File Coverage

erfasrc/src/nut06a.c
Criterion Covered Total %
statement 7 7 100.0
branch n/a
condition n/a
subroutine n/a
pod n/a
total 7 7 100.0


line stmt bran cond sub pod time code
1             #include "erfa.h"
2              
3 23           void eraNut06a(double date1, double date2, double *dpsi, double *deps)
4             /*
5             ** - - - - - - - - - -
6             ** e r a N u t 0 6 a
7             ** - - - - - - - - - -
8             **
9             ** IAU 2000A nutation with adjustments to match the IAU 2006
10             ** precession.
11             **
12             ** Given:
13             ** date1,date2 double TT as a 2-part Julian Date (Note 1)
14             **
15             ** Returned:
16             ** dpsi,deps double nutation, luni-solar + planetary (Note 2)
17             **
18             ** Notes:
19             **
20             ** 1) The TT date date1+date2 is a Julian Date, apportioned in any
21             ** convenient way between the two arguments. For example,
22             ** JD(TT)=2450123.7 could be expressed in any of these ways,
23             ** among others:
24             **
25             ** date1 date2
26             **
27             ** 2450123.7 0.0 (JD method)
28             ** 2451545.0 -1421.3 (J2000 method)
29             ** 2400000.5 50123.2 (MJD method)
30             ** 2450123.5 0.2 (date & time method)
31             **
32             ** The JD method is the most natural and convenient to use in
33             ** cases where the loss of several decimal digits of resolution
34             ** is acceptable. The J2000 method is best matched to the way
35             ** the argument is handled internally and will deliver the
36             ** optimum resolution. The MJD method and the date & time methods
37             ** are both good compromises between resolution and convenience.
38             **
39             ** 2) The nutation components in longitude and obliquity are in radians
40             ** and with respect to the mean equinox and ecliptic of date,
41             ** IAU 2006 precession model (Hilton et al. 2006, Capitaine et al.
42             ** 2005).
43             **
44             ** 3) The function first computes the IAU 2000A nutation, then applies
45             ** adjustments for (i) the consequences of the change in obliquity
46             ** from the IAU 1980 ecliptic to the IAU 2006 ecliptic and (ii) the
47             ** secular variation in the Earth's dynamical form factor J2.
48             **
49             ** 4) The present function provides classical nutation, complementing
50             ** the IAU 2000 frame bias and IAU 2006 precession. It delivers a
51             ** pole which is at current epochs accurate to a few tens of
52             ** microarcseconds, apart from the free core nutation.
53             **
54             ** Called:
55             ** eraNut00a nutation, IAU 2000A
56             **
57             ** References:
58             **
59             ** Chapront, J., Chapront-Touze, M. & Francou, G. 2002,
60             ** Astron.Astrophys. 387, 700
61             **
62             ** Lieske, J.H., Lederle, T., Fricke, W. & Morando, B. 1977,
63             ** Astron.Astrophys. 58, 1-16
64             **
65             ** Mathews, P.M., Herring, T.A., Buffet, B.A. 2002, J.Geophys.Res.
66             ** 107, B4. The MHB_2000 code itself was obtained on 9th September
67             ** 2002 from ftp//maia.usno.navy.mil/conv2000/chapter5/IAU2000A.
68             **
69             ** Simon, J.-L., Bretagnon, P., Chapront, J., Chapront-Touze, M.,
70             ** Francou, G., Laskar, J. 1994, Astron.Astrophys. 282, 663-683
71             **
72             ** Souchay, J., Loysel, B., Kinoshita, H., Folgueira, M. 1999,
73             ** Astron.Astrophys.Supp.Ser. 135, 111
74             **
75             ** Wallace, P.T., "Software for Implementing the IAU 2000
76             ** Resolutions", in IERS Workshop 5.1 (2002)
77             **
78             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
79             ** Derived, with permission, from the SOFA library. See notes at end of file.
80             */
81             {
82             double t, fj2, dp, de;
83              
84              
85             /* Interval between fundamental date J2000.0 and given date (JC). */
86 23           t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
87              
88             /* Factor correcting for secular variation of J2. */
89 23           fj2 = -2.7774e-6 * t;
90              
91             /* Obtain IAU 2000A nutation. */
92 23           eraNut00a(date1, date2, &dp, &de);
93              
94             /* Apply P03 adjustments (Wallace & Capitaine, 2006, Eqs.5). */
95 23           *dpsi = dp + dp * (0.4697e-6 + fj2);
96 23           *deps = de + de * fj2;
97              
98 23           return;
99              
100             }
101             /*----------------------------------------------------------------------
102             **
103             **
104             ** Copyright (C) 2013-2019, NumFOCUS Foundation.
105             ** All rights reserved.
106             **
107             ** This library is derived, with permission, from the International
108             ** Astronomical Union's "Standards of Fundamental Astronomy" library,
109             ** available from http://www.iausofa.org.
110             **
111             ** The ERFA version is intended to retain identical functionality to
112             ** the SOFA library, but made distinct through different function and
113             ** file names, as set out in the SOFA license conditions. The SOFA
114             ** original has a role as a reference standard for the IAU and IERS,
115             ** and consequently redistribution is permitted only in its unaltered
116             ** state. The ERFA version is not subject to this restriction and
117             ** therefore can be included in distributions which do not support the
118             ** concept of "read only" software.
119             **
120             ** Although the intent is to replicate the SOFA API (other than
121             ** replacement of prefix names) and results (with the exception of
122             ** bugs; any that are discovered will be fixed), SOFA is not
123             ** responsible for any errors found in this version of the library.
124             **
125             ** If you wish to acknowledge the SOFA heritage, please acknowledge
126             ** that you are using a library derived from SOFA, rather than SOFA
127             ** itself.
128             **
129             **
130             ** TERMS AND CONDITIONS
131             **
132             ** Redistribution and use in source and binary forms, with or without
133             ** modification, are permitted provided that the following conditions
134             ** are met:
135             **
136             ** 1 Redistributions of source code must retain the above copyright
137             ** notice, this list of conditions and the following disclaimer.
138             **
139             ** 2 Redistributions in binary form must reproduce the above copyright
140             ** notice, this list of conditions and the following disclaimer in
141             ** the documentation and/or other materials provided with the
142             ** distribution.
143             **
144             ** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
145             ** the International Astronomical Union nor the names of its
146             ** contributors may be used to endorse or promote products derived
147             ** from this software without specific prior written permission.
148             **
149             ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
150             ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
151             ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
152             ** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
153             ** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
154             ** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
155             ** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
156             ** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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158             ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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161             **
162             */