File Coverage

erfasrc/src/eqeq94.c

Criterion	Covered	Total	%
statement	0	9	0.0
branch			n/a
condition			n/a
subroutine			n/a
pod			n/a
total	0	9	0.0

line	stmt	code
1		#include "erfa.h"
2
3	0	double eraEqeq94(double date1, double date2)
4		/*
5		** - - - - - - - - - -
6		** e r a E q e q 9 4
7		** - - - - - - - - - -
8		**
9		** Equation of the equinoxes, IAU 1994 model.
10		**
11		** Given:
12		** date1,date2 double TDB date (Note 1)
13		**
14		** Returned (function value):
15		** double equation of the equinoxes (Note 2)
16		**
17		** Notes:
18		**
19		** 1) The date date1+date2 is a Julian Date, apportioned in any
20		** convenient way between the two arguments. For example,
21		** JD(TT)=2450123.7 could be expressed in any of these ways,
22		** among others:
23		**
24		** date1 date2
25		**
26		** 2450123.7 0.0 (JD method)
27		** 2451545.0 -1421.3 (J2000 method)
28		** 2400000.5 50123.2 (MJD method)
29		** 2450123.5 0.2 (date & time method)
30		**
31		** The JD method is the most natural and convenient to use in
32		** cases where the loss of several decimal digits of resolution
33		** is acceptable. The J2000 method is best matched to the way
34		** the argument is handled internally and will deliver the
35		** optimum resolution. The MJD method and the date & time methods
36		** are both good compromises between resolution and convenience.
37		**
38		** 2) The result, which is in radians, operates in the following sense:
39		**
40		** Greenwich apparent ST = GMST + equation of the equinoxes
41		**
42		** Called:
43		** eraAnpm normalize angle into range +/- pi
44		** eraNut80 nutation, IAU 1980
45		** eraObl80 mean obliquity, IAU 1980
46		**
47		** References:
48		**
49		** IAU Resolution C7, Recommendation 3 (1994).
50		**
51		** Capitaine, N. & Gontier, A.-M., 1993, Astron.Astrophys., 275,
52		** 645-650.
53		**
54		** Copyright (C) 2013-2019, NumFOCUS Foundation.
55		** Derived, with permission, from the SOFA library. See notes at end of file.
56		*/
57		{
58		double t, om, dpsi, deps, eps0, ee;
59
60
61		/* Interval between fundamental epoch J2000.0 and given date (JC). */
62	0	t = ((date1 - ERFA_DJ00) + date2) / ERFA_DJC;
63
64		/* Longitude of the mean ascending node of the lunar orbit on the */
65		/* ecliptic, measured from the mean equinox of date. */
66	0	om = eraAnpm((450160.280 + (-482890.539
67	0	+ (7.455 + 0.008 * t) * t) * t) * ERFA_DAS2R
68	0	+ fmod(-5.0 * t, 1.0) * ERFA_D2PI);
69
70		/* Nutation components and mean obliquity. */
71	0	eraNut80(date1, date2, &dpsi, &deps);
72	0	eps0 = eraObl80(date1, date2);
73
74		/* Equation of the equinoxes. */
75	0	ee = dpsicos(eps0) + ERFA_DAS2R(0.00264sin(om) + 0.000063sin(om+om));
76
77	0	return ee;
78
79		}
80		/*----------------------------------------------------------------------
81		**
82		**
83		** Copyright (C) 2013-2019, NumFOCUS Foundation.
84		** All rights reserved.
85		**
86		** This library is derived, with permission, from the International
87		** Astronomical Union's "Standards of Fundamental Astronomy" library,
88		** available from http://www.iausofa.org.
89		**
90		** The ERFA version is intended to retain identical functionality to
91		** the SOFA library, but made distinct through different function and
92		** file names, as set out in the SOFA license conditions. The SOFA
93		** original has a role as a reference standard for the IAU and IERS,
94		** and consequently redistribution is permitted only in its unaltered
95		** state. The ERFA version is not subject to this restriction and
96		** therefore can be included in distributions which do not support the
97		** concept of "read only" software.
98		**
99		** Although the intent is to replicate the SOFA API (other than
100		** replacement of prefix names) and results (with the exception of
101		** bugs; any that are discovered will be fixed), SOFA is not
102		** responsible for any errors found in this version of the library.
103		**
104		** If you wish to acknowledge the SOFA heritage, please acknowledge
105		** that you are using a library derived from SOFA, rather than SOFA
106		** itself.
107		**
108		**
109		** TERMS AND CONDITIONS
110		**
111		** Redistribution and use in source and binary forms, with or without
112		** modification, are permitted provided that the following conditions
113		** are met:
114		**
115		** 1 Redistributions of source code must retain the above copyright
116		** notice, this list of conditions and the following disclaimer.
117		**
118		** 2 Redistributions in binary form must reproduce the above copyright
119		** notice, this list of conditions and the following disclaimer in
120		** the documentation and/or other materials provided with the
121		** distribution.
122		**
123		** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
124		** the International Astronomical Union nor the names of its
125		** contributors may be used to endorse or promote products derived
126		** from this software without specific prior written permission.
127		**
128		** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
129		** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
130		** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
131		** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
132		** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
133		** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
134		** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
135		** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
136		** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
137		** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
138		** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
139		** POSSIBILITY OF SUCH DAMAGE.
140		**
141		*/