sextant??

[Bill NH]

Funny how things happen...  Just after this thread, I was at a "social gathering" the other night where a few other sailors were in attendance.  We got talking sextants and one guy says he bought a Davis Mk3 sextant to take a class but hasn't used it since.  I ended up swapping him a case of beer for it, not that I need one but thought there might be interest here...  now listed in the SellFar section - no personal profit, just want to get my case of beer back.   ;D

[s/v Faith]

Bill,

  Enjoy a grog for your trouble.  Thanks for thinking of everyone here (or at least whoever winds up with it).   ;D

[Oldrig]

FWIW, after this discussion (plus some PMs with Chris), I took my 1904 Heath of London sextant out of its case and looked at it carefully.

My conclusion: If I ever want to do celestial navigation on a boat, I'm going to need a newer instrument, probably a Davis Mark 15.

Back when I was a student (my 40th college reunion is this spring), I had little trouble reading an old-style vernier index. But that was on land and before I got glasses. This kind of sextant is probably fine for use on the deck of a large ship--in relatively calm weather. But my older eyes had a very tough time reading the index.

Shackleton probably used a similar sextant, in a lifeboat no less, but I have no illusions about comparing myself to such a great seaman and navigator.

--Joe

[SeaHusky]

Picking up an old thread,
If I am able to get a good deal on an old sextant and intend to use it both for learning and for actual use on a small boat, should the vernier versions be avoided in favor of micrometer?

[ntica]

I bought a Frieberger sextant some years ago. Warnings for second hand, if you can't check them first. mine had an index error of "to much" , would cost a great deal to get fixed.

[SeaHusky]

Thanks!
Perhaps the best choice is a Davis MarkIII with an artificial horizon until I am proficient enough to make an informed decision.

[gpdno]

I just bought a Davis Mark 25 on ebay.  My first sextant :)  I have a 5 week celestial navigation class starting in a few weeks, can't wait ;)

[Oldrig]

Picking up an old thread,
If I am able to get a good deal on an old sextant and intend to use it both for learning and for actual use on a small boat, should the vernier versions be avoided in favor of micrometer?

The micrometer is generally preferred over the older vernier scale. When I was studying celestial navigation in college, more than 40 years ago, we practiced on vernier sextants--and I bought one of them from the university. It's a beautiful artifact, more than 100 years old, but I'd have a hard time trying to read that scale, especially on a pitching SailFair-type boat. (My eyes aren't what they were as a student, and we only practiced on land.)

I'd suggest looking for a Davis plastic sextant, if you want to go cheap. There's even a book, written by David Burch at StarPath (www.starpath.com) that specifically discusses getting fairly accurate fixes with a plastic sextant. Here's a link to the relevant chapter of that publication:

http://www.starpath.com/online/celestial/plastic.pdf

Please note: I bought a Davis plastic sextant at a very good price from our own Kurt (Cap'n. K), but I have yet to practice using it. My own coastal waters have very limited clear horizons, but it's on my long to-do list.

Good Luck,

--Joe

[jpfx]

I also have a davis mk. 25 from ebay. It seems to be in pretty good condition though one of the mirror clips had snapped. I bought spare ones from davis instruments.

I'm not sure if I would prefer the mk. 15 with the half silvered mirror as opposed to the beam converger. I've only tried the mk.25 and there's not much opportunity to test drive others. The astras, freibergers, plaths and tamayas that appear on ebay are very tempting though.

I'm building a fair collection of books on the subject too. None have stood out as THE tome to have. My biggest hurdle is getting all the jargon into my head such that it I understand the concepts being explained. It's coming slowly, more through repetition than 'eureka' moments.

[Captain Smollett]

I just bought a Davis Mark 25 on ebay.  My first sextant :)  I have a 5 week celestial navigation class starting in a few weeks, can't wait ;)

I'm building a fair collection of books on the subject too. None have stood out as THE tome to have. My biggest hurdle is getting all the jargon into my head such that it I understand the concepts being explained. It's coming slowly, more through repetition than 'eureka' moments.

I haven't finished it yet, and I really did not ever intend it to be a replacement for a good book or an actual course on CN, but I did start this thread on celestial navigation a while back.

[SeaHusky]

Thanks! Oldrigs link was very enlightening as to the limitations or rather extra work necessary with the plastic sextant.
Is an artificial horizon worth having as a learning aid?

[Captain Smollett]

Is an artificial horizon worth having as a learning aid?

I think so.  I've used mine for practice quite a bit, especially when we lived inland...way inland.

It is my opinion that using a sextant is not something that can be mastered from reading it once in a book.  I think a lot of GPS-but-have-a-sextant-as-back-up sailors do this...buy a sextant and the site reduction tables, along with a book (or index card) describing the basic procedure and thing they are good.

I disagree.  I think it requires hands-on practice with the sextant to get good at taking sights.  Without good data from the measurement, all the calculators and tables in the world won't make a good fix.

And using the sextant well, while not hard per se, is harder than it seems from most 'book definitions.'

The more you practice, the better you will get.

My half-cent.

[Oldrig]

And using the sextant well, while not hard per se, is harder than it seems from most 'book definitions.'

The more you practice, the better you will get.

John,

I couldn't agree with you more!
In the words of Hewitt Schlereth, author of Celestial Navigation in a Nutshell:

"Learning to use a sextant is a lot like learning to shoot a rifle. ... You can read about celestial navigation till the cows come home, but you won't learn it until you do it."

--Joe

[rorik]

Dunno if this helps...... but fwiw......   
http://www.landfallnavigation.com/kcnb.html

[ntica]

Today I got an offer to buy a Zeis sextant, new and never used. anyone any info on it? asking 900USD resonable???

[SeaHusky]

Just to clarify, isn't it the east german "Zeiss Jena" manufacture?

[ntica]

found out. used by the russian marine...Recommended among sailing community. as far as I can see...

[SoloBob]

I feel I need to jump in here.....

I'm pretty old school, and even though I may have a number of GPS devices,  I'm always going to have my trusty sextant aboard. To keep in practice, I still use it to double check the electronics. 

If your not in a huge hurry, be patient, watch Ebay.. do up a saved search.  "Watch" the ones that are of interest to you, set yourself a fixed price of what you want to spend, and don't bid over your preset limit.  If you loose this one, another will come along.   I know 2 people in the last year, that have come away with real deals.  One with a nice Tamaya for $400, and a MAC for $305.   

For the most part, as long as it's a name brand device, the mirrors and optics are intact, the quadrant isn't bent, with the original certification in the box, your good to go. 

It's been my experience, most of us tend to like the style of sextant we originally learned on...

Even though Starpilot has a fantastic program for the TI-89 calculator ( and I do have one  ;) ) , I recommend always having the proper reference materials on board.. so when the GPS fails, and you can't find a couple of good AAA batteries in the Galley... you can still get a clue about which Ocean you're in.  ;D

Cheers
Bob

[Captain Smollett]

Good suggestion, Bob. That's why I carry a slide rule in my nav kit.  ;D ;) ;D

[ntica]

Found another not that expensive one... But the seller dosn't know what "brand" the text is in Russia... anyone knows? suggestion of bying? 
it's from 1983.