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/*
*+
* Name:
* palMapqkz
* Purpose:
* Quick mean to apparent place (no proper motion or parallax).
* Language:
* Starlink ANSI C
* Type of Module:
* Library routine
* Invocation:
* void palMapqkz( double rm, double dm, double amprms[21],
* double *ra, double *da )
* Arguments:
* rm = double (Given)
* Mean RA (radians).
* dm = double (Given)
* Mean Dec (radians).
* amprms = double[21] (Given)
* Star-independent mean-to-apparent parameters (see palMappa):
* (0-3) not used
* (4-6) heliocentric direction of the Earth (unit vector)
* (7) not used
* (8-10) abv: barycentric Earth velocity in units of c
* (11) sqrt(1-v^2) where v=modulus(abv)
* (12-20) precession/nutation (3,3) matrix
* ra = double * (Returned)
* Apparent RA (radians).
* da = double * (Returned)
* Apparent Dec (radians).
* Description:
* Quick mean to apparent place: transform a star RA,dec from
* mean place to geocentric apparent place, given the
* star-independent parameters, and assuming zero parallax
* and proper motion.
*
* Use of this function is appropriate when efficiency is important
* and where many star positions, all with parallax and proper
* motion either zero or already allowed for, and all referred to
* the same equator and equinox, are to be transformed for one
* epoch. The star-independent parameters can be obtained by
* calling the palMappa function.
*
* The corresponding function for the case of non-zero parallax
* and proper motion is palMapqk.
* Notes:
* - The reference systems and timescales used are IAU 2006.
* - The mean place rm, dm and the vectors amprms[1-3] and amprms[4-6]
* are referred to the mean equinox and equator of the epoch
* specified when generating the precession/nutation matrix
* amprms[12-20]. In the call to palMappa (q.v.) normally used
* to populate amprms, this epoch is the first argument (eq).
* - The vector amprms(4-6) is referred to the mean equinox and
* equator of epoch eq.
* - Strictly speaking, the routine is not valid for solar-system
* sources, though the error will usually be extremely small.
* However, to prevent gross errors in the case where the
* position of the Sun is specified, the gravitational
* deflection term is restrained within about 920 arcsec of the
* centre of the Sun's disc. The term has a maximum value of
* about 1.85 arcsec at this radius, and decreases to zero as
* the centre of the disc is approached.
* Authors:
* PTW: Pat Wallace (STFC)
* {enter_new_authors_here}
* History:
* 2012-02-13 (PTW):
* Initial version.
* 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 palMapqkz ( double rm, double dm, double amprms[21], double *ra,
double *da ){
/* Local Variables: */
int i;
double ab1, abv[3], p[3], w, p1dv, p2[3], p3[3];
double gr2e, pde, pdep1, ehn[3], p1[3];
/* Unpack scalar and vector parameters. */
ab1 = amprms[11];
gr2e = amprms[7];
for( i = 0; i < 3; i++ ) {
abv[i] = amprms[i+8];
ehn[i] = amprms[i+4];
}
/* Spherical to x,y,z. */
eraS2c( rm, dm, p );
/* Light deflection (restrained within the Sun's disc) */
pde = eraPdp( p, ehn );
pdep1 = pde + 1.0;
w = gr2e / ( pdep1 > 1.0e-5 ? pdep1 : 1.0e-5 );
for( i = 0; i < 3; i++) {
p1[i] = p[i] + w * ( ehn[i] - pde * p[i] );
}
/* Aberration. */
p1dv = eraPdp( p1, abv );
w = 1.0 + p1dv / ( ab1 + 1.0 );
for( i = 0; i < 3; i++ ) {
p2[i] = ( ( ab1 * p1[i] ) + ( w * abv[i] ) );
}
/* Precession and nutation. */
eraRxp( (double(*)[3]) &rms[12], p2, p3 );
/* Geocentric apparent RA,dec. */
eraC2s( p3, ra, da );
*ra = eraAnp( *ra );
}
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