The following e-mail message from the author of "The Sky". This software package has extensive features for visualising astronomical phenomenon. including proper motion. However, it does not currently do 3-d plotting of data. and hence is not capable of displaying parallax effects or radial motion. Essentially, stars are fixed on the celestial sphere at infinity.

From: "Thomas M. Bisque" 
To: Brian von Konsky 
Subject: RE: proper motion and parallax in The Sky
Date: Mon, 14 Jun 1999 16:17:04 -0600
X-Priority: 3
MIME-Version: 1.0

With the data from the Hipparcos and Tycho stars we can plot the effect
of proper motion over time.  If you skip say 10000 days you can see the
stars change their positions.  You can also plot a velocity vector for a
given amount of time in years and see what direction the stars is
heading.  Note that we do not do any 3-d plotting with this data.  We
have plans to incorporate this type of plotting in the future.