/*
*+
* Name:
* palMappa
* Purpose:
* Compute parameters needed by palAmpqk and palMapqk.
* Language:
* Starlink ANSI C
* Type of Module:
* Library routine
* Invocation:
* void palMappa( double eq, double date, double amprms[21] )
* Arguments:
* eq = double (Given)
* epoch of mean equinox to be used (Julian)
* date = double (Given)
* TDB (JD-2400000.5)
* amprms = double[21] (Returned)
* star-independent mean-to-apparent parameters:
* - (0) time interval for proper motion (Julian years)
* - (1-3) barycentric position of the Earth (AU)
* - (4-6) heliocentric direction of the Earth (unit vector)
* - (7) (grav rad Sun)*2/(Sun-Earth distance)
* - (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
* Description:
* Compute star-independent parameters in preparation for
* transformations between mean place and geocentric apparent place.
*
* The parameters produced by this function are required in the
* parallax, aberration, and nutation/bias/precession parts of the
* mean/apparent transformations.
*
* The reference systems and timescales used are IAU 2006.
* Notes:
* - For date, the distinction between the required TDB and TT
* is always negligible. Moreover, for all but the most
* critical applications UTC is adequate.
* - The vector amprms(1-3) is referred to the mean equinox and
* equator of epoch eq.
* - The parameters amprms produced by this function are used by
* palAmpqk, palMapqk and palMapqkz.
* 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) 2003 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
* .
* Bugs:
* {note_any_bugs_here}
*-
*/
#include "pal.h"
#include "palmac.h"
#include "pal1sofa.h"
#include
void palMappa( double eq, double date, double amprms[21] ){
/* Local constants */
/* Gravitational radius of the Sun x 2 (2*mu/c**2, AU) */
const double GR2 = 2.0 * 9.87063e-9;
/* Local Variables; */
int i;
double ebd[ 3 ], ehd[ 3 ], eh[ 3 ], e, vn[ 3 ], vm;
/* Initialise so that unsused values are returned holding zero */
memset( amprms, 0, 21*sizeof( *amprms ) );
/* Time interval for proper motion correction. */
amprms[ 0 ] = eraEpj( PAL__MJD0, date ) - eq;
/* Get Earth barycentric and heliocentric position and velocity. */
palEvp( date, eq, ebd, &rms[ 1 ], ehd, eh );
/* Heliocentric direction of Earth (normalized) and modulus. */
eraPn( eh, &e, &rms[ 4 ] );
/* Light deflection parameter */
amprms[7] = GR2 / e;
/* Aberration parameters. */
for( i = 0; i < 3; i++ ) {
amprms[ i + 8 ] = ebd[ i ]*PAL__CR;
}
eraPn( &rms[8], &vm, vn );
amprms[ 11 ] = sqrt( 1.0 - vm*vm );
/* NPB matrix. */
palPrenut( eq, date, (double(*)[ 3 ]) &rms[ 12 ] );
}