> I was reading about survey grade compasses, and they are balanced to account for magnetic dip, the closer you get to the poles the more dip you have. Wet, or

> I was reading about survey grade compasses, and they are balanced to account for magnetic dip, the closer you get to the poles the more dip you have. Wet, or whiskey compasses used in aircraft are counterweighted to account for this. There are mnemonics for pilots to know how to handle the error induced by this counterweight: "OSUN—overshoot south, undershoot north" and "ANDS—accelerate north, decelerate south". https://www.aopa.org/news-and-media/all-news/2012/may/flight-training-magazine/technique--compass-error https://www.aopa.org/news-and-media/all-news/2012/may/flight...