| 1 | /*
|
|---|
| 2 | *+
|
|---|
| 3 | * Name:
|
|---|
| 4 | * palAmpqk
|
|---|
| 5 |
|
|---|
| 6 | * Purpose:
|
|---|
| 7 | * Convert star RA,Dec from geocentric apparent to mean place.
|
|---|
| 8 |
|
|---|
| 9 | * Language:
|
|---|
| 10 | * Starlink ANSI C
|
|---|
| 11 |
|
|---|
| 12 | * Type of Module:
|
|---|
| 13 | * Library routine
|
|---|
| 14 |
|
|---|
| 15 | * Invocation:
|
|---|
| 16 | * void palAmpqk ( double ra, double da, double amprms[21],
|
|---|
| 17 | * double *rm, double *dm )
|
|---|
| 18 |
|
|---|
| 19 | * Arguments:
|
|---|
| 20 | * ra = double (Given)
|
|---|
| 21 | * Apparent RA (radians).
|
|---|
| 22 | * da = double (Given)
|
|---|
| 23 | * Apparent Dec (radians).
|
|---|
| 24 | * amprms = double[21] (Given)
|
|---|
| 25 | * Star-independent mean-to-apparent parameters (see palMappa):
|
|---|
| 26 | * (0) time interval for proper motion (Julian years)
|
|---|
| 27 | * (1-3) barycentric position of the Earth (AU)
|
|---|
| 28 | * (4-6) not used
|
|---|
| 29 | * (7) not used
|
|---|
| 30 | * (8-10) abv: barycentric Earth velocity in units of c
|
|---|
| 31 | * (11) sqrt(1-v*v) where v=modulus(abv)
|
|---|
| 32 | * (12-20) precession/nutation (3,3) matrix
|
|---|
| 33 | * rm = double (Returned)
|
|---|
| 34 | * Mean RA (radians).
|
|---|
| 35 | * dm = double (Returned)
|
|---|
| 36 | * Mean Dec (radians).
|
|---|
| 37 |
|
|---|
| 38 | * Description:
|
|---|
| 39 | * Convert star RA,Dec from geocentric apparent to mean place. The "mean"
|
|---|
| 40 | * coordinate system is in fact close to ICRS. Use of this function
|
|---|
| 41 | * is appropriate when efficiency is important and where many star
|
|---|
| 42 | * positions are all to be transformed for one epoch and equinox. The
|
|---|
| 43 | * star-independent parameters can be obtained by calling the palMappa
|
|---|
| 44 | * function.
|
|---|
| 45 |
|
|---|
| 46 | * Authors:
|
|---|
| 47 | * PTW: Pat Wallace (STFC)
|
|---|
| 48 | * {enter_new_authors_here}
|
|---|
| 49 |
|
|---|
| 50 | * History:
|
|---|
| 51 | * 2012-02-13 (PTW):
|
|---|
| 52 | * Initial version.
|
|---|
| 53 | * Adapted with permission from the Fortran SLALIB library.
|
|---|
| 54 | * {enter_further_changes_here}
|
|---|
| 55 |
|
|---|
| 56 | * Copyright:
|
|---|
| 57 | * Copyright (C) 2000 Rutherford Appleton Laboratory
|
|---|
| 58 | * Copyright (C) 2012 Science and Technology Facilities Council.
|
|---|
| 59 | * All Rights Reserved.
|
|---|
| 60 |
|
|---|
| 61 | * Licence:
|
|---|
| 62 | * This program is free software: you can redistribute it and/or
|
|---|
| 63 | * modify it under the terms of the GNU Lesser General Public
|
|---|
| 64 | * License as published by the Free Software Foundation, either
|
|---|
| 65 | * version 3 of the License, or (at your option) any later
|
|---|
| 66 | * version.
|
|---|
| 67 | *
|
|---|
| 68 | * This program is distributed in the hope that it will be useful,
|
|---|
| 69 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|---|
| 70 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|---|
| 71 | * GNU Lesser General Public License for more details.
|
|---|
| 72 | *
|
|---|
| 73 | * You should have received a copy of the GNU Lesser General
|
|---|
| 74 | * License along with this program. If not, see
|
|---|
| 75 | * <http://www.gnu.org/licenses/>.
|
|---|
| 76 |
|
|---|
| 77 | * Bugs:
|
|---|
| 78 | * {note_any_bugs_here}
|
|---|
| 79 | *-
|
|---|
| 80 | */
|
|---|
| 81 |
|
|---|
| 82 | #include "pal.h"
|
|---|
| 83 | #include "pal1sofa.h"
|
|---|
| 84 |
|
|---|
| 85 | void palAmpqk ( double ra, double da, double amprms[21], double *rm,
|
|---|
| 86 | double *dm ){
|
|---|
| 87 |
|
|---|
| 88 | /* Local Variables: */
|
|---|
| 89 | double ab1; /* sqrt(1-v*v) where v=modulus of Earth vel */
|
|---|
| 90 | double abv[3]; /* Earth velocity wrt SSB (c, FK5) */
|
|---|
| 91 | double p1[3], p2[3], p3[3]; /* work vectors */
|
|---|
| 92 | double ab1p1, p1dv, p1dvp1, w;
|
|---|
| 93 | int i, j;
|
|---|
| 94 |
|
|---|
| 95 | /* Unpack some of the parameters */
|
|---|
| 96 | ab1 = amprms[11];
|
|---|
| 97 | for( i = 0; i < 3; i++ ) {
|
|---|
| 98 | abv[i] = amprms[i + 8];
|
|---|
| 99 | }
|
|---|
| 100 |
|
|---|
| 101 | /* Apparent RA,Dec to Cartesian */
|
|---|
| 102 | eraS2c( ra, da, p3 );
|
|---|
| 103 |
|
|---|
| 104 | /* Precession and nutation */
|
|---|
| 105 | eraTrxp( (double(*)[3]) &rms[12], p3, p2 );
|
|---|
| 106 |
|
|---|
| 107 | /* Aberration */
|
|---|
| 108 | ab1p1 = ab1 + 1.0;
|
|---|
| 109 | for( i = 0; i < 3; i++ ) {
|
|---|
| 110 | p1[i] = p2[i];
|
|---|
| 111 | }
|
|---|
| 112 | for( j = 0; j < 2; j++ ) {
|
|---|
| 113 | p1dv = eraPdp( p1, abv );
|
|---|
| 114 | p1dvp1 = 1.0 + p1dv;
|
|---|
| 115 | w = 1.0 + p1dv / ab1p1;
|
|---|
| 116 | for( i = 0; i < 3; i++ ) {
|
|---|
| 117 | p1[i] = ( p1dvp1 * p2[i] - w * abv[i] ) / ab1;
|
|---|
| 118 | }
|
|---|
| 119 | eraPn( p1, &w, p3 );
|
|---|
| 120 | for( i = 0; i < 3; i++ ) {
|
|---|
| 121 | p1[i] = p3[i];
|
|---|
| 122 | }
|
|---|
| 123 | }
|
|---|
| 124 |
|
|---|
| 125 | /* Mean RA,Dec */
|
|---|
| 126 | eraC2s( p1, rm, dm );
|
|---|
| 127 | *rm = eraAnp( *rm );
|
|---|
| 128 | }
|
|---|
