source: trunk/FACT++/sofa/src/atciqz.c@ 18365

Last change on this file since 18365 was 18346, checked in by tbretz, 10 years ago
File size: 7.5 KB
Line 
1#include "sofa.h"
2
3void iauAtciqz(double rc, double dc, iauASTROM *astrom,
4 double *ri, double *di)
5/*
6** - - - - - - - - - -
7** i a u A t c i q z
8** - - - - - - - - - -
9**
10** Quick ICRS to CIRS transformation, given precomputed star-
11** independent astrometry parameters, and assuming zero parallax and
12** proper motion.
13**
14** Use of this function is appropriate when efficiency is important and
15** where many star positions are to be transformed for one date. The
16** star-independent parameters can be obtained by calling one of the
17** functions iauApci[13], iauApcg[13], iauApco[13] or iauApcs[13].
18**
19** The corresponding function for the case of non-zero parallax and
20** proper motion is iauAtciq.
21**
22** This function is part of the International Astronomical Union's
23** SOFA (Standards of Fundamental Astronomy) software collection.
24**
25** Status: support function.
26**
27** Given:
28** rc,dc double ICRS astrometric RA,Dec (radians)
29** astrom iauASTROM* star-independent astrometry parameters:
30** pmt double PM time interval (SSB, Julian years)
31** eb double[3] SSB to observer (vector, au)
32** eh double[3] Sun to observer (unit vector)
33** em double distance from Sun to observer (au)
34** v double[3] barycentric observer velocity (vector, c)
35** bm1 double sqrt(1-|v|^2): reciprocal of Lorenz factor
36** bpn double[3][3] bias-precession-nutation matrix
37** along double longitude + s' (radians)
38** xpl double polar motion xp wrt local meridian (radians)
39** ypl double polar motion yp wrt local meridian (radians)
40** sphi double sine of geodetic latitude
41** cphi double cosine of geodetic latitude
42** diurab double magnitude of diurnal aberration vector
43** eral double "local" Earth rotation angle (radians)
44** refa double refraction constant A (radians)
45** refb double refraction constant B (radians)
46**
47** Returned:
48** ri,di double CIRS RA,Dec (radians)
49**
50** Note:
51**
52** All the vectors are with respect to BCRS axes.
53**
54** References:
55**
56** Urban, S. & Seidelmann, P. K. (eds), Explanatory Supplement to
57** the Astronomical Almanac, 3rd ed., University Science Books
58** (2013).
59**
60** Klioner, Sergei A., "A practical relativistic model for micro-
61** arcsecond astrometry in space", Astr. J. 125, 1580-1597 (2003).
62**
63** Called:
64** iauS2c spherical coordinates to unit vector
65** iauLdsun light deflection due to Sun
66** iauAb stellar aberration
67** iauRxp product of r-matrix and p-vector
68** iauC2s p-vector to spherical
69** iauAnp normalize angle into range +/- pi
70**
71** This revision: 2013 October 9
72**
73** SOFA release 2015-02-09
74**
75** Copyright (C) 2015 IAU SOFA Board. See notes at end.
76*/
77{
78 double pco[3], pnat[3], ppr[3], pi[3], w;
79
80/* BCRS coordinate direction (unit vector). */
81 iauS2c(rc, dc, pco);
82
83/* Light deflection by the Sun, giving BCRS natural direction. */
84 iauLdsun(pco, astrom->eh, astrom->em, pnat);
85
86/* Aberration, giving GCRS proper direction. */
87 iauAb(pnat, astrom->v, astrom->em, astrom->bm1, ppr);
88
89/* Bias-precession-nutation, giving CIRS proper direction. */
90 iauRxp(astrom->bpn, ppr, pi);
91
92/* CIRS RA,Dec. */
93 iauC2s(pi, &w, di);
94 *ri = iauAnp(w);
95
96/* Finished. */
97
98/*----------------------------------------------------------------------
99**
100** Copyright (C) 2015
101** Standards Of Fundamental Astronomy Board
102** of the International Astronomical Union.
103**
104** =====================
105** SOFA Software License
106** =====================
107**
108** NOTICE TO USER:
109**
110** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
111** CONDITIONS WHICH APPLY TO ITS USE.
112**
113** 1. The Software is owned by the IAU SOFA Board ("SOFA").
114**
115** 2. Permission is granted to anyone to use the SOFA software for any
116** purpose, including commercial applications, free of charge and
117** without payment of royalties, subject to the conditions and
118** restrictions listed below.
119**
120** 3. You (the user) may copy and distribute SOFA source code to others,
121** and use and adapt its code and algorithms in your own software,
122** on a world-wide, royalty-free basis. That portion of your
123** distribution that does not consist of intact and unchanged copies
124** of SOFA source code files is a "derived work" that must comply
125** with the following requirements:
126**
127** a) Your work shall be marked or carry a statement that it
128** (i) uses routines and computations derived by you from
129** software provided by SOFA under license to you; and
130** (ii) does not itself constitute software provided by and/or
131** endorsed by SOFA.
132**
133** b) The source code of your derived work must contain descriptions
134** of how the derived work is based upon, contains and/or differs
135** from the original SOFA software.
136**
137** c) The names of all routines in your derived work shall not
138** include the prefix "iau" or "sofa" or trivial modifications
139** thereof such as changes of case.
140**
141** d) The origin of the SOFA components of your derived work must
142** not be misrepresented; you must not claim that you wrote the
143** original software, nor file a patent application for SOFA
144** software or algorithms embedded in the SOFA software.
145**
146** e) These requirements must be reproduced intact in any source
147** distribution and shall apply to anyone to whom you have
148** granted a further right to modify the source code of your
149** derived work.
150**
151** Note that, as originally distributed, the SOFA software is
152** intended to be a definitive implementation of the IAU standards,
153** and consequently third-party modifications are discouraged. All
154** variations, no matter how minor, must be explicitly marked as
155** such, as explained above.
156**
157** 4. You shall not cause the SOFA software to be brought into
158** disrepute, either by misuse, or use for inappropriate tasks, or
159** by inappropriate modification.
160**
161** 5. The SOFA software is provided "as is" and SOFA makes no warranty
162** as to its use or performance. SOFA does not and cannot warrant
163** the performance or results which the user may obtain by using the
164** SOFA software. SOFA makes no warranties, express or implied, as
165** to non-infringement of third party rights, merchantability, or
166** fitness for any particular purpose. In no event will SOFA be
167** liable to the user for any consequential, incidental, or special
168** damages, including any lost profits or lost savings, even if a
169** SOFA representative has been advised of such damages, or for any
170** claim by any third party.
171**
172** 6. The provision of any version of the SOFA software under the terms
173** and conditions specified herein does not imply that future
174** versions will also be made available under the same terms and
175** conditions.
176*
177** In any published work or commercial product which uses the SOFA
178** software directly, acknowledgement (see www.iausofa.org) is
179** appreciated.
180**
181** Correspondence concerning SOFA software should be addressed as
182** follows:
183**
184** By email: sofa@ukho.gov.uk
185** By post: IAU SOFA Center
186** HM Nautical Almanac Office
187** UK Hydrographic Office
188** Admiralty Way, Taunton
189** Somerset, TA1 2DN
190** United Kingdom
191**
192**--------------------------------------------------------------------*/
193
194}
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