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 geodetic latitude of observing station (radians)

$$[\,\alpha,\delta\,]$$ RA,DA R

ST R local apparent sidereal time (radians)

RETURNED:

sla_RVEROT 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.