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  #1  
Old 01-19-2012
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Not a war, just a sextant question.

Seriously, I'm just curious:

On E-bay I can buy a Davis plastic sextant for anywhere from 40 to 120 dollars depending more on model than condition.

Would I really be that much farther ahead to do that than to buy a metal replica that I could "tweak" for around 60 to 80?

At this point, a small consistent error is something I could live with as I'm not planning to dock my boat with it. To help with my point, I'm currently using a non WAAS enabled gps. The way I see it is that as long as I'm using the correct datum, my gps is still more accurate than a pencil dot on a 1:50,000 topo map, and I'm good with that. While unaware that I was using the wrong datum in one circumstance I still managed to extrapolate my actual position.
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Old 01-19-2012
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I think that it can be fun to use a sextant but for positioning it is really very inaccurate. If you get within a mile have done well - and I know I will get rained on by all of the 'what if all the GPS satellite fall out of the sky crowd?' If you just want to know where you are, get a backup GPS. I have a Garmin 12 that works just fine after many years. I turn it on about once a month while cruising - sometimes I have to tell it which part of which ocean we are in to help it get started.
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Old 01-19-2012
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Sextants are great for finding your position, Especially when you are far out on the Ocean. When you come in sight of land you transition to coastal piloting.

The nasayers of "archatic" methods of Navigation really don't care or want to invest the time in learning those skills. Now I do enjoy the gps. But in my case I have a C-Plath sextant that I'm comfortable in using. Was using sextants before GPS came into being and never had any confusion as to were I was at on this big blue marble.

Recommend you acquire the best sextant you can afford and learn to use it. But it takes practice, lots of practice in building your skills. Remember that sextants were used for a few centuries before GPS came about.

And there have been many cases where mariners have run aground because they depended on the GPS far to many time.
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Last edited by Boasun; 01-19-2012 at 11:11 PM.
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Old 01-19-2012
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Quote:
Originally Posted by Boasun View Post
Sextants are great for finding your position, Especially when you are far out on the Ocean. When you come in sight of land you transition to coastal piloting.

The nasayers of "archatic" methods of Navigation really don't care or want to invest the time in learning those skills. Now I do enjoy the gps. But in my case I have a C-Plath sextant that I'm comfortable in using. Was using sextants before GPS came into being and never had any confusion as to were I was at on this big blue marble.

Recommend you acquire the best sextant you can afford and learn to use it. But it takes practice, lots of practice in building your skills. Remember that sextants were used for a few centuries before GPS came about.

And there have been many cases where mariners have run aground because they depended on the GPS far to many time.
I can't seem to get it (celestial nav) from fancy book lernin.. can you explain in simple human terms how you do the calculations after shooting the sight (the one thing I can do)?
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Old 01-19-2012
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There are formats that are easy to use. I have Weems & Plath (H.O. 229 Sight solver) that can ease your way into understanding the math involved. And there are a couple of books that simplify Celestrial navigation.
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Old 01-19-2012
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I've only tried two sextants during the past decade, including the Davis plastic sextant sold by West Marine. The best accuracy I experienced was approximately +/- 6 miles, which would be fine in the middle of the ocean. So, if both of my GPS systems failed, and I was well offshore when the failures occurred, then the GPS would be a handy gadget to have onboard. However, I've used Loran-A, Loran-C and GPS, all since their inception, and never experienced a failure. Either I'm darned lucky, or electronic navigation systems are very reliable.

I guess from my perspective, having a good, electronic backup system is a far better investment, especially if you're not going to spend endless days and weeks offshore. However, if you are going offshore, maybe crossing the oceans, then as stated above, purchase the best sextant you can afford--it may end up being your only backup, navigational system.

Good luck on whatever you decide upon,

Gary
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Old 01-19-2012
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::sigh::

Still nothing. What is it with the secret society of celestial..

Thanks anyway... I'll look at what you recommended.
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Old 01-19-2012
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Chris,

If you wish, I can email you a great book on learning how to use a sextant. It's a down to earth book that puts things in plain, easy to understand language. Just email me and I'll send it via return email.

Cheers,

Gary
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Old 01-19-2012
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Quote:
Originally Posted by travlineasy View Post
Chris,

If you wish, I can email you a great book on learning how to use a sextant. It's a down to earth book that puts things in plain, easy to understand language. Just email me and I'll send it via return email.

Cheers,

Gary
I will (and thank you), however I must warn you I have already bought a few books that billed themselves as easy to understand, and I couldn't understand them.. I am terrible at math, math theory, and anything to do with math...

I'll shoot you an email and give it a shot though...
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Old 01-19-2012
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It's on its way.

Good Luck,

Gary
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