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SUBROUTINE sla_SUBET (RC, DC, EQ, RM, DM)
*+
* - - - - - -
* S U B E T
* - - - - - -
*
* Remove the E-terms (elliptic component of annual aberration)
* from a pre IAU 1976 catalogue RA,Dec to give a mean place
* (double precision)
*
* Given:
* RC,DC dp RA,Dec (radians) with E-terms included
* EQ dp Besselian epoch of mean equator and equinox
*
* Returned:
* RM,DM dp RA,Dec (radians) without E-terms
*
* Called:
* sla_ETRMS, sla_DCS2C, sla_,DVDV, sla_DCC2S, sla_DRANRM
*
* Explanation:
* Most star positions from pre-1984 optical catalogues (or
* derived from astrometry using such stars) embody the
* E-terms. This routine converts such a position to a
* formal mean place (allowing, for example, comparison with a
* pulsar timing position).
*
* Reference:
* Explanatory Supplement to the Astronomical Ephemeris,
* section 2D, page 48.
*
* P.T.Wallace Starlink 10 May 1990
*
* Copyright (C) 1995 Rutherford Appleton Laboratory
*
* License:
* 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 (see SLA_CONDITIONS); if not, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
*
*-
IMPLICIT NONE
DOUBLE PRECISION RC,DC,EQ,RM,DM
DOUBLE PRECISION sla_DRANRM,sla_DVDV
DOUBLE PRECISION A(3),V(3),F
INTEGER I
* E-terms
CALL sla_ETRMS(EQ,A)
* Spherical to Cartesian
CALL sla_DCS2C(RC,DC,V)
* Include the E-terms
F=1D0+sla_DVDV(V,A)
DO I=1,3
V(I)=F*V(I)-A(I)
END DO
* Cartesian to spherical
CALL sla_DCC2S(V,RM,DM)
* Bring RA into conventional range
RM=sla_DRANRM(RM)
END
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