page_title: Iberian nautical sciences, 1400–1600
section_title: Martin Cortes and the astrolabe
hierarchical_section_title: Iberian nautical sciences, 1400–1600 / Martin Cortes and the astrolabe
caption_attribution_description: English: Planispheric astrolabe, gilt brass, 1553. Français&#160;: Astrolabe planisphérique, laiton doré, 1553.
context_page_description: Throughout the early age of exploration, it became increasingly clear that the residents of the Iberian Peninsula were experts at navigation, sailing, and expansion. From Henry the Navigator's first adventures down the African coast to Columbus's fabled expedition resulting in the discovery of the new world, the figures that catalyzed the European appetite for expansion and imperialism heralded from either Spain or Portugal. However, merely a century earlier, nautical travel for most peoples was resigned to keeping within sight of a coastline and very rarely did ships venture out into deeper waters. The period's ships were not able to handle the forces of open ocean travel and the crewmen had neither the ability nor the necessary materials to keep themselves from getting lost. A sailor's ability to travel was dictated by the technology available, and it wasn’t until the late 15th century that the development of the nautical sciences on the Iberian Peninsula allowed for the genesis of long distance shipping by directly effecting, and leading to the creation of, new tools and techniques relative to navigation.
context_section_description: Oftentimes the lives of sailors and their captain were completely dependent upon precise plotting of current location and anticipated destination, as a result a number of techniques and instruments were employed in order to ensure the accuracy of a reading. Designed to work in concert with a quadrant, which came to replace the kamal entirely in the 14th century, the mariner's astrolabe also measured the altitude of celestial bodies; however this tool could use the sun as a reference point as well thus allowing for the continual plotting of a ship's course in day or night. It also had the ability to determine latitude in rough seas, an essential ability for long distance mariners due to the unpredictability of the sea; the quadrant and kamal both required calm waters.
  Mentioned as early as the close of the  13th century, a conclusive guide on its construction and use was not available until 1551 when Spanish cosmographer Martin Cortes de Albacar published what would become one of the first manuals on seafaring navigation. Cortes himself was born in Aragon in 1510. Maturing during the fervor of the age of exploration, he devoted his life to the nautical sciences and developed the mariner's astrolabe along with investigating and proposing magnetic deviation and the existence of magnetic poles. He spent the second half of his life from 1530 until his death in Cadiz as an instructor to ship pilots on the topics of both cosmography and navigation. Translated into English as the Arte of Navigation, his book became the backbone of sailing instruction for many of the world's naval powers until the 19th century.
caption: Astrolabe Jean Naze MBA Lyon 1966-1
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