Fair point. > That 19th century captain measured the angle between the pole star and the local horizon with a sextant; Which immediately provided latitude. To

Fair point. > That 19th century captain measured the angle between the pole star and the local horizon with a sextant; Which immediately provided latitude. To get longitude, he did the same with just about any other star and correlated the angle to an accurate clock and carefully-prepared tables. That "accurate clock" business was why longitude was such a difficult navigational problem for so long until John Harrison finally cracked it. (I know this is getting OT but I find it fascinating.) https://en.m.wikipedia.org/wiki/John_Harrison https://en.m.wikipedia.org/wiki/John_Harrison