Before revision: Easy way to calculate compass magnetic or true north is maintaining the original signs (+ for east and -for west): C+(Var)= M+(Dev)= T T-(Dev)= M-(Var)= C Sea School (1977) True Virgins Make Dull Companions.
After revision: for variation and deviation/Easy way to calculate compass magnetic or true north is maintaining the original signs (+ for east and -for west): C+(Var)= M+(Dev)= T T-(Dev)= M-(Var)= C Sea School (1977) True Virgins Make Dull Companions.