SLA_ADDET - Add E-terms of Aberration

ACTION:

Add the E-terms (elliptic component of annual aberration) to a pre IAU 1976 mean place to conform to the old catalogue convention.

CALL:

CALL sla_ADDET (RM, DM, EQ, RC, DC)

GIVEN:

RM,DM	D	$[ \alpha,\delta ]$ without E-terms (radians)
EQ	D	Besselian epoch of mean equator and equinox

RETURNED:

RC,DC

D

$[ \alpha,\delta ]$ with E-terms included (radians)

NOTE:

Most star positions from pre-1984 optical catalogues (or obtained by astrometry with respect to such stars) have the E-terms built-in. 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 $[ \alpha,\delta ]$ should be adjusted using this routine.

REFERENCE:

Explanatory Supplement to the Astronomical Ephemeris, section 2D, page 48.