source: trunk/FACT++/erfa/src/fk5hip.c@ 18403

Last change on this file since 18403 was 18348, checked in by tbretz, 9 years ago
File size: 4.6 KB
Line 
1#include "erfa.h"
2
3void eraFk5hip(double r5h[3][3], double s5h[3])
4/*
5** - - - - - - - - - -
6** e r a F k 5 h i p
7** - - - - - - - - - -
8**
9** FK5 to Hipparcos rotation and spin.
10**
11** Returned:
12** r5h double[3][3] r-matrix: FK5 rotation wrt Hipparcos (Note 2)
13** s5h double[3] r-vector: FK5 spin wrt Hipparcos (Note 3)
14**
15** Notes:
16**
17** 1) This function models the FK5 to Hipparcos transformation as a
18** pure rotation and spin; zonal errors in the FK5 catalogue are
19** not taken into account.
20**
21** 2) The r-matrix r5h operates in the sense:
22**
23** P_Hipparcos = r5h x P_FK5
24**
25** where P_FK5 is a p-vector in the FK5 frame, and P_Hipparcos is
26** the equivalent Hipparcos p-vector.
27**
28** 3) The r-vector s5h represents the time derivative of the FK5 to
29** Hipparcos rotation. The units are radians per year (Julian,
30** TDB).
31**
32** Called:
33** eraRv2m r-vector to r-matrix
34**
35** Reference:
36**
37** F.Mignard & M.Froeschle, Astron. Astrophys. 354, 732-739 (2000).
38**
39** Copyright (C) 2013-2015, NumFOCUS Foundation.
40** Derived, with permission, from the SOFA library. See notes at end of file.
41*/
42{
43 double v[3];
44
45/* FK5 wrt Hipparcos orientation and spin (radians, radians/year) */
46 double epx, epy, epz;
47 double omx, omy, omz;
48
49 epx = -19.9e-3 * ERFA_DAS2R;
50 epy = -9.1e-3 * ERFA_DAS2R;
51 epz = 22.9e-3 * ERFA_DAS2R;
52
53 omx = -0.30e-3 * ERFA_DAS2R;
54 omy = 0.60e-3 * ERFA_DAS2R;
55 omz = 0.70e-3 * ERFA_DAS2R;
56
57/* FK5 to Hipparcos orientation expressed as an r-vector. */
58 v[0] = epx;
59 v[1] = epy;
60 v[2] = epz;
61
62/* Re-express as an r-matrix. */
63 eraRv2m(v, r5h);
64
65/* Hipparcos wrt FK5 spin expressed as an r-vector. */
66 s5h[0] = omx;
67 s5h[1] = omy;
68 s5h[2] = omz;
69
70 return;
71
72}
73/*----------------------------------------------------------------------
74**
75**
76** Copyright (C) 2013-2015, 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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