1 files changed, 67 insertions, 0 deletions
diff --git a/src/slalib/addet.f b/src/slalib/addet.f
new file mode 100644
index 0000000..c039aff
--- /dev/null
+++ b/src/slalib/addet.f
@@ -0,0 +1,67 @@
+      SUBROUTINE sla_ADDET (RM, DM, EQ, RC, DC)
+*+
+*     - - - - - -
+*      A D D E T
+*     - - - - - -
+*
+*  Add the E-terms (elliptic component of annual aberration)
+*  to a pre IAU 1976 mean place to conform to the old
+*  catalogue convention (double precision)
+*
+*  Given:
+*     RM,DM     dp     RA,Dec (radians) without E-terms
+*     EQ        dp     Besselian epoch of mean equator and equinox
+*
+*  Returned:
+*     RC,DC     dp     RA,Dec (radians) with E-terms included
+*
+*  Note:
+*
+*     Most star positions from pre-1984 optical catalogues (or
+*     derived from astrometry using such stars) embody the
+*     E-terms.  If it is necessary to convert a formal mean
+*     place (for example a pulsar timing position) to one
+*     consistent with such a star catalogue, then the RA,Dec
+*     should be adjusted using this routine.
+*
+*  Reference:
+*     Explanatory Supplement to the Astronomical Ephemeris,
+*     section 2D, page 48.
+*
+*  Called:  sla_ETRMS, sla_DCS2C, sla_DCC2S, sla_DRANRM, sla_DRANGE
+*
+*  P.T.Wallace   Starlink   18 March 1999
+*
+*  Copyright (C) 1999 Rutherford Appleton Laboratory
+*-
+
+      IMPLICIT NONE
+
+      DOUBLE PRECISION RM,DM,EQ,RC,DC
+
+      DOUBLE PRECISION sla_DRANRM
+
+      DOUBLE PRECISION A(3),V(3)
+
+      INTEGER I
+
+
+
+*  E-terms vector
+      CALL sla_ETRMS(EQ,A)
+
+*  Spherical to Cartesian
+      CALL sla_DCS2C(RM,DM,V)
+
+*  Include the E-terms
+      DO I=1,3
+         V(I)=V(I)+A(I)
+      END DO
+
+*  Cartesian to spherical
+      CALL sla_DCC2S(V,RC,DC)
+
+*  Bring RA into conventional range
+      RC=sla_DRANRM(RC)
+
+      END