| 1 | /*
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| 2 | *+
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| 3 | * Name:
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| 4 | * palMap
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| 5 |
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| 6 | * Purpose:
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| 7 | * Convert star RA,Dec from mean place to geocentric apparent
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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 palMap( double rm, double dm, double pr, double pd,
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| 17 | * double px, double rv, double eq, double date,
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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 | * eq = double (Given)
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| 34 | * Epoch and equinox of star data (Julian)
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| 35 | * date = double (Given)
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| 36 | * TDB for apparent place (JD-2400000.5)
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| 37 | * ra = double * (Returned)
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| 38 | * Apparent RA (radians)
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| 39 | * dec = double * (Returned)
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| 40 | * Apparent dec (radians)
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| 41 |
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| 42 | * Description:
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| 43 | * Convert star RA,Dec from mean place to geocentric apparent.
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| 44 |
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| 45 | * Authors:
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| 46 | * PTW: Patrick T. Wallace
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| 47 | * TIMJ: Tim Jenness (JAC, Hawaii)
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| 48 | * {enter_new_authors_here}
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| 49 |
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| 50 | * Notes:
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| 51 | * - Calls palMappa and palMapqk
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| 52 |
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| 53 | * - The reference systems and timescales used are IAU 2006.
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| 54 |
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| 55 | * - EQ is the Julian epoch specifying both the reference frame and
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| 56 | * the epoch of the position - usually 2000. For positions where
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| 57 | * the epoch and equinox are different, use the routine palPm to
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| 58 | * apply proper motion corrections before using this routine.
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| 59 | *
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| 60 | * - The distinction between the required TDB and TT is always
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| 61 | * negligible. Moreover, for all but the most critical
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| 62 | * applications UTC is adequate.
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| 63 | *
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| 64 | * - The proper motions in RA are dRA/dt rather than cos(Dec)*dRA/dt.
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| 65 | *
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| 66 | * - This routine may be wasteful for some applications because it
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| 67 | * recomputes the Earth position/velocity and the precession-
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| 68 | * nutation matrix each time, and because it allows for parallax
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| 69 | * and proper motion. Where multiple transformations are to be
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| 70 | * carried out for one epoch, a faster method is to call the
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| 71 | * palMappa routine once and then either the palMapqk routine
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| 72 | * (which includes parallax and proper motion) or palMapqkz (which
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| 73 | * assumes zero parallax and proper motion).
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| 74 | *
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| 75 | * - The accuracy is sub-milliarcsecond, limited by the
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| 76 | * precession-nutation model (see palPrenut for details).
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| 77 | *
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| 78 | * - The accuracy is further limited by the routine palEvp, called
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| 79 | * by palMappa, which computes the Earth position and velocity.
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| 80 | * See eraEpv00 for details on that calculation.
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| 81 |
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| 82 | * History:
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| 83 | * 2012-03-01 (TIMJ):
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| 84 | * Initial version
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| 85 | * Adapted with permission from the Fortran SLALIB library.
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| 86 | * {enter_further_changes_here}
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| 87 |
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| 88 | * Copyright:
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| 89 | * Copyright (C) 2001 Rutherford Appleton Laboratory
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| 90 | * Copyright (C) 2012 Science and Technology Facilities Council.
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| 91 | * All Rights Reserved.
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| 92 |
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| 93 | * Licence:
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| 94 | * This program is free software; you can redistribute it and/or
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| 95 | * modify it under the terms of the GNU General Public License as
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| 96 | * published by the Free Software Foundation; either version 3 of
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| 97 | * the License, or (at your option) any later version.
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| 98 | *
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| 99 | * This program is distributed in the hope that it will be
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| 100 | * useful, but WITHOUT ANY WARRANTY; without even the implied
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| 101 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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| 102 | * PURPOSE. See the GNU General Public License for more details.
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| 103 | *
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| 104 | * You should have received a copy of the GNU General Public License
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| 105 | * along with this program; if not, write to the Free Software
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| 106 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
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| 107 | * USA.
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| 108 |
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| 109 | * Bugs:
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| 110 | * {note_any_bugs_here}
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| 111 | *-
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| 112 | */
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| 113 |
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| 114 | #include "pal.h"
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| 115 |
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| 116 | void palMap( double rm, double dm, double pr, double pd,
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| 117 | double px, double rv, double eq, double date,
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| 118 | double *ra, double *da ) {
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| 119 |
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| 120 | double amprms[21];
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| 121 |
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| 122 | /* Star independent parameters */
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| 123 | palMappa( eq, date, amprms );
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| 124 |
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| 125 | /* Mean to apparent */
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| 126 | palMapqk( rm, dm, pr, pd, px, rv, amprms, ra, da );
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| 127 |
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| 128 | }
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