From 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 Mon Sep 17 00:00:00 2001
From: Joe Hunkeler <jhunkeler@gmail.com>
Date: Tue, 11 Aug 2015 16:51:37 -0400
Subject: Repatch (from linux) of OSX IRAF

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+.help fk45z Jun99 "Slalib Package"
+.nf
+
+      SUBROUTINE slF45Z (R1950,D1950,BEPOCH,R2000,D2000)
+
+     - - - - - -
+      F 4 5 Z
+     - - - - - -
+
+  Convert B1950.0 FK4 star data to J2000.0 FK5 assuming zero
+  proper motion in the FK5 frame (double precision)
+
+  This routine converts stars from the old, Bessel-Newcomb, FK4
+  system to the new, IAU 1976, FK5, Fricke system, in such a
+  way that the FK5 proper motion is zero.  Because such a star
+  has, in general, a non-zero proper motion in the FK4 system,
+  the routine requires the epoch at which the position in the
+  FK4 system was determined.
+
+  The method is from Appendix 2 of Ref 1, but using the constants
+  of Ref 4.
+
+  Given:
+     R1950,D1950     dp    B1950.0 FK4 RA,Dec at epoch (rad)
+     BEPOCH          dp    Besselian epoch (e.g. 1979.3D0)
+
+  Returned:
+     R2000,D2000     dp    J2000.0 FK5 RA,Dec (rad)
+
+  Notes:
+
+  1)  The epoch BEPOCH is strictly speaking Besselian, but
+      if a Julian epoch is supplied the result will be
+      affected only to a negligible extent.
+
+  2)  Conversion from Besselian epoch 1950.0 to Julian epoch
+      2000.0 only is provided for.  Conversions involving other
+      epochs will require use of the appropriate precession,
+      proper motion, and E-terms routines before and/or
+      after FK45Z is called.
+
+  3)  In the FK4 catalogue the proper motions of stars within
+      10 degrees of the poles do not embody the differential
+      E-term effect and should, strictly speaking, be handled
+      in a different manner from stars outside these regions.
+      However, given the general lack of homogeneity of the star
+      data available for routine astrometry, the difficulties of
+      handling positions that may have been determined from
+      astrometric fields spanning the polar and non-polar regions,
+      the likelihood that the differential E-terms effect was not
+      taken into account when allowing for proper motion in past
+      astrometry, and the undesirability of a discontinuity in
+      the algorithm, the decision has been made in this routine to
+      include the effect of differential E-terms on the proper
+      motions for all stars, whether polar or not.  At epoch 2000,
+      and measuring on the sky rather than in terms of dRA, the
+      errors resulting from this simplification are less than
+      1 milliarcsecond in position and 1 milliarcsecond per
+      century in proper motion.
+
+  References:
+
+     1  Aoki,S., et al, 1983.  Astron.Astrophys., 128, 263.
+
+     2  Smith, C.A. et al, 1989.  "The transformation of astrometric
+        catalog systems to the equinox J2000.0".  Astron.J. 97, 265.
+
+     3  Yallop, B.D. et al, 1989.  "Transformation of mean star places
+        from FK4 B1950.0 to FK5 J2000.0 using matrices in 6-space".
+        Astron.J. 97, 274.
+
+     4  Seidelmann, P.K. (ed), 1992.  "Explanatory Supplement to
+        the Astronomical Almanac", ISBN 0-935702-68-7.
+
+  Called:  slDS2C, slEPJ, slEB2D, slDC2S, slDA2P
+
+  P.T.Wallace   Starlink   21 September 1998
+
+  Copyright (C) 1998 Rutherford Appleton Laboratory
+  Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
+
+.fi
+.endhelp
-- 
cgit 

