What inventions greatly contributed to the expansion of sea exploration in the 1400s?

In the 1400s, several key inventions significantly advanced sea exploration, notably the compass and the astrolabe. The compass allowed navigators to determine direction accurately, enhancing their ability to travel across open water. The astrolabe enabled sailors to measure the altitude of celestial bodies, aiding in determining latitude. Together, these tools facilitated longer voyages and the discovery of new trade routes, ultimately leading to the Age of Exploration.