A compass tells you magnetic north, not true north. You'll have to add or subtract depending on your location from magnetic north (which wanders from year to year).
Here's a site to generate the needed dimensions and positions automatically so you can verify that you've got yours right:
A compass tells you magnetic north, not true north. You'll have to add or subtract depending on your location from magnetic north (which wanders from year to year).
Here's a site to generate the needed dimensions and positions automatically so you can verify that you've got yours right:
http://analemmatic.sourceforge.net/cgi-bin/sundial.pl
It makes a PDF of plans specific for your latitude and longitude.