What is a sextant?
It looks like something from a Jules Verne novel – but this tool is pure nonfiction.
Long before GPS and other electronic tools took over in navigation, ship captains had to measure their location differently.
That’s where the sextant comes in. It looks complicated to modern eyes, but navigators were experts at each technical part. How does a sextant work? At the most basic explanation, a sextant measures the altitude of the sun or other celestial bodies above the horizon. It uses two mirrors; you look through one mirror at the horizon, while the other mirror moves on an arm to where the sun reflects off of it. Then the angle is read on the scale. This information is used to find the boat’s position on a chart.
The sextant is still sometimes considered an excellent backup on a ship for navigation, since unlike most modern navigational tools, it doesn’t run on electricity. It’s also a very accurate tool.
The sextant in the pictures is from 1837. It’s in remarkable condition and is even in its original box.
The label (a very pretty label, if only they made them like that today!) says: “the Sextant No. 19595 named Henry Hughes & Son LTD. of 6” radius & reading to 10” has been examined & found satisfactory.”
This site has a fun project to build your own sextant!