Sextant Model For Angles And Heights

Sextant Model for School Maths Lab

Integrated Dual-Mirror System: Demonstrates the physical principle of double reflection, allowing students to analyze how light path geometry dictates angular measurement.

Sliding Index Arm and Graduated Arc: Facilitates the collection of raw vertical angle data, enabling students to apply the Law of Sines and Law of Cosines in real-world height calculations.

₹354.00

Quick Answer: A Sextant Model is a teaching model of the sextant, a navigation instrument that measures the angle between two objects, such as the sun and the horizon, by bringing the image of one into line with the other using two mirrors. Maths classes use the sextant model to study angle measurement, angles of elevation and height-and-distance problems.

How a Sextant Measures an Angle

A sextant has a frame carrying an arc of about one sixth of a circle, which gives the instrument its name, and a pivoting index arm with a mirror at its upper end. A second mirror, the horizon glass, is fixed to the frame and only partly silvered. Looking through the sight at the horizon, the user moves the index arm until the reflected image of the sun or a star sits on the horizon line, then reads the angle from the arc.

Because the light is reflected twice, turning the index mirror through an angle turns the reflected beam through twice that angle. The arc is therefore marked with doubled values, so an arc of about 60° reads angles up to about 120°. This is the same double-reflection rule used in the optical square, and it makes a good bridge between geometry and optics.

In a maths lab the model is mainly used for angles of elevation. Measuring the angle to the top of a flagpole or building from a known distance, students calculate its height with the tangent ratio, height = distance × tan θ, then add the observer’s eye height. A teaching model must never be pointed at the sun; construction and scale should be confirmed with LabEquip.

Care & Handling

Never point the model at the sun, because a teaching model may have no protective shade glasses.
Keep both mirrors clean and dry, and avoid touching their silvered surfaces.
Carry and store the model in its box, holding it by the frame rather than the index arm.

Applications

Measuring angles of elevation to tall objects and calculating their heights
Showing the double-reflection principle with a light source in class
Explaining how navigators found latitude from the altitude of the Pole Star
Comparing the sextant with a clinometer for measuring vertical angles

Specifications

Item	Teaching model of a navigational sextant
Principle	Double reflection: the arc reads twice the angle turned by the index mirror
Main class uses	Angle measurement, angles of elevation, heights and distances
Typical level	Secondary trigonometry; vocational navigation and surveying introductions
Construction and scale	Confirm at enquiry

Why Choose LabEquip

Schools teaching heights and distances often pair this model with a Clinometer Compass for quick elevation readings and the Optical Square Model for right angles on the ground. LabEquip lists these in its Mathematics School Lab Products range.

Frequently Asked Questions

Why is it called a sextant?

The graduated arc of the instrument is about one sixth of a full circle, roughly 60 degrees, and sextans is Latin for a sixth part. Because of double reflection, that arc measures angles of up to about 120 degrees.

How can a sextant be used to find the height of a building?

Stand a measured distance from the building and measure the angle of elevation to the top. The height above eye level equals the distance multiplied by the tangent of the angle, and adding the observer’s eye height gives the full height. At 20 m and 45 degrees, the height above eye level equals 20 m.

What is the difference between a sextant and a clinometer?

A clinometer measures the tilt of a line of sight against the vertical or horizontal using gravity, a pendulum or a bubble. A sextant measures the angle between two objects seen together through mirrors, which is why it could be used on a moving ship.

Is it safe to look at the sun through a sextant model?

No. Real navigational sextants have dark shade glasses for sun sights, and a teaching model may not. Students should only sight buildings, trees, flagpoles or similar objects, never the sun.

What is meant by the angle of elevation?

It is the angle between the horizontal and the line of sight upward to an object. If the observer looks down instead, the angle below the horizontal is the angle of depression. Both appear in height and distance problems.

Which lessons use a sextant model?

It suits secondary trigonometry lessons on heights and distances, practical geometry outdoors, and physics lessons on reflection. It also introduces the history of navigation, when latitude was found from the altitude of the sun or the Pole Star.

Last Updated: September 2026