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.help hfk5z Jun99 "Slalib Package"
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SUBROUTINE slHF5Z (RH,DH,EPOCH,R5,D5,DR5,DD5)
- - - - - -
H F 5 Z
- - - - - -
Transform a Hipparcos star position into FK5 J2000, assuming
zero Hipparcos proper motion.
(double precision)
Given:
RH d Hipparcos RA (radians)
DH d Hipparcos Dec (radians)
EPOCH d Julian epoch (TDB)
Returned (all FK5, equinox J2000, epoch EPOCH):
R5 d RA (radians)
D5 d Dec (radians)
Called: slDS2C, slDAVM, slDMXV, slDAVM, slDMXM,
slDIMV, slDVXV, slDC6S
Notes:
1) The proper motion in RA is dRA/dt rather than cos(Dec)*dRA/dt.
2) The FK5 to Hipparcos transformation consists of a pure
rotation and spin; zonal errors in the FK5 catalogue are
not taken into account.
3) The published orientation and spin components are interpreted
as "axial vectors". An axial vector points at the pole of the
rotation and its length is the amount of rotation in radians.
4) It was the intention that Hipparcos should be a close
approximation to an inertial frame, so that distant objects
have zero proper motion; such objects have (in general)
non-zero proper motion in FK5, and this routine returns those
fictitious proper motions.
5) The position returned by this routine is in the FK5 J2000
reference frame but at Julian epoch EPOCH.
6) See also slFK5H, slHFK5, slF5HZ.
Reference:
M.Feissel & F.Mignard, Astron. Astrophys. 331, L33-L36 (1998).
P.T.Wallace Starlink 7 October 1998
Copyright (C) 1998 Rutherford Appleton Laboratory
Copyright (C) 1995 Association of Universities for Research in Astronomy Inc.
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