Octant (instrument)

High school (ages 12+)
Science & Technology

Name:

Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/octant-instrument

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. What is the scientific principle?Utilizes the double reflection of mirrors to measure celestial altitudes
2. What is the arc measurement?Typically 45 degrees, allowing measurement of angles up to 90 degrees
3. What is an octant and how does it help sailors?An octant is a small reflecting instrument that lets sailors measure the angle between a star or the sun and the sea horizon. By reading this angle, they can find their latitude and know where they are on the ocean.
4. How does the octant use mirrors to measure angles?The octant has a movable arm with a mirror that reflects a star or the sun to a second horizon mirror. When the reflected image lines up with the horizon, the angle on the arc shows twice the altitude of the celestial body.

Celestial Altitude: The angular height of a celestial object above the horizon, measured in degrees.
Reflecting Instrument: An optical device that uses mirrors to direct or measure light.
Geodesy: The scientific discipline that deals with the measurement and representation of the Earth.