Looking at some sextants because who knows what if the batteries give out on your GPS, right? I know it’s not a popular option, most navigators just buy a second or even third GPS before getting a sextant. Because apparently not only is math hard, but a sextant is a precision instrument and they go for a lot more than a silly gps.

The precision is not bad tho, for a device which is a glorified protractor. All it can do is measure the angle between two objects, but it can do so at the precision of a 1 minute or so (one minute is a 60th of a degree). Since one nautical mile is one minute that is a pretty decent accuracy.

Hardly anyone makes sextants tho, and it is painful to look at some of those so called sextants which are basically art objects you can put on the shelf, the mirrors are not even adjusted.

Here is one classy sextant the Tamaya Jupiter:



This one is ridiculous, 20 seconds of arc!  Nice telescopes, solid precise instrument here.   60 seconds in 1 minute so that is being able to measure where you are on the planet down to 600 yards.    It has a premium price, tho $1,900.

I think the single most popular sextant right now is the Davis Mark 3, a simple plastic sextant.  The plastic tho, it can get knocked out of alignment pretty easy.


$45.  No telescopic sight.  The upscale Davis is the one with a telescope, the Davis Mark 15




One bad thing about the marine sextants is that if you want to use them on land you need some sort of level.  A common thing to add is a little device full of water, which gives you the artificial horizon, it’s a little triangular bucket that you can add to these sextants.  Normally you would fill it full of water, but if it’s 40 below you would want to add some other liquid.



Before the advent of gyroscopic navigation, and GPS’s, back in the day, aircraft used something called a “Bubble Sextant”.  Basically it was a regular sextant with a little carpenter’s bubble that  you used to take your reading from.  Aircraft were so far above the horizon that using it to measure your angle was not possible.


Here is a bubble sextant in the case still, not assembled.



Naturally all the spirits have long evaporated, so I would have to refill the bubbles, but you can get a used sextant like this for under $100.


There are all kinds of used sextants out there.  But you have to bid for them against collectors, not someone that wants to get a backup for their GPS.


Here is a beautiful astra iiib on ebay, several hundred dollars