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authorJoe Hunkeler <jhunkeler@gmail.com>2015-08-11 16:51:37 -0400
committerJoe Hunkeler <jhunkeler@gmail.com>2015-08-11 16:51:37 -0400
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+.help mapqk Jun99 "Slalib Package"
+.nf
+
+ SUBROUTINE slMAPQ (RM, DM, PR, PD, PX, RV, AMPRMS, RA, DA)
+
+ - - - - - -
+ M A P Q
+ - - - - - -
+
+ 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.
+
+.fi
+.endhelp