# Sextant vs. Quadrant: What's the Difference?

Edited by Harlon Moss || By Janet White || Updated on September 28, 2023

**A sextant is a navigational instrument measuring angular distances, while a quadrant is both a quarter of a circle and an instrument measuring altitudes in navigation or astronomy.**

## Key Differences

A sextant and a quadrant, while both instrumental in navigation and astronomy, have distinct differences. A sextant is a sophisticated navigational tool that mariners use to measure the angular distance between two visible objects. It has a scope through which the user observes, and its arc is one-sixth of a circle or 60 degrees, giving it the name "sextant." Conversely, a quadrant is an instrument that also serves navigational and astronomical purposes, and its principal use is to measure the altitude of a celestial object above the horizon. A quadrant, as the name implies, has an arc that is a quarter of a circle, or 90 degrees.

In terms of construction and functionality, the sextant has a small, movable telescope attached to the frame, allowing for increased precision in measurements. The sextant is mainly used for celestial navigation, helping sailors and aviators determine their latitude by measuring the angle between a celestial body and the horizon. In contrast, the quadrant, a simpler device, typically consists of a quarter-circle plate and a plumb line to determine vertical. The quadrant is one of the oldest astronomical instruments, dating back to ancient times, used by astronomers to measure angles and by navigators to determine their position at sea.

The sextant and the quadrant both have their historical significance in navigation and astronomy. The sextant, with its enhanced precision, has been instrumental in enabling long ocean voyages and exploring uncharted territories. The quadrant, being an ancient instrument, has served astronomers and navigators throughout history, allowing them to make astronomical observations and navigate the seas. While the quadrant laid the foundation for angular measurement devices, the sextant evolved as a more refined and accurate instrument, enabling precise calculations for navigation.

While both sextant and quadrant are used for measuring angles, they are different in their ranges and applications. A sextant can measure angles up to 120 degrees due to the double reflection, making it versatile for various navigational needs, while a quadrant is limited to measuring 90 degrees. The more modern and precise sextant offers more reliable readings and has been a staple in celestial navigation, whereas the quadrant, with its historical significance, represents the evolution of measuring instruments in astronomy and navigation.

The differences between a sextant and a quadrant are not just in their construction and range but also in their applications and significance in the history of navigation and astronomy. The sextant, being more advanced, is still relevant in modern navigation, while the quadrant stands as a testament to mankind’s early endeavors in understanding the cosmos and navigating the vastness of the seas. Both instruments, with their unique features and capabilities, have contributed immensely to advancements in navigation and astronomical observations.

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## Comparison Chart

### Definition

An instrument measuring angular distances.

An instrument measuring altitudes or a quarter of a circle.

### Construction

Has a small movable telescope attached to the frame.

Typically consists of a quarter-circle plate and a plumb line.

### Range

Measures up to 120 degrees.

Measures up to 90 degrees.

### Historical Significance

Enabled long ocean voyages and exploration.

One of the oldest astronomical instruments used for navigation.

### Applications

Mainly used for celestial navigation.

Used in astronomy and navigation to determine position at sea.

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## Sextant and Quadrant Definitions

#### Sextant

A sextant is a navigational instrument used to measure the angular distance between two visible objects.

The mariner used a sextant to determine the ship's latitude by observing the sun.

#### Quadrant

The ancient navigator used a quadrant to observe the stars and determine his position at sea.

The quadrant is a testament to mankind’s early efforts in navigating seas and understanding the cosmos.

#### Sextant

The sextant is crucial for celestial navigation, enabling precise calculations of geographic location.

The aviator relied on a sextant to navigate across the vast, unmarked ocean.

#### Quadrant

It is a historical tool that consists of a quarter-circle plate and a plumb line to measure vertical.

The quadrant revealed the angles necessary for the astronomer to understand celestial alignments.

#### Sextant

It is a device featuring a small telescope and an arc measuring up to 60 degrees.

With a sextant, sailors can navigate accurately by measuring angles between celestial bodies.

#### Quadrant

The quadrant is an ancient measuring device used extensively in astronomy and navigation.

With the quadrant, early sailors were able to navigate the seas and explore new lands.

#### Sextant

It allows the user to observe celestial objects and derive accurate angular measurements.

By utilizing a sextant, explorers were able to traverse and map uncharted territories.

#### Quadrant

A circular arc of 90°; one fourth of the circumference of a circle.

#### Sextant

A sextant is renowned for its precision and reliability in navigational measurements.

The sextant provided the crucial navigational data needed during the long ocean voyage.

#### Quadrant

The plane area bounded by such an arc and two perpendicular radii.

#### Sextant

A navigational instrument containing a graduated 60-degree arc, used for measuring the altitudes of celestial bodies for use in determining the latitude and longitude of the observer.

#### Quadrant

Any of the four areas into which a plane is divided by the reference axes in a Cartesian coordinate system, designated first, second, third, and fourth, counting counterclockwise from the area in which both coordinates are positive.

#### Sextant

Sextant See Sextans.

#### Quadrant

A machine part or other mechanical device that is shaped like a quarter circle.

#### Sextant

(nautical) A navigational device for deriving angular distances between objects so as to determine latitude and longitude.

#### Quadrant

An early instrument for measuring altitude of celestial bodies, consisting of a 90° graduated arc with a movable radius for measuring angles.

#### Sextant

(geometry) One sixth of a circle or disc; a sector with an angle of 60°.

#### Quadrant

One of the four sections made by dividing an area with two perpendicular lines.

#### Sextant

(dentistry) One of six groups of adjacent teeth, excluding the wisdom teeth. The front sextants go from canine to canine, and there are sextants on the right and left of these. See w:Periodontal examination.

#### Quadrant

(mathematics) One of the four regions of the Cartesian plane bounded by the x-axis and y-axis.

#### Sextant

The sixth part of a circle.

#### Quadrant

(geometry) One fourth of a circle or disc; a sector with an angle of 90°.

#### Sextant

An instrument for measuring angular distances between objects, - used esp. at sea, for ascertaining the latitude and longitude. It is constructed on the same optical principle as Hadley's quadrant, but usually of metal, with a nicer graduation, telescopic sight, and its arc the sixth, and sometimes the third, part of a circle. See Quadrant.

#### Quadrant

(nautical) A measuring device with a graduated arc of 90° used in locating an altitude.

#### Sextant

The constellation Sextans.

#### Quadrant

(college basketball) One of the four categories of team wins and losses, as categorized by strength of schedule.

#### Sextant

A unit of angular distance equal to 60 degrees

#### Quadrant

(obsolete) A square or quadrangle.

#### Sextant

A measuring instrument for measuring the angular distance between celestial objects; resembles an octant

#### Quadrant

The fourth part; the quarter.

#### Quadrant

The quarter of a circle, or of the circumference of a circle, an arc of 90°, or one subtending a right angle at the center.

#### Quadrant

One of the four parts into which a plane is divided by the coördinate axes. The upper right-hand part is the first quadrant; the upper left-hand part the second; the lower left-hand part the third; and the lower right-hand part the fourth quadrant.

#### Quadrant

An instrument for measuring altitudes, variously constructed and mounted for different specific uses in astronomy, surveying, gunnery, etc., consisting commonly of a graduated arc of 90°, with an index or vernier, and either plain or telescopic sights, and usually having a plumb line or spirit level for fixing the vertical or horizontal direction.

#### Quadrant

A quarter of the circumference of a circle

#### Quadrant

A quarter of the circumference of a circle

#### Quadrant

Any of the four areas into which a plane is divided by two orthogonal coordinate axes

#### Quadrant

The area enclosed by two perpendicular radii of a circle

#### Quadrant

A measuring instrument for measuring altitude of heavenly bodies

#### Quadrant

A quadrant is an instrument used to measure the altitude of celestial objects or can represent one-fourth of a circle.

The quadrant found in the ancient shipwreck was likely used to measure the altitude of the stars.

#### Quadrant

The astronomer employed a quadrant to conduct various celestial observations.

It allows the measurement of angles up to 90 degrees and has historical significance in navigation.

## FAQs

#### What is a sextant primarily used for?

A sextant is primarily used for measuring angular distances between objects, mainly in celestial navigation.

#### Is the quadrant limited to measuring celestial objects?

While historically used for celestial objects, it can measure any vertical angle within its range.

#### Are sextants complicated to use?

They require knowledge and practice as they involve precise measurements and calculations.

#### Is a quadrant still used in modern navigation?

The quadrant is largely obsolete in modern navigation, replaced by more advanced instruments.

#### Is a sextant portable?

Yes, sextants are portable and are often carried by navigators and sailors.

#### Are sextants expensive?

High-quality sextants, especially antique ones, can be quite expensive due to their craftsmanship and precision.

#### Can a quadrant be made of different materials?

Yes, quadrants have been made from various materials including wood, brass, and other metals.

#### Is a sextant’s accuracy affected by the motion of a ship?

Yes, the motion of the ship can affect readings, and experienced users account for this when taking measurements.

#### Does the quadrant have a telescope like the sextant?

Typically, no. Quadrants are simpler, consisting of a quarter-circle plate and a plumb line.

#### Are quadrants only quarter-circles?

In geometry, yes. But as a navigational tool, it refers to the instrument used to measure vertical angles.

#### Can both instruments determine latitude and longitude?

Both can help determine latitude, but determining longitude typically requires additional information and tools.

#### Can a sextant measure more than 60 degrees?

Yes, a sextant can effectively measure up to 120 degrees due to the principle of double reflection.

#### Was the quadrant used before the invention of the sextant?

Yes, the quadrant is an older instrument and predates the invention of the sextant.

#### Can these instruments be used by amateur astronomers?

Yes, both sextant and quadrant can be used by amateur astronomers for learning and observation purposes.

#### Do both sextant and quadrant require clear skies?

Clear skies are preferable for accurate readings as celestial bodies need to be visible.

About Author

Written by

Janet WhiteJanet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.

Edited by

Harlon MossHarlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.