How to Describe a Sextant

A sextant is a device used by mariners for navigation. Since GPS has largely superseded the use of the sextant -- and since most people are not sailors -- the use of the sextant is mysterious to most people. If you can describe a this well, your listener will have a good understanding of what a sextant is and how it works. It is even possible that, following a good explanation, the person will be able to use it the first time she lays her hands on one.

Instructions

    • 1

      Describe the basic purpose of a sextant, which is to find the angle between two points. Usually these two points are the sun and a point on the horizon.

    • 2

      Describe the construction of a sextant. A basic sextant includes two mirrors. One is completely reflective and attached to a moveable arm which slides along an arc-shaped base. The other mirror is partially see-through and fastened to one end of the base. At the other end of the base is the eyepiece.

    • 3

      Describe the use of a sextant. The user looks through the eyepiece at the horizon, so the horizon is visible through the see-through mirror. The light from the sun reflects off of the first mirror. The user adjusts the arm so both the horizon and reflected sun are visible in the see-through mirror. The user then reads the angle off the scale.