The History of Celestial Navigation

The US Naval Observatory still publishes a book like this, but it's mostly an electronic form. The smart guys back at the observatory would devise some big complicated mathematical formulas for the locations of the stars this year and then send it to the computers. Every calculation was done twice by two different guys. And they wouldn't have known why that was happening as well. They started reintroducing celestial navigation in case the, the ship systems get hacked.