Polar alignment of the
scope (I stress,
not the mount) is achieved by centering the SCP on the centre of the video monitor screen connected to the camera, by adjusting the mount alt and az screws. I locate the SCP in the star field shown in for example the more detailed FOV2 diagram at
http://www.users.on.net/~pbl/art_sh_polar_alignment.htm.
The field looks much the same as shown in the diagram, although my field is somewhat smaller and of course rectangular.
For example, using the two stars either side of the SCP it is not hard to do that to within 3 or 4 arcmin (the radius of the circle in the diagram is about 22 arcmin).