I learned this in college 48 years go, problem is I have forgotten more than I ever knew. I know the answer is not very hard like 20 degrees but the internet is pissing me off. I looked this up and I get FAKE stuff like advertisements. Novels with many pages to read that never tell the answer. Formulas to calculate the answer for lots of things but what I want to know. I give up I am tired of looking. I know magnet north moves around but there is a average place where it usually is? I am trying to position solar panels so they get the same amount of sun in the morning as they do in the evening. I have a 1/4" dowel rod stuck straight up in the yard the sun shadow lines up the compus needle at 1:10 PM. This is magnetic north not true north. Setting solar panels at true north can not be that hard.