Sextants?

[Matthew]

I stumbled across a picture of a sextant yesterday and now I’m interested.

Is there any such thing as a low cost beginner sextant?

 

[Dana]

Yes.

 

[MauleSkinner]

I think I’ve still got one of these that I’d make you a deal on…

Davis Mark 3 Sextant

This sextant will enable the beginner to learn and practice the rudiments of celestial navigation at the lowest possible cost. It is made of heavy gauge plastic with an adjustable half mirror (which is equivalent to a traditional half silvered mirror).

www.celestaire.com

 

[Sac Arrow]

I guess as long as you can still get a Nautical Almanac in print, it will still be useful.

 

[Sac Arrow]

Oooh, what a concept. If GPS fails, you can fall back on this....

The Stars Return: Draper Patents Celestial Navigation System

Scientists at Draper Laboratory have patented a celestial navigation system called a sliced-lens star tracker, which in its early form can achieve 50-meter accu

insidegnss.com

 

[wanttaja]

I bought the sextant on the left at one of those "Things Remembered" nicknack stores.

It appears to be fully functional, though it was missing a screw on the back. IIRC, I paid about $100 for it ~20 years ago, and it came in a nicely-finished oak box.

On the right is a WWII aircraft sextant, bought at an antique shop for about $100 as well. I actually use it as the base for my 3-D printed gunsight.


"Do you sell sextants?"

"WHAT kind of tent?????"

Ron Wanttaja

 

[Matthew]

I was just looking at a sextant manual. I remember reading a book called “Longitude”, about the need to invent a chronograph for more accurate navigation.

 

[MauleSkinner]

I guess as long as you can still get a Nautical Almanac in print, it will still be useful.

Good news is that there are enough sailors doing Celestial Nav that the necessary documentation probably won’t go away in my lifetime.

 

[Tools]

HO 449. Far easier than the HO 249 us ship drivers used…

Don’t know if I’d trust me though, think I got a D in that class. Simple mistake early in the final cascaded through the whole thing. No “correct for data”. Yikes.

Prof was Japanese navy on exchange. Couldn’t understand a damn thing he said except: cestial nababation

 

[RussR]

I was just looking at a sextant manual. I remember reading a book called “Longitude”, about the need to invent a chronograph for more accurate navigation.

I read that book and found it fascinating.

 

[kyleb]

Prof was Japanese navy on exchange. Couldn’t understand a damn thing he said except: cestial nababation

I think I had that exact same guy for 5 years at Georgia Tech!

 

[ja_user]

Brings a new meaning to "non precision approach"

 

[asicer]

Low cost?

SEXTANT fully functional by Bodek152

Functional sextant with vernier scale precision of 6' (6 geographical minutes).For sun protection shields I used a standard spare glasses for welding mask.Mounting screws are M3 and for sun shields M4.I used 3mm glass mirrors, but they are not the best because of light refraction error in glass...

www.thingiverse.com

 

[Matthew]

Brings a new meaning to "non precision approach"

It works great in IMC. Toss it out the window and follow it down.

 

[Iflydogs]

If you don’t have a Nautical Almanac, just shoot the pole star, that will give you latitude within 60 nm. Sailors used it for millennia, it was called latitude sailing, they shot the pole star each night, if it was climbing they were heading a bit north and corrected and vice versa. The Polynesian sailors used a coconut filled with oil and holes that aligned to the latitude they wanted to be at.

If you have an accurate timepiece and shoot local apparent noon on each sides of LAN, fair a curve through through your sightings and you will have a good measurement of longitude.

 

[eman1200]

 

[Matthew]

I guess that’s one way of shooting the pole star

 

[MauleSkinner]

Sorry, @Matthew , looks like I got rid of my sextant at some point already.