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#include "erfa.h"
void eraAtic13(double ri, double di, double date1, double date2,
double *rc, double *dc, double *eo)
/*
** - - - - - - - - - -
** e r a A t i c 1 3
** - - - - - - - - - -
**
** Transform star RA,Dec from geocentric CIRS to ICRS astrometric.
**
** Given:
** ri,di double CIRS geocentric RA,Dec (radians)
** date1 double TDB as a 2-part...
** date2 double ...Julian Date (Note 1)
**
** Returned:
** rc,dc double ICRS astrometric RA,Dec (radians)
** eo double equation of the origins (ERA-GST, Note 4)
**
** Notes:
**
** 1) The TDB date date1+date2 is a Julian Date, apportioned in any
** convenient way between the two arguments. For example,
** JD(TDB)=2450123.7 could be expressed in any of these ways, among
** others:
**
** date1 date2
**
** 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. For most
** applications of this function the choice will not be at all
** critical.
**
** TT can be used instead of TDB without any significant impact on
** accuracy.
**
** 2) Iterative techniques are used for the aberration and light
** deflection corrections so that the functions eraAtic13 (or
** eraAticq) and eraAtci13 (or eraAtciq) are accurate inverses;
** even at the edge of the Sun's disk the discrepancy is only about
** 1 nanoarcsecond.
**
** 3) The available accuracy is better than 1 milliarcsecond, limited
** mainly by the precession-nutation model that is used, namely
** IAU 2000A/2006. Very close to solar system bodies, additional
** errors of up to several milliarcseconds can occur because of
** unmodeled light deflection; however, the Sun's contribution is
** taken into account, to first order. The accuracy limitations of
** the ERFA function eraEpv00 (used to compute Earth position and
** velocity) can contribute aberration errors of up to
** 5 microarcseconds. Light deflection at the Sun's limb is
** uncertain at the 0.4 mas level.
**
** 4) Should the transformation to (equinox based) J2000.0 mean place
** be required rather than (CIO based) ICRS coordinates, subtract the
** equation of the origins from the returned right ascension:
** RA = RI - EO. (The eraAnp function can then be applied, as
** required, to keep the result in the conventional 0-2pi range.)
**
** Called:
** eraApci13 astrometry parameters, ICRS-CIRS, 2013
** eraAticq quick CIRS to ICRS astrometric
**
** Copyright (C) 2013-2016, NumFOCUS Foundation.
** Derived, with permission, from the SOFA library. See notes at end of file.
*/
{
/* Star-independent astrometry parameters */
eraASTROM astrom;
/* Star-independent astrometry parameters. */
eraApci13(date1, date2, &astrom, eo);
/* CIRS to ICRS astrometric. */
eraAticq(ri, di, &astrom, rc, dc);
/* 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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