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#include "erfa.h"
int eraPmsafe(double ra1, double dec1, double pmr1, double pmd1,
double px1, double rv1,
double ep1a, double ep1b, double ep2a, double ep2b,
double *ra2, double *dec2, double *pmr2, double *pmd2,
double *px2, double *rv2)
/*
** - - - - - - - - - -
** e r a P m s a f e
** - - - - - - - - - -
**
** Star proper motion: update star catalog data for space motion, with
** special handling to handle the zero parallax case.
**
** Given:
** ra1 double right ascension (radians), before
** dec1 double declination (radians), before
** pmr1 double RA proper motion (radians/year), before
** pmd1 double Dec proper motion (radians/year), before
** px1 double parallax (arcseconds), before
** rv1 double radial velocity (km/s, +ve = receding), before
** ep1a double "before" epoch, part A (Note 1)
** ep1b double "before" epoch, part B (Note 1)
** ep2a double "after" epoch, part A (Note 1)
** ep2b double "after" epoch, part B (Note 1)
**
** Returned:
** ra2 double right ascension (radians), after
** dec2 double declination (radians), after
** pmr2 double RA proper motion (radians/year), after
** pmd2 double Dec proper motion (radians/year), after
** px2 double parallax (arcseconds), after
** rv2 double radial velocity (km/s, +ve = receding), after
**
** Returned (function value):
** int status:
** -1 = system error (should not occur)
** 0 = no warnings or errors
** 1 = distance overridden (Note 6)
** 2 = excessive velocity (Note 7)
** 4 = solution didn't converge (Note 8)
** else = binary logical OR of the above warnings
**
** Notes:
**
** 1) The starting and ending TDB epochs ep1a+ep1b and ep2a+ep2b are
** Julian Dates, apportioned in any convenient way between the two
** parts (A and B). For example, JD(TDB)=2450123.7 could be
** expressed in any of these ways, among others:
**
** epNa epNb
**
** 2450123.7 0.0 (JD method)
** 2451545.0 -1421.3 (J2000 method)
** 2400000.5 50123.2 (MJD method)
** 2450123.5 0.2 (date & time method)
**
** The JD method is the most natural and convenient to use in cases
** where the loss of several decimal digits of resolution is
** acceptable. The J2000 method is best matched to the way the
** argument is handled internally and will deliver the optimum
** resolution. The MJD method and the date & time methods are both
** good compromises between resolution and convenience.
**
** 2) In accordance with normal star-catalog conventions, the object's
** right ascension and declination are freed from the effects of
** secular aberration. The frame, which is aligned to the catalog
** equator and equinox, is Lorentzian and centered on the SSB.
**
** The proper motions are the rate of change of the right ascension
** and declination at the catalog epoch and are in radians per TDB
** Julian year.
**
** The parallax and radial velocity are in the same frame.
**
** 3) Care is needed with units. The star coordinates are in radians
** and the proper motions in radians per Julian year, but the
** parallax is in arcseconds.
**
** 4) The RA proper motion is in terms of coordinate angle, not true
** angle. If the catalog uses arcseconds for both RA and Dec proper
** motions, the RA proper motion will need to be divided by cos(Dec)
** before use.
**
** 5) Straight-line motion at constant speed, in the inertial frame, is
** assumed.
**
** 6) An extremely small (or zero or negative) parallax is overridden
** to ensure that the object is at a finite but very large distance,
** but not so large that the proper motion is equivalent to a large
** but safe speed (about 0.1c using the chosen constant). A warning
** status of 1 is added to the status if this action has been taken.
**
** 7) If the space velocity is a significant fraction of c (see the
** constant VMAX in the function eraStarpv), it is arbitrarily set
** to zero. When this action occurs, 2 is added to the status.
**
** 8) The relativistic adjustment carried out in the eraStarpv function
** involves an iterative calculation. If the process fails to
** converge within a set number of iterations, 4 is added to the
** status.
**
** Called:
** eraSeps angle between two points
** eraStarpm update star catalog data for space motion
**
** Copyright (C) 2013-2016, NumFOCUS Foundation.
** Derived, with permission, from the SOFA library. See notes at end of file.
*/
{
/* Minimum allowed parallax (arcsec) */
const double PXMIN = 5e-7;
/* Factor giving maximum allowed transverse speed of about 1% c */
const double F = 326.0;
int jpx, j;
double pm, px1a;
/* Proper motion in one year (radians). */
pm = eraSeps(ra1, dec1, ra1+pmr1, dec1+pmd1);
/* Override the parallax to reduce the chances of a warning status. */
jpx = 0;
px1a = px1;
pm *= F;
if (px1a < pm) {jpx = 1; px1a = pm;}
if (px1a < PXMIN) {jpx = 1; px1a = PXMIN;}
/* Carry out the transformation using the modified parallax. */
j = eraStarpm(ra1, dec1, pmr1, pmd1, px1a, rv1,
ep1a, ep1b, ep2a, ep2b,
ra2, dec2, pmr2, pmd2, px2, rv2);
/* Revise and return the status. */
if ( !(j%2) ) j += jpx;
return j;
/* Finished. */
}
/*----------------------------------------------------------------------
**
**
** Copyright (C) 2013-2016, NumFOCUS Foundation.
** All rights reserved.
**
** This library is derived, with permission, from the International
** Astronomical Union's "Standards of Fundamental Astronomy" library,
** available from http://www.iausofa.org.
**
** The ERFA version is intended to retain identical functionality to
** the SOFA library, but made distinct through different function and
** file names, as set out in the SOFA license conditions. The SOFA
** original has a role as a reference standard for the IAU and IERS,
** and consequently redistribution is permitted only in its unaltered
** state. The ERFA version is not subject to this restriction and
** therefore can be included in distributions which do not support the
** concept of "read only" software.
**
** Although the intent is to replicate the SOFA API (other than
** replacement of prefix names) and results (with the exception of
** bugs; any that are discovered will be fixed), SOFA is not
** responsible for any errors found in this version of the library.
**
** If you wish to acknowledge the SOFA heritage, please acknowledge
** that you are using a library derived from SOFA, rather than SOFA
** itself.
**
**
** TERMS AND CONDITIONS
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1 Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
**
** 2 Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
**
** 3 Neither the name of the Standards Of Fundamental Astronomy Board,
** the International Astronomical Union nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
** FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
** COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
** BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
** LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
** CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
** ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
** POSSIBILITY OF SUCH DAMAGE.
**
*/
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