SLA_RVEROT - RV Corrn to Earth Centre
ACTION:
Velocity component in a given direction due to Earth rotation.
CALL:
R = sla_RVEROT (PHI, RA, DA, ST)
GIVEN:
PHI R geodetic latitude of observing station (radians)
RA,DA R apparent alpha, delta (radians)
ST R local apparent sidereal time (radians)
RETURNED:
sla_RVEROT R Component of Earth rotation in direction RA,DA (km s-1)
NOTES:
1. Sign convention: the result is positive when the observatory is
receding from the given point on the sky.
2. Accuracy: the simple algorithm used assumes a spherical Earth and
an observing station at sea level; for actual observing sites, the
error is unlikely to be greater than 0.0005 km s-1. For
applications requiring greater precision, use the routine
sla_PVOBS.