Which specific navigational instrument, often a simplified version of the planispheric astrolabe, was crucial for determining latitude during ocean voyages?

Mariner's astrolabe

For maritime history, the Mariner's astrolabe holds a distinct importance. Sailors required a portable, durable tool that could accurately measure latitude at sea. While the more ornate planispheric astrolabes were complex and suitable for land-based use, mariners employed specialized, often simplified versions known as Mariner's astrolabes. These instruments were specifically used to measure the altitude of the North Star at night or the altitude of the Sun precisely at noon. This accurate latitude determination was a massive leap forward for navigation and trade in eras preceding the development of the reliable marine chronometer, which would later enable longitude calculation.