Polar Alignment Wedge.
Doug: angle of wedge cut and fashoined to 53deg 43minutes (well as near as I measure when extrapolating out to 30cm and doing the trig). An aluminium flat was added to improve performance across the surface. The device fits into the standard dovetail receptor on the mount head. Takes the latitude setting dimension and error out of locating polaris for polar aligment. It is pretty well spot on.