How did sailors use an astrolabe to find their latitude?

Sailors used the astrolabe to determine their latitude by measuring the elevation angle of celestial bodies, such as the polestar or the noonday Sun.12

By observing the angle between the celestial object and the vertical, navigators could calculate their north-south position. While the astrolabe was a sophisticated tool adapted from astronomy, it functioned by using a sighting rule known as an alidade to align the instrument with the target in the sky. Once the elevation was measured, the reading was converted into a latitude coordinate, often with the aid of an almanac, especially when stars were not visible or when the navigator was near the Equator.13

Although the astrolabe was a significant advancement in celestial navigation, it was eventually supplanted by more specialized instruments like the cross-staff and, later, the sextant, which offered greater ease of use and precision for maritime travel.13