Anyone who wants to navigate astronomically will still have to use a sextant today. But that can also be seen as a sporting challenge. Everything else, however, such as mountains of astronomical documents, calculators, drawing utensils and the ability to use all these things, is history.

They have been replaced by modern apps that allow anyone with a mobile phone or tablet to calculate their location. Knowledge of mathematics or astronomy is no longer necessary, and the location is displayed on an zoomable electronic map on the screen.

This makes the decision to carry an astronomical navigation backup on board, in the interests of good seamanship, much easier.