/*
*+
* Name:
* palGalsup
* Purpose:
* Convert from galactic to supergalactic coordinates
* Language:
* Starlink ANSI C
* Type of Module:
* Library routine
* Invocation:
* void palGalsup ( double dl, double db, double *dsl, double *dsb );
* Arguments:
* dl = double (Given)
* Galactic longitude.
* db = double (Given)
* Galactic latitude.
* dsl = double * (Returned)
* Supergalactic longitude.
* dsb = double * (Returned)
* Supergalactic latitude.
* Description:
* Transformation from IAU 1958 galactic coordinates to
* de Vaucouleurs supergalactic coordinates.
* Authors:
* PTW: Pat Wallace (STFC)
* TIMJ: Tim Jenness (JAC, Hawaii)
* {enter_new_authors_here}
* See Also:
* - de Vaucouleurs, de Vaucouleurs, & Corwin, Second Reference
* Catalogue of Bright Galaxies, U. Texas, page 8.
* - Systems & Applied Sciences Corp., Documentation for the
* machine-readable version of the above catalogue,
* Contract NAS 5-26490.
*
* (These two references give different values for the galactic
* longitude of the supergalactic origin. Both are wrong; the
* correct value is L2=137.37.)
* History:
* 2012-02-12(TIMJ):
* Initial version with documentation taken from Fortran SLA
* Adapted with permission from the Fortran SLALIB library.
* {enter_further_changes_here}
* Copyright:
* Copyright (C) 1999 Rutherford Appleton Laboratory
* Copyright (C) 2012 Science and Technology Facilities Council.
* All Rights Reserved.
* Licence:
* This program is free software: you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, either
* version 3 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* License along with this program. If not, see
* <http://www.gnu.org/licenses/>.
* Bugs:
* {note_any_bugs_here}
*-
*/
#include "pal.h"
#include "pal1sofa.h"
void palGalsup ( double dl, double db, double *dsl, double *dsb ) {
double v1[3];
double v2[3];
/*
* System of supergalactic coordinates:
*
* SGL SGB L2 B2 (deg)
* - +90 47.37 +6.32
* 0 0 - 0
*
* Galactic to supergalactic rotation matrix:
*/
double rmat[3][3] = {
{ -0.735742574804,+0.677261296414,+0.000000000000 },
{ -0.074553778365,-0.080991471307,+0.993922590400 },
{ +0.673145302109,+0.731271165817,+0.110081262225 }
};
/* Spherical to Cartesian */
eraS2c( dl, db, v1 );
/* Galactic to Supergalactic */
eraRxp( rmat, v1, v2 );
/* Cartesian to spherical */
eraC2s( v2, dsl, dsb );
/* Express in conventional ranges */
*dsl = eraAnp( *dsl );
*dsb = eraAnpm( *dsb );
}