.help mapqk Jun99 "Slalib Package"
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      SUBROUTINE slMAPQ (RM, DM, PR, PD, PX, RV, AMPRMS, RA, DA)

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      M A P Q
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  Quick mean to apparent place:  transform a star RA,Dec from
  mean place to geocentric apparent place, given the
  star-independent parameters.

  Use of this routine is appropriate when efficiency is important
  and where many star positions, all referred to the same equator
  and equinox, are to be transformed for one epoch.  The
  star-independent parameters can be obtained by calling the
  slMAPA routine.

  If the parallax and proper motions are zero the slMAPZ
  routine can be used instead.

  The reference frames and timescales used are post IAU 1976.

  Given:
     RM,DM    d      mean RA,Dec (rad)
     PR,PD    d      proper motions:  RA,Dec changes per Julian year
     PX       d      parallax (arcsec)
     RV       d      radial velocity (km/sec, +ve if receding)

     AMPRMS   d(21)  star-independent mean-to-apparent parameters:

       (1)      time interval for proper motion (Julian years)
       (2-4)    barycentric position of the Earth (AU)
       (5-7)    heliocentric direction of the Earth (unit vector)
       (8)      (grav rad Sun)*2/(Sun-Earth distance)
       (9-11)   barycentric Earth velocity in units of c
       (12)     sqrt(1-v**2) where v=modulus(ABV)
       (13-21)  precession/nutation (3,3) matrix

  Returned:
     RA,DA    d      apparent RA,Dec (rad)

  References:
     1984 Astronomical Almanac, pp B39-B41.
     (also Lederle & Schwan, Astron. Astrophys. 134,
      1-6, 1984)

  Notes:

  1)  The vectors AMPRMS(2-4) and AMPRMS(5-7) are referred to
      the mean equinox and equator of epoch EQ.

  2)  Strictly speaking, the routine is not valid for solar-system
      sources, though the error will usually be extremely small.
      However, to prevent gross errors in the case where the
      position of the Sun is specified, the gravitational
      deflection term is restrained within about 920 arcsec of the
      centre of the Sun's disc.  The term has a maximum value of
      about 1.85 arcsec at this radius, and decreases to zero as
      the centre of the disc is approached.

  Called:
     slDS2C       spherical to Cartesian
     slDVDV        dot product
     slDMXV        matrix x vector
     slDC2S       Cartesian to spherical
     slDA2P      normalize angle 0-2Pi

  P.T.Wallace   Starlink   23 August 1996

  Copyright (C) 1996 Rutherford Appleton Laboratory
  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.

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