/* *+ * 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) not used * (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. * * The reference systems and timescales used are IAU 2006. * * Strictly speaking, the function is not valid for solar-system * sources, though the error will usually be extremely small. * 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 * . * 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, p1dvp1, p2[3], p3[3]; /* Unpack scalar and vector parameters. */ ab1 = amprms[11]; for( i = 0; i < 3; i++ ) { abv[i] = amprms[i+8]; } /* Spherical to x,y,z. */ eraS2c( rm, dm, p ); /* Aberration. */ p1dv = eraPdp( p, abv ); p1dvp1 = p1dv + 1.0; w = 1.0 + p1dv / ( ab1 + 1.0 ); for( i = 0; i < 3; i++ ) { p2[i] = ( ( ab1 * p[i] ) + ( w * abv[i] ) ) / p1dvp1; } /* Precession and nutation. */ eraRxp( (double(*)[3]) &rms[12], p2, p3 ); /* Geocentric apparent RA,dec. */ eraC2s( p3, ra, da ); *ra = eraAnp( *ra ); }