File Coverage

erfasrc/src/gst94.c

Criterion	Covered	Total	%
statement	0	5	0.0
branch			n/a
condition			n/a
subroutine			n/a
pod			n/a
total	0	5	0.0

line	stmt	code
1		#include "erfa.h"
2
3	0	double eraGst94(double uta, double utb)
4		/*
5		** - - - - - - - - -
6		** e r a G s t 9 4
7		** - - - - - - - - -
8		**
9		** Greenwich apparent sidereal time (consistent with IAU 1982/94
10		** resolutions).
11		**
12		** Given:
13		** uta,utb double UT1 as a 2-part Julian Date (Notes 1,2)
14		**
15		** Returned (function value):
16		** double Greenwich apparent sidereal time (radians)
17		**
18		** Notes:
19		**
20		** 1) The UT1 date uta+utb is a Julian Date, apportioned in any
21		** convenient way between the argument pair. For example,
22		** JD=2450123.7 could be expressed in any of these ways, among
23		** others:
24		**
25		** uta utb
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 cases
33		** where the loss of several decimal digits of resolution is
34		** acceptable. The J2000 and MJD methods are good compromises
35		** between resolution and convenience. For UT, the date & time
36		** method is best matched to the algorithm that is used by the Earth
37		** Rotation Angle function, called internally: maximum precision is
38		** delivered when the uta argument is for 0hrs UT1 on the day in
39		** question and the utb argument lies in the range 0 to 1, or vice
40		** versa.
41		**
42		** 2) The result is compatible with the IAU 1982 and 1994 resolutions,
43		** except that accuracy has been compromised for the sake of
44		** convenience in that UT is used instead of TDB (or TT) to compute
45		** the equation of the equinoxes.
46		**
47		** 3) This GAST must be used only in conjunction with contemporaneous
48		** IAU standards such as 1976 precession, 1980 obliquity and 1982
49		** nutation. It is not compatible with the IAU 2000 resolutions.
50		**
51		** 4) The result is returned in the range 0 to 2pi.
52		**
53		** Called:
54		** eraGmst82 Greenwich mean sidereal time, IAU 1982
55		** eraEqeq94 equation of the equinoxes, IAU 1994
56		** eraAnp normalize angle into range 0 to 2pi
57		**
58		** References:
59		**
60		** Explanatory Supplement to the Astronomical Almanac,
61		** P. Kenneth Seidelmann (ed), University Science Books (1992)
62		**
63		** IAU Resolution C7, Recommendation 3 (1994)
64		**
65		** Copyright (C) 2013-2020, NumFOCUS Foundation.
66		** Derived, with permission, from the SOFA library. See notes at end of file.
67		*/
68		{
69		double gmst82, eqeq94, gst;
70
71
72	0	gmst82 = eraGmst82(uta, utb);
73	0	eqeq94 = eraEqeq94(uta, utb);
74	0	gst = eraAnp(gmst82 + eqeq94);
75
76	0	return gst;
77
78		}
79		/*----------------------------------------------------------------------
80		**
81		**
82		** Copyright (C) 2013-2020, NumFOCUS Foundation.
83		** All rights reserved.
84		**
85		** This library is derived, with permission, from the International
86		** Astronomical Union's "Standards of Fundamental Astronomy" library,
87		** available from http://www.iausofa.org.
88		**
89		** The ERFA version is intended to retain identical functionality to
90		** the SOFA library, but made distinct through different function and
91		** file names, as set out in the SOFA license conditions. The SOFA
92		** original has a role as a reference standard for the IAU and IERS,
93		** and consequently redistribution is permitted only in its unaltered
94		** state. The ERFA version is not subject to this restriction and
95		** therefore can be included in distributions which do not support the
96		** concept of "read only" software.
97		**
98		** Although the intent is to replicate the SOFA API (other than
99		** replacement of prefix names) and results (with the exception of
100		** bugs; any that are discovered will be fixed), SOFA is not
101		** responsible for any errors found in this version of the library.
102		**
103		** If you wish to acknowledge the SOFA heritage, please acknowledge
104		** that you are using a library derived from SOFA, rather than SOFA
105		** itself.
106		**
107		**
108		** TERMS AND CONDITIONS
109		**
110		** Redistribution and use in source and binary forms, with or without
111		** modification, are permitted provided that the following conditions
112		** are met:
113		**
114		** 1 Redistributions of source code must retain the above copyright
115		** notice, this list of conditions and the following disclaimer.
116		**
117		** 2 Redistributions in binary form must reproduce the above copyright
118		** notice, this list of conditions and the following disclaimer in
119		** the documentation and/or other materials provided with the
120		** distribution.
121		**
122		** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
123		** the International Astronomical Union nor the names of its
124		** contributors may be used to endorse or promote products derived
125		** from this software without specific prior written permission.
126		**
127		** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
128		** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
129		** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
130		** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
131		** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
132		** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
133		** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
134		** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
135		** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
136		** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
137		** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
138		** POSSIBILITY OF SUCH DAMAGE.
139		**
140		*/