.help plante Jun99 "Slalib Package"
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      SUBROUTINE slPLTE (DATE, ELONG, PHI, JFORM, EPOCH,
     :                       ORBINC, ANODE, PERIH, AORQ, E,
     :                       AORL, DM, RA, DEC, R, JSTAT)

     - - - - - - -
      P L T E
     - - - - - - -

  Topocentric apparent RA,Dec of a Solar-System object whose
  heliocentric orbital elements are known.

  Given:
     DATE      d     MJD of observation (JD - 2400000.5)
     ELONG     d     observer's east longitude (radians)
     PHI       d     observer's geodetic latitude (radians)
     JFORM     i     choice of element set (1-3; Note 4)
     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:
     RA,DEC    d     RA, Dec (topocentric apparent, radians)
     R         d     distance from observer (AU)
     JSTAT     i     status:  0 = OK
                             -1 = illegal JFORM
                             -2 = illegal E
                             -3 = illegal AORQ
                             -4 = illegal DM
                             -5 = numerical error

  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 longitude and latitude allow correction for geocentric
     parallax.  This is usually a small effect, but can become
     important for Earth-crossing asteroids.  Geocentric positions
     can be generated by appropriate use of routines slEVP and
     slPLNE.

  3  The elements are with respect to the J2000 ecliptic and equinox.

  4  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
     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
     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

  5  Unused elements (DM for JFORM=2, AORL and DM for JFORM=3) are
     not accessed.

  Called: slGMST, slDT, slEPJ, slPVOB, slPRNU,
          slPLNE, slDMXV, slDC2S, slDA2P

  P.T.Wallace   Starlink   17 March 1999

  Copyright (C) 1999 Rutherford Appleton Laboratory
  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.

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