaimer.
110**
111** 2 Redistributions in binary form must reproduce the above copyright
112** notice, this list of conditions and the following disclaimer in
113** the documentation and/or other materials provided with the
114** distribution.
115**
116** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
117** the International Astronomical Union nor the names of its
118** contributors may be used to endorse or promote products derived
119** from this software without specific prior written permission.
120**
121** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
122** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
123** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
124** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
125** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
126** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
127** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
128** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
129** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
130** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
131** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
132** POSSIBILITY OF SUCH DAMAGE.
133**
134*/
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