source: trunk/FACT++/pal/palSupgal.c@ 18597

Last change on this file since 18597 was 18347, checked in by tbretz, 9 years ago
File size: 3.1 KB
Line 
1/*
2*+
3* Name:
4* palSupgal
5
6* Purpose:
7* Convert from supergalactic to galactic coordinates
8
9* Language:
10* Starlink ANSI C
11
12* Type of Module:
13* Library routine
14
15* Invocation:
16* void palSupgal ( double dsl, double dsb, double *dl, double *db );
17
18* Arguments:
19* dsl = double (Given)
20* Supergalactic longitude.
21* dsb = double (Given)
22* Supergalactic latitude.
23* dl = double * (Returned)
24* Galactic longitude.
25* db = double * (Returned)
26* Galactic latitude.
27
28* Description:
29* Transformation from de Vaucouleurs supergalactic coordinates
30* to IAU 1958 galactic coordinates
31
32* Authors:
33* PTW: Pat Wallace (STFC)
34* TIMJ: Tim Jenness (JAC, Hawaii)
35* {enter_new_authors_here}
36
37* See Also:
38* - de Vaucouleurs, de Vaucouleurs, & Corwin, Second Reference
39* Catalogue of Bright Galaxies, U. Texas, page 8.
40* - Systems & Applied Sciences Corp., Documentation for the
41* machine-readable version of the above catalogue,
42* Contract NAS 5-26490.
43*
44* (These two references give different values for the galactic
45* longitude of the supergalactic origin. Both are wrong; the
46* correct value is L2=137.37.)
47
48* History:
49* 2012-02-12(TIMJ):
50* Initial version with documentation taken from Fortran SLA
51* Adapted with permission from the Fortran SLALIB library.
52* {enter_further_changes_here}
53
54* Copyright:
55* Copyright (C) 1995 Rutherford Appleton Laboratory
56* Copyright (C) 2012 Science and Technology Facilities Council.
57* All Rights Reserved.
58
59* Licence:
60* This program is free software: you can redistribute it and/or
61* modify it under the terms of the GNU Lesser General Public
62* License as published by the Free Software Foundation, either
63* version 3 of the License, or (at your option) any later
64* version.
65*
66* This program is distributed in the hope that it will be useful,
67* but WITHOUT ANY WARRANTY; without even the implied warranty of
68* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
69* GNU Lesser General Public License for more details.
70*
71* You should have received a copy of the GNU Lesser General
72* License along with this program. If not, see
73* <http://www.gnu.org/licenses/>.
74
75* Bugs:
76* {note_any_bugs_here}
77*-
78*/
79
80#include "pal.h"
81#include "pal1sofa.h"
82
83void palSupgal ( double dsl, double dsb, double *dl, double *db ) {
84
85 double v1[3];
86 double v2[3];
87
88/*
89* System of supergalactic coordinates:
90*
91* SGL SGB L2 B2 (deg)
92* - +90 47.37 +6.32
93* 0 0 - 0
94*
95* Galactic to supergalactic rotation matrix:
96*/
97 double rmat[3][3] = {
98 { -0.735742574804,+0.677261296414,+0.000000000000 },
99 { -0.074553778365,-0.080991471307,+0.993922590400 },
100 { +0.673145302109,+0.731271165817,+0.110081262225 }
101 };
102
103 /* Spherical to Cartesian */
104 eraS2c( dsl, dsb, v1 );
105
106 /* Supergalactic to galactic */
107 eraTrxp( rmat, v1, v2 );
108
109 /* Cartesian to spherical */
110 eraC2s( v2, dl, db );
111
112 /* Express in conventional ranges */
113 *dl = eraAnp( *dl );
114 *db = eraAnpm( *db );
115
116}
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