source: branches/FACT++_lidctrl_usb/erfa/src/num06a.c@ 19875

Last change on this file since 19875 was 18711, checked in by tbretz, 10 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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