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SLA_FK5HZ - FK5 to Hipparcos, no P.M.   

ACTION:
Transform an FK5 (J2000) star position into the frame of the Hipparcos catalogue, assuming zero Hipparcos proper motion.

CALL:
CALL sla_FK52H (R5,D5,EPOCH,RH,DH)

GIVEN:

R5 D J2000.0 FK5 $\alpha$ (radians)
D5 D J2000.0 FK5 $\delta$ (radians)
EPOCH D Julian epoch (TDB)

RETURNED:

RH D Hipparcos $\alpha$ (radians)
DH D Hipparcos $\delta$ (radians)

NOTES:
1.
The $\alpha$ proper motions are $\dot{\alpha}$ rather than $\dot{\alpha}\cos\delta$, 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_FK52H, sla_H2FK5, sla_HFK5Z.

REFERENCE:
Feissel, M. & Mignard, F., 1998., Astron.Astrophys. 331, L33-L36.


next up previous
Next: SLA_FLOTIN - Decode a Real Number
Up: SUBPROGRAM SPECIFICATIONS
Previous: SLA_FK54Z - FK5 to FK4, no P.M. or Parallax

SLALIB --- Positional Astronomy Library
Starlink User Note 67
P. T. Wallace
12 October 1999
E-mail:ptw@star.rl.ac.uk