GPS Geo-caching

[Paul]

I am used to geo-caching with a map and compass but have found that either I'm getting older and dafter or North is "dancing" round a bit.

I recently got an E-Trex GPS but setting the North on the GPS as Magnetic North, there is something like a 5 degree difference between the GPS and my trusty old Silva.

I read somewhere that the poles are shifting rapidly but I thought that the GPS system took that into account so anyone got an idea about what's going on?

I ask because I may need to find my Geo-cache at night it might be nice to use the GPS and walk to a waypoint.

Problem is I'm thinking that any waypoint set on the GPS will gradually "drift" if magnetic north keeps up it's little dance and GPS's can't cope.

Thanks.