source: trunk/FACT++/sofa/src/nutm80.c@ 18346

Last change on this file since 18346 was 18346, checked in by tbretz, 9 years ago
File size: 6.3 KB
Line 
1#include "sofa.h"
2
3void iauNutm80(double date1, double date2, double rmatn[3][3])
4/*
5** - - - - - - - - - -
6** i a u N u t m 8 0
7** - - - - - - - - - -
8**
9** Form the matrix of nutation for a given date, IAU 1980 model.
10**
11** This function is part of the International Astronomical Union's
12** SOFA (Standards Of Fundamental Astronomy) software collection.
13**
14** Status: support function.
15**
16** Given:
17** date1,date2 double TDB date (Note 1)
18**
19** Returned:
20** rmatn double[3][3] nutation matrix
21**
22** Notes:
23**
24** 1) The TT date date1+date2 is a Julian Date, apportioned in any
25** convenient way between the two arguments. For example,
26** JD(TT)=2450123.7 could be expressed in any of these ways,
27** among others:
28**
29** date1 date2
30**
31** 2450123.7 0.0 (JD method)
32** 2451545.0 -1421.3 (J2000 method)
33** 2400000.5 50123.2 (MJD method)
34** 2450123.5 0.2 (date & time method)
35**
36** The JD method is the most natural and convenient to use in
37** cases where the loss of several decimal digits of resolution
38** is acceptable. The J2000 method is best matched to the way
39** the argument is handled internally and will deliver the
40** optimum resolution. The MJD method and the date & time methods
41** are both good compromises between resolution and convenience.
42**
43** 2) The matrix operates in the sense V(true) = rmatn * V(mean),
44** where the p-vector V(true) is with respect to the true
45** equatorial triad of date and the p-vector V(mean) is with
46** respect to the mean equatorial triad of date.
47**
48** Called:
49** iauNut80 nutation, IAU 1980
50** iauObl80 mean obliquity, IAU 1980
51** iauNumat form nutation matrix
52**
53** This revision: 2013 June 18
54**
55** SOFA release 2015-02-09
56**
57** Copyright (C) 2015 IAU SOFA Board. See notes at end.
58*/
59{
60 double dpsi, deps, epsa;
61
62/* Nutation components and mean obliquity. */
63 iauNut80(date1, date2, &dpsi, &deps);
64 epsa = iauObl80(date1, date2);
65
66/* Build the rotation matrix. */
67 iauNumat(epsa, dpsi, deps, rmatn);
68
69 return;
70
71/*----------------------------------------------------------------------
72**
73** Copyright (C) 2015
74** Standards Of Fundamental Astronomy Board
75** of the International Astronomical Union.
76**
77** =====================
78** SOFA Software License
79** =====================
80**
81** NOTICE TO USER:
82**
83** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
84** CONDITIONS WHICH APPLY TO ITS USE.
85**
86** 1. The Software is owned by the IAU SOFA Board ("SOFA").
87**
88** 2. Permission is granted to anyone to use the SOFA software for any
89** purpose, including commercial applications, free of charge and
90** without payment of royalties, subject to the conditions and
91** restrictions listed below.
92**
93** 3. You (the user) may copy and distribute SOFA source code to others,
94** and use and adapt its code and algorithms in your own software,
95** on a world-wide, royalty-free basis. That portion of your
96** distribution that does not consist of intact and unchanged copies
97** of SOFA source code files is a "derived work" that must comply
98** with the following requirements:
99**
100** a) Your work shall be marked or carry a statement that it
101** (i) uses routines and computations derived by you from
102** software provided by SOFA under license to you; and
103** (ii) does not itself constitute software provided by and/or
104** endorsed by SOFA.
105**
106** b) The source code of your derived work must contain descriptions
107** of how the derived work is based upon, contains and/or differs
108** from the original SOFA software.
109**
110** c) The names of all routines in your derived work shall not
111** include the prefix "iau" or "sofa" or trivial modifications
112** thereof such as changes of case.
113**
114** d) The origin of the SOFA components of your derived work must
115** not be misrepresented; you must not claim that you wrote the
116** original software, nor file a patent application for SOFA
117** software or algorithms embedded in the SOFA software.
118**
119** e) These requirements must be reproduced intact in any source
120** distribution and shall apply to anyone to whom you have
121** granted a further right to modify the source code of your
122** derived work.
123**
124** Note that, as originally distributed, the SOFA software is
125** intended to be a definitive implementation of the IAU standards,
126** and consequently third-party modifications are discouraged. All
127** variations, no matter how minor, must be explicitly marked as
128** such, as explained above.
129**
130** 4. You shall not cause the SOFA software to be brought into
131** disrepute, either by misuse, or use for inappropriate tasks, or
132** by inappropriate modification.
133**
134** 5. The SOFA software is provided "as is" and SOFA makes no warranty
135** as to its use or performance. SOFA does not and cannot warrant
136** the performance or results which the user may obtain by using the
137** SOFA software. SOFA makes no warranties, express or implied, as
138** to non-infringement of third party rights, merchantability, or
139** fitness for any particular purpose. In no event will SOFA be
140** liable to the user for any consequential, incidental, or special
141** damages, including any lost profits or lost savings, even if a
142** SOFA representative has been advised of such damages, or for any
143** claim by any third party.
144**
145** 6. The provision of any version of the SOFA software under the terms
146** and conditions specified herein does not imply that future
147** versions will also be made available under the same terms and
148** conditions.
149*
150** In any published work or commercial product which uses the SOFA
151** software directly, acknowledgement (see www.iausofa.org) is
152** appreciated.
153**
154** Correspondence concerning SOFA software should be addressed as
155** follows:
156**
157** By email: sofa@ukho.gov.uk
158** By post: IAU SOFA Center
159** HM Nautical Almanac Office
160** UK Hydrographic Office
161** Admiralty Way, Taunton
162** Somerset, TA1 2DN
163** United Kingdom
164**
165**--------------------------------------------------------------------*/
166}
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