#include "sofa.h"

void iauAtic13(double ri, double di, double date1, double date2,
               double *rc, double *dc, double *eo)
/*
**  - - - - - - - - - -
**   i a u A t i c 1 3
**  - - - - - - - - - -
**
**  Transform star RA,Dec from geocentric CIRS to ICRS astrometric.
**
**  This function is part of the International Astronomical Union's
**  SOFA (Standards of Fundamental Astronomy) software collection.
**
**  Status:  support function.
**
**  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 iauAtic13 (or
**     iauAticq) and iauAtci13 (or iauAtciq) 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 SOFA function iauEpv00 (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 iauAnp function can then be applied, as
**     required, to keep the result in the conventional 0-2pi range.)
**
**  Called:
**     iauApci13    astrometry parameters, ICRS-CIRS, 2013
**     iauAticq     quick CIRS to ICRS astrometric
**
**  This revision:   2013 October 9
**
**  SOFA release 2017-04-20
**
**  Copyright (C) 2017 IAU SOFA Board.  See notes at end.
*/
{
/* Star-independent astrometry parameters */
   iauASTROM astrom;


/* Star-independent astrometry parameters. */
   iauApci13(date1, date2, &astrom, eo);

/* CIRS to ICRS astrometric. */
   iauAticq(ri, di, &astrom, rc, dc);

/* Finished. */

/*----------------------------------------------------------------------
**
**  Copyright (C) 2017
**  Standards Of Fundamental Astronomy Board
**  of the International Astronomical Union.
**
**  =====================
**  SOFA Software License
**  =====================
**
**  NOTICE TO USER:
**
**  BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING SIX TERMS AND
**  CONDITIONS WHICH APPLY TO ITS USE.
**
**  1. The Software is owned by the IAU SOFA Board ("SOFA").
**
**  2. Permission is granted to anyone to use the SOFA software for any
**     purpose, including commercial applications, free of charge and
**     without payment of royalties, subject to the conditions and
**     restrictions listed below.
**
**  3. You (the user) may copy and distribute SOFA source code to others,
**     and use and adapt its code and algorithms in your own software,
**     on a world-wide, royalty-free basis.  That portion of your
**     distribution that does not consist of intact and unchanged copies
**     of SOFA source code files is a "derived work" that must comply
**     with the following requirements:
**
**     a) Your work shall be marked or carry a statement that it
**        (i) uses routines and computations derived by you from
**        software provided by SOFA under license to you; and
**        (ii) does not itself constitute software provided by and/or
**        endorsed by SOFA.
**
**     b) The source code of your derived work must contain descriptions
**        of how the derived work is based upon, contains and/or differs
**        from the original SOFA software.
**
**     c) The names of all routines in your derived work shall not
**        include the prefix "iau" or "sofa" or trivial modifications
**        thereof such as changes of case.
**
**     d) The origin of the SOFA components of your derived work must
**        not be misrepresented;  you must not claim that you wrote the
**        original software, nor file a patent application for SOFA
**        software or algorithms embedded in the SOFA software.
**
**     e) These requirements must be reproduced intact in any source
**        distribution and shall apply to anyone to whom you have
**        granted a further right to modify the source code of your
**        derived work.
**
**     Note that, as originally distributed, the SOFA software is
**     intended to be a definitive implementation of the IAU standards,
**     and consequently third-party modifications are discouraged.  All
**     variations, no matter how minor, must be explicitly marked as
**     such, as explained above.
**
**  4. You shall not cause the SOFA software to be brought into
**     disrepute, either by misuse, or use for inappropriate tasks, or
**     by inappropriate modification.
**
**  5. The SOFA software is provided "as is" and SOFA makes no warranty
**     as to its use or performance.   SOFA does not and cannot warrant
**     the performance or results which the user may obtain by using the
**     SOFA software.  SOFA makes no warranties, express or implied, as
**     to non-infringement of third party rights, merchantability, or
**     fitness for any particular purpose.  In no event will SOFA be
**     liable to the user for any consequential, incidental, or special
**     damages, including any lost profits or lost savings, even if a
**     SOFA representative has been advised of such damages, or for any
**     claim by any third party.
**
**  6. The provision of any version of the SOFA software under the terms
**     and conditions specified herein does not imply that future
**     versions will also be made available under the same terms and
**     conditions.
*
**  In any published work or commercial product which uses the SOFA
**  software directly, acknowledgement (see www.iausofa.org) is
**  appreciated.
**
**  Correspondence concerning SOFA software should be addressed as
**  follows:
**
**      By email:  sofa@ukho.gov.uk
**      By post:   IAU SOFA Center
**                 HM Nautical Almanac Office
**                 UK Hydrographic Office
**                 Admiralty Way, Taunton
**                 Somerset, TA1 2DN
**                 United Kingdom
**
**--------------------------------------------------------------------*/

}