; ROTMEAS
;---------------------------------------------------------------
;! Tells the rotation measure of a source
;# ADVERB CALIBRATION POLARIZATION
;-----------------------------------------------------------------------
;;  Copyright (C) 2019
;;  Associated Universities, Inc. Washington DC, USA.
;;
;;  This program is free software; you can redistribute it and/or
;;  modify it under the terms of the GNU General Public License as
;;  published by the Free Software Foundation; either version 2 of
;;  the License, or (at your option) any later version.
;;
;;  This program is distributed in the hope that it will be useful,
;;  but WITHOUT ANY WARRANTY; without even the implied warranty of
;;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;  GNU General Public License for more details.
;;
;;  You should have received a copy of the GNU General Public
;;  License along with this program; if not, write to the Free
;;  Software Foundation, Inc., 675 Massachusetts Ave, Cambridge,
;;  MA 02139, USA.
;;
;;  Correspondence concerning AIPS should be addressed as follows:
;;         Internet email: aipsmail@nrao.edu.
;;         Postal address: AIPS Project Office
;;                         National Radio Astronomy Observatory
;;                         520 Edgemont Road
;;                         Charlottesville, VA 22903-2475 USA
;-----------------------------------------------------------------------
;---------------------------------------------------------------
ROTMEAS   LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC
----------------------------------------------------------------
ROTMEAS
Type: Adverb  (real)
Use:  Used to tell a task a rotation measure in radians per meter
      squared.

Null value:  0 -> no rotation measure

Tasks:
   SPLIT....Converts multi-source to single-source UV files with
            calibration.  It ROTMEAS is not zero, the output is forced
            to IQUV or RR/LL/RL/LR Stokes and Q and U are corrected by
            the rotation measure into the values they would have at 0
            wavelength.
                Qout = Uin sin(2D) + Qin cos(2D)
                Uout = Uin cos(2D) - Qin sin(2D)
                RLout = RLin (cos(2D) - j sin(2D))
                LRout = LRin (cos(2D) + j sin(2D))
            where j = sqrt(-1) and D = ROTMEAS * Lambda^2.
----------------------------------------------------------------
