SUBROUTINE sla_PLANEL (DATE, JFORM, EPOCH, ORBINC, ANODE, PERIH,
     :                       AORQ, E, AORL, DM, PV, JSTAT)
*+
*     - - - - - - -
*      P L A N E L
*     - - - - - - -
*
*  Heliocentric position and velocity of a planet, asteroid or comet,
*  starting from orbital elements.
*
*  Given:
*     DATE      d      date, Modified Julian Date (JD - 2400000.5)
*     JFORM     i      choice of element set (1-3; Note 3)
*     EPOCH     d      epoch of elements (TT MJD)
*     ORBINC    d      inclination (radians)
*     ANODE     d      longitude of the ascending node (radians)
*     PERIH     d      longitude or argument of perihelion (radians)
*     AORQ      d      mean distance or perihelion distance (AU)
*     E         d      eccentricity
*     AORL      d      mean anomaly or longitude (radians, JFORM=1,2 only)
*     DM        d      daily motion (radians, JFORM=1 only)
*
*  Returned:
*     PV        d(6)   heliocentric x,y,z,xdot,ydot,zdot of date,
*                                       J2000 equatorial triad (AU,AU/s)
*     JSTAT     i      status:  0 = OK
*                              -1 = illegal JFORM
*                              -2 = illegal E
*                              -3 = illegal AORQ
*                              -4 = illegal DM
*                              -5 = numerical error
*
*  Called:  sla_EL2UE, sla_UE2PV
*
*  Notes
*
*  1  DATE is the instant for which the prediction is required.  It is
*     in the TT timescale (formerly Ephemeris Time, ET) and is a
*     Modified Julian Date (JD-2400000.5).
*
*  2  The elements are with respect to the J2000 ecliptic and equinox.
*
*  3  Three different element-format options are available:
*
*     Option JFORM=1, suitable for the major planets:
*
*     EPOCH  = epoch of elements (TT MJD)
*     ORBINC = inclination i (radians)
*     ANODE  = longitude of the ascending node, big omega (radians)
*     PERIH  = longitude of perihelion, curly pi (radians)
*     AORQ   = mean distance, a (AU)
*     E      = eccentricity, e (range 0 to <1)
*     AORL   = mean longitude L (radians)
*     DM     = daily motion (radians)
*
*     Option JFORM=2, suitable for minor planets:
*
*     EPOCH  = epoch of elements (TT MJD)
*     ORBINC = inclination i (radians)
*     ANODE  = longitude of the ascending node, big omega (radians)
*     PERIH  = argument of perihelion, little omega (radians)
*     AORQ   = mean distance, a (AU)
*     E      = eccentricity, e (range 0 to <1)
*     AORL   = mean anomaly M (radians)
*
*     Option JFORM=3, suitable for comets:
*
*     EPOCH  = epoch of perihelion (TT MJD)
*     ORBINC = inclination i (radians)
*     ANODE  = longitude of the ascending node, big omega (radians)
*     PERIH  = argument of perihelion, little omega (radians)
*     AORQ   = perihelion distance, q (AU)
*     E      = eccentricity, e (range 0 to 10)
*
*  4  Unused elements (DM for JFORM=2, AORL and DM for JFORM=3) are
*     not accessed.
*
*  5  The reference frame for the result is with respect to the mean
*     equator and equinox of epoch J2000.
*
*  6  The algorithm was originally adapted from the EPHSLA program of
*     D.H.P.Jones (private communication, 1996).  The method is based
*     on Stumpff's Universal Variables.
*
*  Reference:  Everhart, E. & Pitkin, E.T., Am.J.Phys. 51, 712, 1983.
*
*  P.T.Wallace   Starlink   18 March 1999
*
*  Copyright (C) 1999 Rutherford Appleton Laboratory
*-

      IMPLICIT NONE

      DOUBLE PRECISION DATE
      INTEGER JFORM
      DOUBLE PRECISION EPOCH,ORBINC,ANODE,PERIH,AORQ,E,AORL,DM,PV(6)
      INTEGER JSTAT

      DOUBLE PRECISION U(13)
      INTEGER J



*  Validate elements and convert to "universal variables" parameters.
      CALL sla_EL2UE(DATE,JFORM,
     :               EPOCH,ORBINC,ANODE,PERIH,AORQ,E,AORL,DM,U,J)

*  Determine the position and velocity.
      IF (J.EQ.0) THEN
         CALL sla_UE2PV(DATE,U,PV,J)
         IF (J.NE.0) J=-5
      END IF

*  Wrap up.
      JSTAT = J

      END