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SLA_PM - Proper Motion   

ACTION:
Apply corrections for proper motion to a star $[\,\alpha,\delta\,]$.
CALL:
CALL sla_PM (R0, D0, PR, PD, PX, RV, EP0, EP1, R1, D1)

GIVEN:

R0,D0 D $[\,\alpha,\delta\,]$ at epoch EP0 (radians)
PR,PD D proper motions: rate of change of $[\,\alpha,\delta\,]$ (radians per year)
PX D parallax (arcsec)
RV D radial velocity (km s-1, +ve if receding)
EP0 D start epoch in years (e.g. Julian epoch)
EP1 D end epoch in years (same system as EP0)

RETURNED:

R1,D1 D $[\,\alpha,\delta\,]$ at epoch EP1 (radians)

NOTE:
The $\alpha$ proper motions are $\dot{\alpha}$ rather than $\dot{\alpha}\cos\delta$, and are in the same coordinate system as R0,D0.

REFERENCES:
1.
1984 Astronomical Almanac, pp B39-B41.
2.
Lederle & Schwan, 1984. Astr. Astrophys. 134, 1-6.


next up previous
Next: SLA_POLMO - Polar Motion
Up: SUBPROGRAM SPECIFICATIONS
Previous: SLA_PLANTE - of Planet from Elements

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