source: branches/FACT++_lidctrl_usb/erfa/src/c2ibpn.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: 6.0 KB
Line 
1#include "erfa.h"
2
3void eraC2ibpn(double date1, double date2, double rbpn[3][3],
4 double rc2i[3][3])
5/*
6** - - - - - - - - - -
7** e r a C 2 i b p n
8** - - - - - - - - - -
9**
10** Form the celestial-to-intermediate matrix for a given date given
11** the bias-precession-nutation matrix. IAU 2000.
12**
13** Given:
14** date1,date2 double TT as a 2-part Julian Date (Note 1)
15** rbpn double[3][3] celestial-to-true matrix (Note 2)
16**
17** Returned:
18** rc2i double[3][3] celestial-to-intermediate matrix (Note 3)
19**
20** Notes:
21**
22** 1) The TT date date1+date2 is a Julian Date, apportioned in any
23** convenient way between the two arguments. For example,
24** JD(TT)=2450123.7 could be expressed in any of these ways,
25** among others:
26**
27** date1 date2
28**
29** 2450123.7 0.0 (JD method)
30** 2451545.0 -1421.3 (J2000 method)
31** 2400000.5 50123.2 (MJD method)
32** 2450123.5 0.2 (date & time method)
33**
34** The JD method is the most natural and convenient to use in
35** cases where the loss of several decimal digits of resolution
36** is acceptable. The J2000 method is best matched to the way
37** the argument is handled internally and will deliver the
38** optimum resolution. The MJD method and the date & time methods
39** are both good compromises between resolution and convenience.
40**
41** 2) The matrix rbpn transforms vectors from GCRS to true equator (and
42** CIO or equinox) of date. Only the CIP (bottom row) is used.
43**
44** 3) The matrix rc2i is the first stage in the transformation from
45** celestial to terrestrial coordinates:
46**
47** [TRS] = RPOM * R_3(ERA) * rc2i * [CRS]
48**
49** = RC2T * [CRS]
50**
51** where [CRS] is a vector in the Geocentric Celestial Reference
52** System and [TRS] is a vector in the International Terrestrial
53** Reference System (see IERS Conventions 2003), ERA is the Earth
54** Rotation Angle and RPOM is the polar motion matrix.
55**
56** 4) Although its name does not include "00", This function is in fact
57** specific to the IAU 2000 models.
58**
59** Called:
60** eraBpn2xy extract CIP X,Y coordinates from NPB matrix
61** eraC2ixy celestial-to-intermediate matrix, given X,Y
62**
63** References:
64** "Expressions for the Celestial Intermediate Pole and Celestial
65** Ephemeris Origin consistent with the IAU 2000A precession-
66** nutation model", Astron.Astrophys. 400, 1145-1154 (2003)
67**
68** n.b. The celestial ephemeris origin (CEO) was renamed "celestial
69** intermediate origin" (CIO) by IAU 2006 Resolution 2.
70**
71** McCarthy, D. D., Petit, G. (eds.), IERS Conventions (2003),
72** IERS Technical Note No. 32, BKG (2004)
73**
74** Copyright (C) 2013-2016, NumFOCUS Foundation.
75** Derived, with permission, from the SOFA library. See notes at end of file.
76*/
77{
78 double x, y;
79
80
81/* Extract the X,Y coordinates. */
82 eraBpn2xy(rbpn, &x, &y);
83
84/* Form the celestial-to-intermediate matrix (n.b. IAU 2000 specific). */
85 eraC2ixy(date1, date2, x, y, rc2i);
86
87 return;
88
89}
90/*----------------------------------------------------------------------
91**
92**
93** Copyright (C) 2013-2016, NumFOCUS Foundation.
94** All rights reserved.
95**
96** This library is derived, with permission, from the International
97** Astronomical Union's "Standards of Fundamental Astronomy" library,
98** available from http://www.iausofa.org.
99**
100** The ERFA version is intended to retain identical functionality to
101** the SOFA library, but made distinct through different function and
102** file names, as set out in the SOFA license conditions. The SOFA
103** original has a role as a reference standard for the IAU and IERS,
104** and consequently redistribution is permitted only in its unaltered
105** state. The ERFA version is not subject to this restriction and
106** therefore can be included in distributions which do not support the
107** concept of "read only" software.
108**
109** Although the intent is to replicate the SOFA API (other than
110** replacement of prefix names) and results (with the exception of
111** bugs; any that are discovered will be fixed), SOFA is not
112** responsible for any errors found in this version of the library.
113**
114** If you wish to acknowledge the SOFA heritage, please acknowledge
115** that you are using a library derived from SOFA, rather than SOFA
116** itself.
117**
118**
119** TERMS AND CONDITIONS
120**
121** Redistribution and use in source and binary forms, with or without
122** modification, are permitted provided that the following conditions
123** are met:
124**
125** 1 Redistributions of source code must retain the above copyright
126** notice, this list of conditions and the following disclaimer.
127**
128** 2 Redistributions in binary form must reproduce the above copyright
129** notice, this list of conditions and the following disclaimer in
130** the documentation and/or other materials provided with the
131** distribution.
132**
133** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
134** the International Astronomical Union nor the names of its
135** contributors may be used to endorse or promote products derived
136** from this software without specific prior written permission.
137**
138** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
139** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
140** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
141** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
142** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
143** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
144** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
145** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
146** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
147** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
148** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
149** POSSIBILITY OF SUCH DAMAGE.
150**
151*/
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