SHOW PV [[CLEAN|DIRTY|SKY] Axis Offset]
Extract from the indicated data cube a Position-Velocity image at the
specified Offset (in arcsec) along the specified Axis (X or Y), and dis-
play it.
The data cube name is optional: the last specified one is used by de-
fault.
will simply redisplay (with different controls, see SHOW PV ? to
have a list) the last extracted Position-Velocity image.