| 1 | /*
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| 2 | *+
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| 3 | * Name:
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| 4 | * palMapqk
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| 5 |
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| 6 | * Purpose:
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| 7 | * Quick mean to apparent place
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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 | * void palMapqk ( double rm, double dm, double pr, double pd,
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| 17 | * double px, double rv, double amprms[21],
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| 18 | * double *ra, double *da );
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| 19 |
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| 20 | * Arguments:
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| 21 | * rm = double (Given)
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| 22 | * Mean RA (radians)
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| 23 | * dm = double (Given)
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| 24 | * Mean declination (radians)
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| 25 | * pr = double (Given)
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| 26 | * RA proper motion, changes per Julian year (radians)
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| 27 | * pd = double (Given)
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| 28 | * Dec proper motion, changes per Julian year (radians)
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| 29 | * px = double (Given)
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| 30 | * Parallax (arcsec)
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| 31 | * rv = double (Given)
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| 32 | * Radial velocity (km/s, +ve if receding)
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| 33 | * amprms = double [21] (Given)
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| 34 | * Star-independent mean-to-apparent parameters (see palMappa).
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| 35 | * ra = double * (Returned)
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| 36 | * Apparent RA (radians)
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| 37 | * dec = double * (Returned)
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| 38 | * Apparent dec (radians)
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| 39 |
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| 40 | * Description:
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| 41 | * Quick mean to apparent place: transform a star RA,Dec from
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| 42 | * mean place to geocentric apparent place, given the
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| 43 | * star-independent parameters.
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| 44 | *
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| 45 | * Use of this routine is appropriate when efficiency is important
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| 46 | * and where many star positions, all referred to the same equator
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| 47 | * and equinox, are to be transformed for one epoch. The
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| 48 | * star-independent parameters can be obtained by calling the
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| 49 | * palMappa routine.
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| 50 | *
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| 51 | * If the parallax and proper motions are zero the palMapqkz
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| 52 | * routine can be used instead.
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| 53 |
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| 54 | * Authors:
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| 55 | * PTW: Patrick T. Wallace
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| 56 | * TIMJ: Tim Jenness (JAC, Hawaii)
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| 57 | * {enter_new_authors_here}
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| 58 |
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| 59 | * Notes:
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| 60 | * - The reference frames and timescales used are post IAU 2006.
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| 61 |
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| 62 | * History:
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| 63 | * 2012-03-01 (TIMJ):
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| 64 | * Initial version with documentation from SLA/F
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| 65 | * Adapted with permission from the Fortran SLALIB library.
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| 66 | * {enter_further_changes_here}
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| 67 |
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| 68 | * Copyright:
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| 69 | * Copyright (C) 2000 Rutherford Appleton Laboratory
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| 70 | * Copyright (C) 2012 Science and Technology Facilities Council.
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| 71 | * All Rights Reserved.
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| 72 |
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| 73 | * Licence:
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| 74 | * This program is free software; you can redistribute it and/or
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| 75 | * modify it under the terms of the GNU General Public License as
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| 76 | * published by the Free Software Foundation; either version 3 of
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| 77 | * the License, or (at your option) any later version.
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| 78 | *
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| 79 | * This program is distributed in the hope that it will be
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| 80 | * useful, but WITHOUT ANY WARRANTY; without even the implied
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| 81 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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| 82 | * PURPOSE. See the GNU General Public License for more details.
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| 83 | *
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| 84 | * You should have received a copy of the GNU General Public License
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| 85 | * along with this program; if not, write to the Free Software
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| 86 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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| 87 | * MA 02110-1301, USA.
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| 88 |
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| 89 | * Bugs:
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| 90 | * {note_any_bugs_here}
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| 91 | *-
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| 92 | */
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| 93 |
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| 94 | #include "pal.h"
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| 95 | #include "palmac.h"
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| 96 | #include "pal1sofa.h"
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| 97 |
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| 98 | void palMapqk ( double rm, double dm, double pr, double pd,
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| 99 | double px, double rv, double amprms[21],
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| 100 | double *ra, double *da ) {
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| 101 |
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| 102 | /* local constants */
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| 103 | const double VF = 0.21094502; /* Km/s to AU/year */
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| 104 |
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| 105 | /* Local Variables: */
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| 106 | int i;
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| 107 | double ab1, abv[3], p[3], w, p1dv, p2[3], p3[3];
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| 108 | double pmt, gr2e, eb[3], q[3], pxr, em[3];
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| 109 | double pde, pdep1, p1[3], ehn[3], pn[3];
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| 110 |
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| 111 | /* Unpack scalar and vector parameters. */
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| 112 | pmt = amprms[0];
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| 113 | gr2e = amprms[7];
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| 114 | ab1 = amprms[11];
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| 115 | for( i = 0; i < 3; i++ ) {
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| 116 | eb[i] = amprms[i+1];
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| 117 | ehn[i] = amprms[i+4];
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| 118 | abv[i] = amprms[i+8];
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| 119 | }
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| 120 |
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| 121 | /* Spherical to x,y,z. */
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| 122 | eraS2c( rm, dm, q);
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| 123 |
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| 124 | /* Space motion (radians per year) */
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| 125 | pxr = px * PAL__DAS2R;
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| 126 | w = VF * rv * pxr;
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| 127 | em[0] = -pr * q[1] - pd * cos(rm) * sin(dm) + w * q[0];
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| 128 | em[1] = pr * q[0] - pd * sin(rm) * sin(dm) + w * q[1];
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| 129 | em[2] = pd * cos(dm) + w * q[2];
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| 130 |
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| 131 | /* Geocentric direction of star (normalised) */
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| 132 | for( i = 0; i < 3; i++ ) {
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| 133 | p[i] = q[i] + pmt * em[i] - pxr * eb[i];
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| 134 | }
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| 135 | eraPn( p, &w, pn );
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| 136 |
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| 137 | /* Light deflection (restrained within the Sun's disc) */
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| 138 | pde = eraPdp( pn, ehn );
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| 139 | pdep1 = pde + 1.0;
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| 140 | w = gr2e / ( pdep1 > 1.0e-5 ? pdep1 : 1.0e-5 );
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| 141 | for( i = 0; i < 3; i++) {
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| 142 | p1[i] = pn[i] + w * ( ehn[i] - pde * pn[i] );
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| 143 | }
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| 144 |
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| 145 | /* Aberration (normalisation omitted). */
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| 146 | p1dv = eraPdp( p, abv );
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| 147 | w = 1.0 + p1dv / ( ab1 + 1.0 );
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| 148 | for( i = 0; i < 3; i++ ) {
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| 149 | p2[i] = ( ab1 * p1[i] ) + ( w * abv[i] );
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| 150 | }
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| 151 |
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| 152 | /* Precession and nutation. */
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| 153 | eraRxp( (double(*)[3]) &rms[12], p2, p3 );
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| 154 |
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| 155 | /* Geocentric apparent RA,dec. */
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| 156 | eraC2s( p3, ra, da );
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| 157 | *ra = eraAnp( *ra );
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| 158 |
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| 159 | }
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