The improvements in weapons, ships, clothing, rocketry and underwater techniques helped with the improvement of navigation.
Some of the world’s most important explorers used astrolabes on the expeditions to faraway lands. The astrolabe was used by Christopher Columbus in his voyage to the Americas. Ferdinand Magellan and his crew relied also on an astrolabe during the first circumnavigation of Earth. Many Arab travellers used it too to navigate the desert.
In the 16th century, before the invention of the telescope, Tycho Brahe (Danish astronomer) constructed an astrolabe with a radius of 10 ft. Until superseded by the sextant during the 18th century, smaller types of astrolabes were the principal instruments used by navigators.
Sailors used the stars for guidance. For measuring the altitude of celestial bodies to determine ship position, they used some instruments like octants and sextants. The octant was used to work out the latitude but not longitude. In 1757 it was succeeded by the sextant, which could measure both.
