SUBROUTINE iau_SEPS ( AL, AP, BL, BP, S )
*+
*  - - - - - - - - -
*   i a u _ S E P S
*  - - - - - - - - -
*
*  Angular separation between two sets of spherical coordinates.
*
*  This routine is part of the International Astronomical Union's
*  SOFA (Standards of Fundamental Astronomy) software collection.
*
*  Status:  vector/matrix support routine.
*
*  Given:
*     AL       d         first longitude (radians)
*     AP       d         first latitude (radians)
*     BL       d         second longitude (radians)
*     BP       d         second latitude (radians)
*
*  Returned:
*     S        d         angular separation (radians)
*
*  Called:
*     iau_S2C      spherical coordinates to unit vector
*     iau_SEPP     angular separation between two p-vectors
*
*  This revision:  2006 November 13
*
*  Copyright (C) 2008 IAU SOFA Review Board.  See notes at end.
*
*-----------------------------------------------------------------------

      IMPLICIT NONE

      DOUBLE PRECISION AL, AP, BL, BP, S

      DOUBLE PRECISION AC(3), BC(3)

* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

*  Spherical to Cartesian.
      CALL iau_S2C ( AL, AP, AC )
      CALL iau_S2C ( BL, BP, BC )

*  Angle between the vectors.
      CALL iau_SEPP ( AC, BC, S )

*  Finished.

*+-----------------------------------------------------------------------
*
*  Copyright (C) 2008
*  Standards Of Fundamental Astronomy Review Board
*  of the International Astronomical Union.
*
*  =====================
*  SOFA Software License
*  =====================
*
*  NOTICE TO USER:
*
*  BY USING THIS SOFTWARE YOU ACCEPT THE FOLLOWING TERMS AND CONDITIONS
*  WHICH APPLY TO ITS USE.
*
*  1. The Software is owned by the IAU SOFA Review Board ("the Board").
*
*  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 adapt the SOFA software and its 
*     algorithms for your own purposes and you may copy and distribute
*     a resulting "derived work" to others on a world-wide, royalty-free 
*     basis, provided that the derived work complies 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 contain
*        software provided by SOFA or software that has been distributed
*        by or endorsed by SOFA.
*
*     b) The source code of your derived work must contain descriptions
*        of how the derived work is based upon and/or differs from the
*        original SOFA software.
*
*     c) The name(s) of all routine(s) that you distribute shall differ
*        from the SOFA names, even when the SOFA content has not been
*        otherwise changed.
*
*     d) The routine-naming prefix "iau" shall not be used.
*
*     e) 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.
*
*     f) 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.
*
*  4. In any published work or commercial products which includes
*     results achieved by using the SOFA software, you shall acknowledge
*     that the SOFA software was used in obtaining those results.
*
*  5. You shall not cause the SOFA software to be brought into
*     disrepute, either by misuse, or use for inappropriate tasks, or by
*     inappropriate modification.
*
*  6. The SOFA software is provided "as is" and the Board makes no 
*     warranty as to its use or performance.   The Board does not and 
*     cannot warrant the performance or results which the user may obtain 
*     by using the SOFA software.  The Board 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 the Board be liable to the user for any consequential,
*     incidental, or special damages, including any lost profits or lost
*     savings, even if a Board representative has been advised of such
*     damages, or for any claim by any third party.
*
*  7. 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.
*
*  Correspondence concerning SOFA software should be addressed as
*  follows:
*
*     Internet email: sofa@rl.ac.uk
*     Postal address: IAU SOFA Center
*                     Rutherford Appleton Laboratory
*                     Chilton, Didcot, Oxon OX11 0QX
*                     United Kingdom
*
*-----------------------------------------------------------------------

      END