.help hfk5z Jun99 "Slalib Package" .nf 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. .fi .endhelp