source: trunk/FACT++/erfa/src/nutm80.c@ 18350

Last change on this file since 18350 was 18348, checked in by tbretz, 9 years ago
File size: 4.9 KB
Line 
1#include "erfa.h"
2
3void eraNutm80(double date1, double date2, double rmatn[3][3])
4/*
5** - - - - - - - - - -
6** e r a N u t m 8 0
7** - - - - - - - - - -
8**
9** Form the matrix of nutation for a given date, IAU 1980 model.
10**
11** Given:
12** date1,date2 double TDB 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),
39** where the p-vector V(true) is with respect to the true
40** equatorial triad of date and the p-vector V(mean) is with
41** respect to the mean equatorial triad of date.
42**
43** Called:
44** eraNut80 nutation, IAU 1980
45** eraObl80 mean obliquity, IAU 1980
46** eraNumat form nutation matrix
47**
48** Copyright (C) 2013-2015, NumFOCUS Foundation.
49** Derived, with permission, from the SOFA library. See notes at end of file.
50*/
51{
52 double dpsi, deps, epsa;
53
54/* Nutation components and mean obliquity. */
55 eraNut80(date1, date2, &dpsi, &deps);
56 epsa = eraObl80(date1, date2);
57
58/* Build the rotation matrix. */
59 eraNumat(epsa, dpsi, deps, rmatn);
60
61 return;
62
63}
64/*----------------------------------------------------------------------
65**
66**
67** Copyright (C) 2013-2015, NumFOCUS Foundation.
68** All rights reserved.
69**
70** This library is derived, with permission, from the International
71** Astronomical Union's "Standards of Fundamental Astronomy" library,
72** available from http://www.iausofa.org.
73**
74** The ERFA version is intended to retain identical functionality to
75** the SOFA library, but made distinct through different function and
76** file names, as set out in the SOFA license conditions. The SOFA
77** original has a role as a reference standard for the IAU and IERS,
78** and consequently redistribution is permitted only in its unaltered
79** state. The ERFA version is not subject to this restriction and
80** therefore can be included in distributions which do not support the
81** concept of "read only" software.
82**
83** Although the intent is to replicate the SOFA API (other than
84** replacement of prefix names) and results (with the exception of
85** bugs; any that are discovered will be fixed), SOFA is not
86** responsible for any errors found in this version of the library.
87**
88** If you wish to acknowledge the SOFA heritage, please acknowledge
89** that you are using a library derived from SOFA, rather than SOFA
90** itself.
91**
92**
93** TERMS AND CONDITIONS
94**
95** Redistribution and use in source and binary forms, with or without
96** modification, are permitted provided that the following conditions
97** are met:
98**
99** 1 Redistributions of source code must retain the above copyright
100** notice, this list of conditions and the following disclaimer.
101**
102** 2 Redistributions in binary form must reproduce the above copyright
103** notice, this list of conditions and the following disclaimer in
104** the documentation and/or other materials provided with the
105** distribution.
106**
107** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
108** the International Astronomical Union nor the names of its
109** contributors may be used to endorse or promote products derived
110** from this software without specific prior written permission.
111**
112** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
113** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
114** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
115** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
116** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
117** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
118** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
119** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
120** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
121** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
122** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
123** POSSIBILITY OF SUCH DAMAGE.
124**
125*/
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