source: trunk/FACT++/sofa/src/aper13.c@ 18375

Last change on this file since 18375 was 18346, checked in by tbretz, 11 years ago
File size: 9.0 KB
Line 
1#include "sofa.h"
2
3void iauAper13(double ut11, double ut12, iauASTROM *astrom)
4/*
5** - - - - - - - - - -
6** i a u A p e r 1 3
7** - - - - - - - - - -
8**
9** In the star-independent astrometry parameters, update only the
10** Earth rotation angle. The caller provides UT1, (n.b. not UTC).
11**
12** This function is part of the International Astronomical Union's
13** SOFA (Standards of Fundamental Astronomy) software collection.
14**
15** Status: support function.
16**
17** Given:
18** ut11 double UT1 as a 2-part...
19** ut12 double ...Julian Date (Note 1)
20** astrom iauASTROM* star-independent astrometry parameters:
21** pmt double not used
22** eb double[3] not used
23** eh double[3] not used
24** em double not used
25** v double[3] not used
26** bm1 double not used
27** bpn double[3][3] not used
28** along double longitude + s' (radians)
29** xpl double not used
30** ypl double not used
31** sphi double not used
32** cphi double not used
33** diurab double not used
34** eral double not used
35** refa double not used
36** refb double not used
37**
38** Returned:
39** astrom iauASTROM* star-independent astrometry parameters:
40** pmt double unchanged
41** eb double[3] unchanged
42** eh double[3] unchanged
43** em double unchanged
44** v double[3] unchanged
45** bm1 double unchanged
46** bpn double[3][3] unchanged
47** along double unchanged
48** xpl double unchanged
49** ypl double unchanged
50** sphi double unchanged
51** cphi double unchanged
52** diurab double unchanged
53** eral double "local" Earth rotation angle (radians)
54** refa double unchanged
55** refb double unchanged
56**
57** Notes:
58**
59** 1) The UT1 date (n.b. not UTC) ut11+ut12 is a Julian Date,
60** apportioned in any convenient way between the arguments ut11 and
61** ut12. For example, JD(UT1)=2450123.7 could be expressed in any
62** of these ways, among others:
63**
64** ut11 ut12
65**
66** 2450123.7 0.0 (JD method)
67** 2451545.0 -1421.3 (J2000 method)
68** 2400000.5 50123.2 (MJD method)
69** 2450123.5 0.2 (date & time method)
70**
71** The JD method is the most natural and convenient to use in cases
72** where the loss of several decimal digits of resolution is
73** acceptable. The J2000 and MJD methods are good compromises
74** between resolution and convenience. The date & time method is
75** best matched to the algorithm used: maximum precision is
76** delivered when the ut11 argument is for 0hrs UT1 on the day in
77** question and the ut12 argument lies in the range 0 to 1, or vice
78** versa.
79**
80** 2) If the caller wishes to provide the Earth rotation angle itself,
81** the function iauAper can be used instead. One use of this
82** technique is to substitute Greenwich apparent sidereal time and
83** thereby to support equinox based transformations directly.
84**
85** 3) This is one of several functions that inserts into the astrom
86** structure star-independent parameters needed for the chain of
87** astrometric transformations ICRS <-> GCRS <-> CIRS <-> observed.
88**
89** The various functions support different classes of observer and
90** portions of the transformation chain:
91**
92** functions observer transformation
93**
94** iauApcg iauApcg13 geocentric ICRS <-> GCRS
95** iauApci iauApci13 terrestrial ICRS <-> CIRS
96** iauApco iauApco13 terrestrial ICRS <-> observed
97** iauApcs iauApcs13 space ICRS <-> GCRS
98** iauAper iauAper13 terrestrial update Earth rotation
99** iauApio iauApio13 terrestrial CIRS <-> observed
100**
101** Those with names ending in "13" use contemporary SOFA models to
102** compute the various ephemerides. The others accept ephemerides
103** supplied by the caller.
104**
105** The transformation from ICRS to GCRS covers space motion,
106** parallax, light deflection, and aberration. From GCRS to CIRS
107** comprises frame bias and precession-nutation. From CIRS to
108** observed takes account of Earth rotation, polar motion, diurnal
109** aberration and parallax (unless subsumed into the ICRS <-> GCRS
110** transformation), and atmospheric refraction.
111**
112** Called:
113** iauAper astrometry parameters: update ERA
114** iauEra00 Earth rotation angle, IAU 2000
115**
116** This revision: 2013 September 25
117**
118** SOFA release 2015-02-09
119**
120** Copyright (C) 2015 IAU SOFA Board. See notes at end.
121*/
122{
123 iauAper(iauEra00(ut11,ut12), astrom);
124
125/* Finished. */
126
127/*----------------------------------------------------------------------
128**
129** Copyright (C) 2015
130** Standards Of Fundamental Astronomy Board
131** of the International Astronomical Union.
132**
133** =====================
134** SOFA Software License
135** =====================
136**
137** NOTICE TO USER:
138**
139** BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
140** CONDITIONS WHICH APPLY TO ITS USE.
141**
142** 1. The Software is owned by the IAU SOFA Board ("SOFA").
143**
144** 2. Permission is granted to anyone to use the SOFA software for any
145** purpose, including commercial applications, free of charge and
146** without payment of royalties, subject to the conditions and
147** restrictions listed below.
148**
149** 3. You (the user) may copy and distribute SOFA source code to others,
150** and use and adapt its code and algorithms in your own software,
151** on a world-wide, royalty-free basis. That portion of your
152** distribution that does not consist of intact and unchanged copies
153** of SOFA source code files is a "derived work" that must comply
154** with the following requirements:
155**
156** a) Your work shall be marked or carry a statement that it
157** (i) uses routines and computations derived by you from
158** software provided by SOFA under license to you; and
159** (ii) does not itself constitute software provided by and/or
160** endorsed by SOFA.
161**
162** b) The source code of your derived work must contain descriptions
163** of how the derived work is based upon, contains and/or differs
164** from the original SOFA software.
165**
166** c) The names of all routines in your derived work shall not
167** include the prefix "iau" or "sofa" or trivial modifications
168** thereof such as changes of case.
169**
170** d) The origin of the SOFA components of your derived work must
171** not be misrepresented; you must not claim that you wrote the
172** original software, nor file a patent application for SOFA
173** software or algorithms embedded in the SOFA software.
174**
175** e) These requirements must be reproduced intact in any source
176** distribution and shall apply to anyone to whom you have
177** granted a further right to modify the source code of your
178** derived work.
179**
180** Note that, as originally distributed, the SOFA software is
181** intended to be a definitive implementation of the IAU standards,
182** and consequently third-party modifications are discouraged. All
183** variations, no matter how minor, must be explicitly marked as
184** such, as explained above.
185**
186** 4. You shall not cause the SOFA software to be brought into
187** disrepute, either by misuse, or use for inappropriate tasks, or
188** by inappropriate modification.
189**
190** 5. The SOFA software is provided "as is" and SOFA makes no warranty
191** as to its use or performance. SOFA does not and cannot warrant
192** the performance or results which the user may obtain by using the
193** SOFA software. SOFA makes no warranties, express or implied, as
194** to non-infringement of third party rights, merchantability, or
195** fitness for any particular purpose. In no event will SOFA be
196** liable to the user for any consequential, incidental, or special
197** damages, including any lost profits or lost savings, even if a
198** SOFA representative has been advised of such damages, or for any
199** claim by any third party.
200**
201** 6. The provision of any version of the SOFA software under the terms
202** and conditions specified herein does not imply that future
203** versions will also be made available under the same terms and
204** conditions.
205*
206** In any published work or commercial product which uses the SOFA
207** software directly, acknowledgement (see www.iausofa.org) is
208** appreciated.
209**
210** Correspondence concerning SOFA software should be addressed as
211** follows:
212**
213** By email: sofa@ukho.gov.uk
214** By post: IAU SOFA Center
215** HM Nautical Almanac Office
216** UK Hydrographic Office
217** Admiralty Way, Taunton
218** Somerset, TA1 2DN
219** United Kingdom
220**
221**--------------------------------------------------------------------*/
222
223}
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