Bris Sextant - Who can make?

[Kevin McCready 83]

I spoke to Sven Yvind a few days ago. He wanted EUR200 to make me one. Maybe that's a fair price. I don't know.

 

Can any of you smart chaps make me one for half that price or less?

 

I'm pretty sure he'd be happy to help with any technical details.

 

Who knows, you could make hundreds and go into a new line of business.

 

http://www.yrvind.com/present_project/?p=1225

 

https://www.google.com/search?q=site%3Ayrvind.com+MINISEXTANT&gws_rd=ssl

[erice 732]

[erice 732]

presumably the least important specification is the area of the glass, it's small for convenience

 

so materials needed are just a strip of 11mm 1.5mm clear glass and a tiny bit of 2.5mm dark filter glass (darker? than arc welding filter)

 

then a carbide glass cutter, a bit of time in the garage trying to cut 3 blocks to size and any epoxy + for the 2 spacers, strips of wood or plastic............maybe also a diamond file to dress the edges

 

that would be enough for a test rig

 

drop in to a glass cutter and see what sort of off-cuts they would swap for beer 

[banaari 27]

Concur.

Given the current strength of the $NZ vs the Euro, the price asked wouldn't be unreasonable, especially if Sven will do the calibration for you.

BUT I rather suspect you're supposed to make your own

[Romany 162]

So - is it a navigational toy (as he describes it) or a precision instrument? - see http://www.yrvind.com/sextant_read_more.html

[Pumbaa 9]

That is brilliant, I love stuff like that, some people know how to think. Plus I want one, I sold my sextant in back 1990, I should have kept it but I haven't actually needed it since either.

As for it being a toy or an instrument, you'd need to accurately know the angle it refracts at and then with the time you're home and hosed. So I would say it's an instrument, if you know the angle, if you don't then it's just junk.

[NevP 0]

That is brilliant, I love stuff like that, some people know how to think. Plus I want one, I sold my sextant in back 1990, I should have kept it but I haven't actually needed it since either.

As for it being a toy or an instrument, you'd need to accurately know the angle it refracts at and then with the time you're home and hosed. So I would say it's an instrument, if you know the angle, if you don't then it's just junk.

I haven't used/seen one but I'd say it's definitely an instrument if it works as described.

 

No need to measure the angles of the glass plates. The idea is that you calibrate it by taking a set of observations (or several) from a known location and then you work everything backwards to determine the angles observed. You then use the 'calibrated' angles for all your future observations.

 

Awesome example of KISS. You'll still need a set of solar tables and an accurate time piece handy though.

[Pumbaa 9]

I've no idea how much sight reduction tables cost anymore but you can get good time from the gps  . Or back in the olden days we used to get it from the sat nav. Digital watches and crystal time keeping was around for quite a while and you could get a time update from the radio. I feel so oldey timey.

We were out the other day and i think we had 4 phones with gps and charts, 2 tablets with gps one with charts, 1 laptop with charts and gps and the only dedicated gps item-a handheld garmin with only lat and long. A total of 8 accurate  position indicators and these are all literally thousands of times more accurate than the sat navs I first used which were on a par with my celestial abilities, which were more or less accurate give or take 2 to 12 miles or so.

[NevP 0]

And all this probably relegates the Bris Sextant (along with the real sextants) to not much better than a toy today. Even as a backup, by the time we have managed to destroy all the electronic navigation on board, what are the chances that we would still have intact (soggy?) reduction tables and a working time piece on board?

 

I do like the idea of learning the traditional nav methods but it doesn't really seem like it has a practical use any more other than as an interesting hobby.