palRverot palRverot - Velocity component in a given direction due to Earth rotation

Description:

Calculate the velocity component in a given direction due to Earth rotation.

The simple algorithm used assumes a spherical Earth, of a radius chosen to give results accurate to about 0.0005 km/s for observing stations at typical latitudes and heights. For applications requiring greater precision, use the routine palPvobs.

Invocation:

double palRverot ( double phi, double ra, double da, double st );

Arguments:

phi = double (Given)

latitude of observing station (geodetic) (radians)

ra = double (Given)

apparent RA (radians)

da = double (Given)

apparent Dec (radians)

st = double (Given)

Returned Value:

palRverot = double

Component of Earth rotation in direction RA,DA (km/s). The result is $+$ve when the observatory is receding from the given point on the sky.