Sextant to Learn Navigation Old School

[captmikem]

Here is something I used to use, and I have an NC 77 around someplace as well. They were handy!

[unbusted67]

Very dumb question and a thread highjack. Do you need to have access to unbroken horizon, as if you were at sea, in order to practice sextant use or can you do it on land?

[captmikem]

Originally Posted by unbusted67

Very dumb question and a thread highjack. Do you need to have access to unbroken horizon, as if you were at sea, in order to practice sextant use or can you do it on land?

You can use a pan of water, and superimpose the body on itself, then cut your HS in half if you are on land.
M

[IslandHopper]

Originally Posted by unbusted67

Very dumb question and a thread highjack. Do you need to have access to unbroken horizon, as if you were at sea, in order to practice sextant use or can you do it on land?

There is a few ways of doing it but i found the Practice Bubble Horizon from Celestaire for my Astra IIIB the easiest, it fits other sextants just need to check which.....

https://www.celestaire.com/product/p...ubble-horizon/

[seaunder]

Go to your local United States Power squadron in your area, they can teach you how to use a sextant and probably help you get one you need. if you cant find one answer me as to your location and I will hook you up with the local commander.

Shawn

[Nicholson58]

Originally Posted by doverton

Looking to learn to use a sextant to navigate old school. ( In case of absolute disaster, or just because ) Looking to buy a sextant that is usable, but not the absolute best or most expensive. Amazon has a bunch of possibilities, just not sure what would be good, usable, not expensive, and reasonably accurate.
Anyone have any recommendations?
Thanks Much!

You can acquire the books and sextet on Amazon and EBay. Do your homework and compare with new. Follow also the classifieds on this forum. If there is a boat show near you look for discounts on new ones,

[mqbenedict]

Many on eBay.com

Mark

[369thegoose]

US naval academy up the Hudson River is now teaching the use of sextant to all officers in case of major digital crisis/ crasch since 2 years

[mindful]

I used the book “Starpath, Celestial Navigation, a home study course”, by David Burch. It is excellent and completely comprehensive for teaching you the art. I bought a Frieberger Trommel sextant, a Davis artificial horizon (I live in Indiana), a current year, Nautical Almanac, Publication 249 for your latitude, Universal Plotting Sheets, parallel rulers, a digital watch displaying numbers (vs. hands) and a good pair of nautical dividers. Read the book, work the examples, and it will all come to you! It’s very very satisfying to go out in your back yard, shoot the sun, and then reduce the sight correctly.

[Zzmeyer]

I use an Astra for fun alot on passage. I had a Davis and although it had a fairly large error, the error was the same for all the sites so correction was easy. The Astra's mass makes the measurement more accurate. I use an app, there are several, for quick answers but have developed a spreadsheet for site reductions. The first column is filled in with a previous site to remind me what to do. The right column has references to what book (nautical almanac or HO249) as well as sections. Because I'm not doing site reductions all the time the "cheater" spreadsheet helps me a lot.
http://www.cruisersforum.com/forums/...1&d=1567176155

[sailor1026]

I also recommend the US Power Squadron course. There are two.
Junior Navigator covers sun sights.
Navigator coves sun, moon, planets, and stars.
USPS is working on an on-line version.
I've taken both classes and had previously taken two other classes. The USPS course was by far the best. You do a set of sights and plot them. Jr Navigation is a 5 mile accuracy requirement and Navigation is 3 mile accuracy. They cover the law of cosines calculations and the Nautical Almanac process (in case all electronics are dead). There is a sample cruise that you do as part of each course, which involves reducing sights and plotting positions.
As someone pointed out, you need to do many sights to become competent. Do five to ten sights a day for a couple of weeks. You'll get a feel for what the different corrections are doing if you reduce them on paper.
The Davis sextant is good for learning. Learn how to check and adjust a sextant too. Then drop the big bucks on a metal instrument. I have both. The local Power Squadron will likely have someone who has a metal instrument so you can see and feel the difference. You'll want to use the split mirror and the whole horizon mirror. Check out www.celestaire.com/selecting-a-marine-sextant/

[jimisbell]

Originally Posted by Adelie

I’m gearing up to teach a class. I can send you my notes/syllabus if you want.

I would be interested in those notes.


I am self taught, dont remember where I got the information but no longer have it.


Your notes would help me brush up on the things I have forgotten.


I used to sit in the window of my office on the UT Campus in Austin and take noon sights with my Russian Navy sextant. The Russian sextant is a copy of the Plath and is as good an instrument for much less money. But its not a beginners instrument.

[Rumbero]

Originally Posted by jimisbell

I used to sit in the window of my office on the UT Campus in Austin and take noon sights with my Russian Navy sextant. The Russian sextant is a copy of the Plath and is as good an instrument for much less money. But its not a beginners instrument.

There are a few Russian Navy sextant models; specially one of them, the CHO-T (also know by SNO-T) is a great piece of engineering. I got to know about them and then read further in "The nautical sextant" by W.J. Morris, an expert and real authority in the construction and maintenance of sextants.


Following the provided information (Morris even wrote an specific booklet for the repair and maintenance of the CHO) I fully dismantled and overhauled the sextant, then reassembled and adjusted, and now it works like a charm. I can confirm its precision from positions taken - specially while on land - .
Without doubt an option to consider when looking for a second hand sextant.

[CaptBobR]

I used to own a Coast Guard approved school and taught celestial. I’ve made 6 eastern Trans-Atlantics and 4 western Trans-Atlantics on sailboats and a bunch more on tugboats.
Learn with the cheapest sextant you can find. Start off by using a programmable calculator and an app. First few times go for noon sun sights. You can honestly do that and use Dead Reckoning for a 24 hour day. Get proficient at zeroing the sextant and then move to star sights.
Then after you get good, you can upgrade sextants and start using the Nautical Almanac and Sight Reduction Tables
Feel free to ask questions

[jimisbell]

Originally Posted by Rumbero

There are a few Russian Navy sextant models; specially one of them, the CHO-T (also know by SNO-T) is a great piece of engineering. .

That is the one I have. Came in a very plain grey painted box (typical Russian utilitarian engineering and grey painted sextant. But it is excellent engineering) with most of the tools (missing two screwdrivers and a brush) and two telescopes. 20 years ago for $250. Much higher now.


Remember that the sextant also needs VERY accurate time. Without accurate time the cheapest sextant will do. A radio or a proper nautical clock. The Russian submarine clock is an excelent choice as it was used to launch missiles so is very accurate and parts are still available. it was $39 20 years ago over $200 today.