bk>  The North Pole moves against the sky in a 23000 year cycle. I 
 bk> don't think I've noticed the change. There may be small wobbles, 
 bk> but I doubt they have much effect.

not only that but the magnetic poles also wander around... i don't know
what their cycle is but it is easily trackable...

here's some interesting info according to a pdf available at
spacemath.gsfc.nasa.gov...

1. since the 1700 mapmakers have known that the bearings to seaports and
other fixed landmarks change in a steady manner from decade to decade.

2. from 300AD to 2000AD, the north magnetic pole has wandered some 18000+km.

3. the shortest distance the NMP wandered in a 100 year period is an
average of 507km.

4. the longest distance the NMP wandered in a 100 year period is an average
of 2470km.

5. the average speed of the NMP wander, between 300AD and 2000AD is 11km per year.

6. the average fastest speed of the NMP wander is 24.5km per year and that
was between 1300AD and 1400AD.

;)

)\/(ark