Sextant

Definition

A sextant is a navigational instrument used to measure the angle between two visible objects, typically the horizon and a celestial body, to determine one's latitude and longitude at sea. This tool revolutionized navigation by allowing sailors to accurately calculate their position, significantly enhancing their ability to traverse the open ocean, and directly contributing to advances in celestial navigation, addressing navigational challenges, and improving cartography.

5 Must Know Facts For Your Next Test

1. The sextant was developed in the 18th century, building on earlier devices like the astrolabe and quadrant, and it became a standard instrument for navigation at sea.
2. Sailors used the sextant by measuring the angle between a celestial body, such as the sun or stars, and the horizon during a specific time of day to calculate their geographic position.
3. The sextant's design includes a movable arm called an index arm that pivots around a central pivot point, allowing for precise angle measurements.
4. Using a sextant requires knowledge of celestial navigation principles, including an understanding of how to read nautical almanacs and apply corrections for factors like atmospheric refraction.
5. Accurate use of a sextant contributed significantly to better cartography, as it enabled sailors to gather precise data on their positions, which could then be used to create more reliable maps.

Review Questions

• How did the invention of the sextant improve celestial navigation for sailors during the Age of Exploration?
  • The invention of the sextant greatly improved celestial navigation by providing sailors with a more accurate method to measure angles between celestial bodies and the horizon. This precision allowed them to determine their latitude and longitude more effectively than previous tools. As a result, navigators could make more informed decisions about their routes across vast oceans, reducing the risk of getting lost at sea.
• What navigational challenges did mariners face before the widespread use of the sextant, and how did it offer solutions?
  • Before the sextant, mariners faced significant challenges in determining their positions accurately while at sea. Instruments like the astrolabe were less precise, making it difficult to obtain reliable measurements in varying weather conditions. The sextant addressed these challenges by offering enhanced accuracy and ease of use, allowing sailors to make quick adjustments and calculations. This led to safer voyages and more reliable exploration of uncharted waters.
• Evaluate the impact of the sextant on mapmaking practices during the Age of Exploration and its broader implications for global trade.
  • The impact of the sextant on mapmaking practices was profound during the Age of Exploration, as it enabled explorers to gather precise positional data that directly influenced cartography. This accuracy allowed for the creation of more detailed and reliable maps, facilitating trade routes and maritime navigation. As a result, global trade expanded significantly because ships could navigate confidently through previously perilous waters. The enhanced understanding of geography also encouraged further exploration and colonization efforts worldwide.

Related terms

Astrolabe: An ancient instrument used for solving problems related to time and the position of the stars and planets.

Chronometer:

A precise timekeeping device essential for determining longitude by comparing local time with a known reference time.

Latitude: The geographic coordinate that specifies the north-south position of a point on the Earth's surface.