SLA_FK52H

FK5 to Hipparcos

ACTION:
Transform an FK5 (J2000) position and proper motion into the frame of the Hipparcos catalogue.
CALL:
CALL sla_FK52H (R5, D5, DR5, DD5, RH, DH, DRH, DDH)
GIVEN:

R5

D

J2000.0 FK5 α (radians)

D5

D

J2000.0 FK5 δ (radians)

DR5

D

J2000.0 FK5 proper motion in α (radians per Julian year)

DD5

D

J2000.0 FK5 proper motion in δ (radians per Julian year)


RETURNED:

RH

D

Hipparcos α (radians)

DH

D

Hipparcos δ (radians)

DRH

D

Hipparcos proper motion in α (radians per Julian year)

DDH

D

Hipparcos proper motion in δ (radians per Julian year)


NOTES:
(1)
The α proper motions are α̇ rather than α̇ cos δ, and are per year rather than per century.
(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 adopted epoch J2000.0 FK5 to Hipparcos orientation and spin values are as follows (see reference):

            

orientation
   spin   
x − 19.9       − 0.30  
y − 9.1       + 0.60  
z + 22.9       + 0.70  
mas       mas/y 

These 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)
See also sla_FK5HZ, sla_H2FK5, sla_HFK5Z.
REFERENCE:
Feissel, M. & Mignard, F., 1998., Astron.Astrophys. 331, L33-L36.