| 1 | /*
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| 2 | *+
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| 3 | * Name:
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| 4 | * palGe50
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| 5 |
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| 6 | * Purpose:
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| 7 | * Transform Galactic Coordinate to B1950 FK4
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| 8 |
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| 9 | * Language:
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| 10 | * Starlink ANSI C
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| 11 |
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| 12 | * Type of Module:
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| 13 | * Library routine
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| 14 |
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| 15 | * Invocation:
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| 16 | * palGe50( double dl, double db, double *dr, double *dd );
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| 17 |
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| 18 | * Arguments:
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| 19 | * dl = double (Given)
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| 20 | * Galactic longitude (radians)
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| 21 | * db = double (Given)
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| 22 | * Galactic latitude (radians)
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| 23 | * dr = double * (Returned)
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| 24 | * B9150.0 FK4 RA.
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| 25 | * dd = double * (Returned)
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| 26 | * B1950.0 FK4 Dec.
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| 27 |
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| 28 | * Description:
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| 29 | * Transformation from IAU 1958 galactic coordinates to
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| 30 | * B1950.0 'FK4' equatorial coordinates.
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| 31 |
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| 32 | * Authors:
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| 33 | * PTW: Patrick T. Wallace
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| 34 | * TIMJ: Tim Jenness (JAC, Hawaii)
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| 35 | * {enter_new_authors_here}
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| 36 |
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| 37 | * Notes:
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| 38 | * - The equatorial coordinates are B1950.0 'FK4'. Use the routine
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| 39 | * palGaleq if conversion to J2000.0 coordinates is required.
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| 40 |
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| 41 | * See Also:
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| 42 | * - Blaauw et al, Mon.Not.R.Astron.Soc.,121,123 (1960)
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| 43 |
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| 44 | * History:
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| 45 | * 2012-03-23 (TIMJ):
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| 46 | * Initial version
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| 47 | * Adapted with permission from the Fortran SLALIB library.
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| 48 | * {enter_further_changes_here}
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| 49 |
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| 50 | * Copyright:
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| 51 | * Copyright (C) 1995 Rutherford Appleton Laboratory
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| 52 | * Copyright (C) 2012 Science and Technology Facilities Council.
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| 53 | * All Rights Reserved.
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| 54 |
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| 55 | * Licence:
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| 56 | * This program is free software; you can redistribute it and/or
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| 57 | * modify it under the terms of the GNU General Public License as
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| 58 | * published by the Free Software Foundation; either version 3 of
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| 59 | * the License, or (at your option) any later version.
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| 60 | *
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| 61 | * This program is distributed in the hope that it will be
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| 62 | * useful, but WITHOUT ANY WARRANTY; without even the implied
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| 63 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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| 64 | * PURPOSE. See the GNU General Public License for more details.
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| 65 | *
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| 66 | * You should have received a copy of the GNU General Public License
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| 67 | * along with this program; if not, write to the Free Software
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| 68 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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| 69 | * MA 02110-1301, USA.
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| 70 |
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| 71 | * Bugs:
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| 72 | * {note_any_bugs_here}
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| 73 | *-
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| 74 | */
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| 75 |
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| 76 | #include "pal.h"
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| 77 | #include "pal1sofa.h"
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| 78 |
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| 79 | void palGe50 ( double dl, double db, double * dr, double * dd ) {
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| 80 |
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| 81 | /*
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| 82 | * L2,B2 system of galactic coordinates
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| 83 | *
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| 84 | * P = 192.25 RA of galactic north pole (mean B1950.0)
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| 85 | * Q = 62.6 inclination of galactic to mean B1950.0 equator
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| 86 | * R = 33 longitude of ascending node
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| 87 | *
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| 88 | * P,Q,R are degrees
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| 89 | *
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| 90 | *
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| 91 | * Equatorial to galactic rotation matrix
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| 92 | *
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| 93 | * The Euler angles are P, Q, 90-R, about the z then y then
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| 94 | * z axes.
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| 95 | *
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| 96 | * +CP.CQ.SR-SP.CR +SP.CQ.SR+CP.CR -SQ.SR
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| 97 | *
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| 98 | * -CP.CQ.CR-SP.SR -SP.CQ.CR+CP.SR +SQ.CR
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| 99 | *
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| 100 | * +CP.SQ +SP.SQ +CQ
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| 101 | *
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| 102 | */
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| 103 |
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| 104 | double rmat[3][3] = {
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| 105 | { -0.066988739415,-0.872755765852,-0.483538914632 },
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| 106 | { +0.492728466075,-0.450346958020,+0.744584633283 },
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| 107 | { -0.867600811151,-0.188374601723,+0.460199784784 }
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| 108 | };
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| 109 |
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| 110 | double v1[3], v2[3], r, d, re, de;
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| 111 |
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| 112 | /* Spherical to cartesian */
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| 113 | eraS2c( dl, db, v1 );
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| 114 |
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| 115 | /* Rotate to mean B1950.0 */
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| 116 | eraTrxp( rmat, v1, v2 );
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| 117 |
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| 118 | /* Cartesian to spherical */
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| 119 | eraC2s( v2, &r, &d );
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| 120 |
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| 121 | /* Introduce E-terms */
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| 122 | palAddet( r, d, 1950.0, &re, &de );
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| 123 |
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| 124 | /* Express in conventional ranges */
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| 125 | *dr = eraAnp( re );
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| 126 | *dd = eraAnpm( de );
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| 127 |
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| 128 | }
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