Re: Sextant Purchase

[Santeh]

Re: Sextant Purchase

Hello all,

I am new to the sextant world, yet in one of the college courses I teach there is a small section on celestial navigation, of which the sextant is described and used. Unfortunately my college has some very, very cheap sextants (hard to even call them that as there is no micrometer drum, clamps, or even true telescope) that I find very hard to try and work with. I was therefore thinking of getting a real sextant so that I can both learn how to effectively use the device, as well as show my students what a true sextant is about.

I was therefor wondering what kind if sextant you all might suggest? I have been eyeing some Tamayas, yet if this might be a good type are there any models that I should focus on (thus also those to avoid)? If a Tamaya is not an appropriate choice, then what might be a good one for my purpose? I was hoping to spend $200-300US or so if possible.

Also, out of curiosity what does MAC mean in regards to sextants?

Thank you all for your suggestions!

 

[Neil]

Probably the cheapest 'real' sextant is the Astra IIIb, but that is still out of your range, new. So second hand is the way to go - keep an eye on ebay, but 'ware of the the ornamental ones. A genuine, Tamaya, Plath, Freiberger, you can't go far wrong. Not sure about MAC........

 

[sarabande]

best kit for teaching use is the Davis

http://www.starpath.com/catalog/accessories/1840d15.htm

MAC is a make of sextant.

 

[Santeh]

Probably the cheapest 'real' sextant is the Astra IIIb, but that is still out of your range, new. So second hand is the way to go - keep an eye on ebay, but 'ware of the the ornamental ones. A genuine, Tamaya, Plath, Freiberger, you can't go far wrong. Not sure about MAC........

Hello!

Thank you for the reply! I appreciate it!

I am indeed watching eBay and if what I have seen the Tamayas look decent and possibly applicable for what I am attempting to do. How do I know what I genuine version (model) if a Tamaya, Plath, and Freiberger might be?

 

[Santeh]

best kit for teaching use is the Davis

http://www.starpath.com/catalog/accessories/1840d15.htm

MAC is a make of sextant.

Hello!

Thank you! The price of this sextant is certainly in my range. However, and please forgive my ignorance, but is a plastic sextant okay? What might a metal sextant offer that a plastic one does not?

 

[Santeh]

What models of Tamaya are considered "good"?

 

[Neil]

Ones that haven't been dropped down the companionway.......

 

[Santeh]

Ones that haven't been dropped down the companionway.......

yep, I like Tamayas too (what little I know of them).

 

[nigelmercier]

What might a metal sextant offer that a plastic one does not?

The potential to corrode. I've got a Frieberger, but I don't dare take it on the boat.

 

[sarabande]

:sigh: if you are teaching sextant work to new users, the last thing you need is for some cack-handed tyro to drop 500 squids worth of metal work even a few inches onto a desk.

Plastic sextants may not a superlatively accurate as a proper metal one, but the principles are there, and they DO work properly, i.e will give you a decent position line. If you learn to drive a plastic one, you can drive a metal one.


I take it you have never handled a sextant, yet you want to teach it ???

 

[AndrewB]

Hello!

Thank you! The price of this sextant is certainly in my range. However, and please forgive my ignorance, but is a plastic sextant okay? What might a metal sextant offer that a plastic one does not?

Yes, but only if its a good one. As recommended before, look at a Davis Mk 15, which is in your price range. Not as accurate as the better metal ones, but I navigated across a couple of oceans with mine.

 

[Santeh]

:sigh: if you are teaching sextant work to new users, the last thing you need is for some cack-handed tyro to drop 500 squids worth of metal work even a few inches onto a desk.

Plastic sextants may not a superlatively accurate as a proper metal one, but the principles are there, and they DO work properly, i.e will give you a decent position line. If you learn to drive a plastic one, you can drive a metal one.


I take it you have never handled a sextant, yet you want to teach it ???

As long as the plastic version is adequate for teaching that is fine, then.

In regards to teaching, in this case want does not have much to do with it as it is part of the course itself which is a college level earth science class. Correctly, then, the course has a component of astronomy yet celestial navigation happens to have been included. And, while in all my science training sextants were never there (even during my undergraduate work in marine science), I now have to self teach it so that I can properly introduce the subject and let the students try. To this latter point, the students get to use the cheap plastic ones my college has and I will allow one person-at-a-time, with me present, to try my real one. The lesson just needs to be scientifically accurate and procedurally correct.

Yes, but only if its a good one. As recommended before, look at a Davis Mk 15, which is in your price range. Not as accurate as the better metal ones, but I navigated across a couple of oceans with mine.

I will definitely look into it, then. Thank you!

 

[Uricanejack]

Hello all,

I am new to the sextant world, yet in one of the college courses I teach there is a small section on celestial navigation, of which the sextant is described and used. Unfortunately my college has some very, very cheap sextants (hard to even call them that as there is no micrometer drum, clamps, or even true telescope) that I find very hard to try and work with. I was therefore thinking of getting a real sextant so that I can both learn how to effectively use the device, as well as show my students what a true sextant is about.

I was therefor wondering what kind if sextant you all might suggest? I have been eyeing some Tamayas, yet if this might be a good type are there any models that I should focus on (thus also those to avoid)? If a Tamaya is not an appropriate choice, then what might be a good one for my purpose? I was hoping to spend $200-300US or so if possible.

Also, out of curiosity what does MAC mean in regards to sextants?

Thank you all for your suggestions!

If you are serious and want an old Tamaya, (not to be used for navigation). but good enough for demonstration of principle. let me know where you are and what you are teaching.

you won't find a decent sextant for 200 or 300.
you might find a good Frieberger for 500

 

[Santeh]

If you are serious and want an old Tamaya, (not to be used for navigation). but good enough for demonstration of principle. let me know where you are and what you are teaching.

you won't find a decent sextant for 200 or 300.
you might find a good Frieberger for 500

Hello!

Thank you! This was a most kind offer. However after reading all the comments here, and before you wrote this message, I was able to pick-up a 1973 Tamaya model 635-S marine sextant. I am very excited as I have read that the 635 model is a solid sextant which should work well for my intended purpose.

Thank you again, though. And, quite, thank you all for your comments and suggestions!

 

[oldvarnish]

you won't find a decent sextant for 200 or 300.
you might find a good Frieberger for 500

That's about right. I got a nice Plath for £350 on ebay and thought it was a good buy.

 

[lustyd]

I always thought plastic was actually superior for use in this type of thing since it's unaffected by heat and won't corrode. The metal ones are pretty but I can't see how they would give a more accurate reading just through the magic of being metal.

 

[Neil]

I always thought plastic was actually superior for use in this type of thing since it's unaffected by heat and won't corrode. The metal ones are pretty but I can't see how they would give a more accurate reading just through the magic of being metal.

The Davis 15 looks good in photos and I've read good things on this forum. However, how are they made? are the plastic bits just moulded, moulded and then machined, or what? I'm just guessing that you can get finer tolerances from machined metal? Any materials scientists out there?

 

[AndrewB]

Hello!

Thank you! This was a most kind offer. However after reading all the comments here, and before your wrote this message, I was able to pick-up a 1973 Tamaya model 635-S marine sextant. I am very excited as I have read that the 635 model is a solid sextant which should work well for my intended purpose.

Do hope it has in-date certification. It's a risk buying a second-hand sextant this old, too often they've had an accident and are knackered, which won't be obvious without proper testing. If you are expecting to use it for real navigation, get it professionally tested asap, or at least ask someone well experienced in taking sights to check that it's accurate.

 

[lustyd]

The Davis 15 looks good in photos and I've read good things on this forum. However, how are they made? are the plastic bits just moulded, moulded and then machined, or what? I'm just guessing that you can get finer tolerances from machined metal? Any materials scientists out there?

You may get finer tolerances at manufacture but metal changes size with heat so they are meaningless

 

[oldvarnish]

You may get finer tolerances at manufacture but metal changes size with heat so they are meaningless

So those sextant makers have been getting it wrong all these years?