Regardless of the developments in electronic navigation this remains an essential requirement for anyone learning and practising astro-navigation.

The Practical Guide to Celestial Navigation: Step-by-step instructions for when you've lost the plot

Pilots and Pilotage in Britain and Northern Europe

Master the sextant in simple steps by Tom Cunliffe.

This 2018 edition has been brought fully up to date.

The sextant is the treasured navigational device of generations of seamen and airmen. It enables position to be determined with good accuracy for ocean navigation, and it was the combination of sextant and chronometer that allowed safe navigation of the oceans for generations of seafarers.