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Old 20-02-2014, 14:24   #16
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Re: simple sextant book?

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I agree that a copy of Bowditch belongs in every navigators library.

And here's how to get your free and legit copy

Maritime Safety Information
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Old 20-02-2014, 15:28   #17
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Re: simple sextant book?

Self-Taught Navigation by Robert Y. Kittredge.
He uses pub 249 and it's a small 80 page book. I used it to "self teach myself" in 1980. It's concise easy reading and will give you the essentials.

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Old 20-02-2014, 15:31   #18
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Re: simple sextant book?

Oh, and Nigel1's link above has a ton of excellent reference books that I've downloaded.

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Old 20-02-2014, 16:13   #19
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Get a copy of Airborne by W F Buckley Jr. It's a good sailing read anyway but provides a simple easy to follow explanation of celestial navigation. He also wrote a book called celestial navigation simplified if you want more detail. Highly recommended.
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Old 20-02-2014, 16:44   #20
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Re: simple sextant book?

Monte,
In my opinion, the best book on Celestial navigation is "Practical Celestial" Navigation" by Susan Howell. It is a simple, straightforward, workshop approach with cumulative exercises. I studied the book a month before sailing season an hour every morning and began taking sights all Summer long. By the end of Summer, I was able to consistently get a fix within 2 NM on sun, moon and star sights. I still use my original Davis Mark 25 plastic sextant 25 years later. Highly recommended. Good luck and good shooting.
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Old 20-02-2014, 16:53   #21
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Re: simple sextant book?

Another vote for 10 Easy Steps to Celestial Navigation, by Kettredge. It tells you what you need, and no esoteric BS to confuse you. I am going to say something that I have said repeatedly on CF. DONT LEARN TO DO A NOON SIGHT. At least not at first. What I found with many cruisers, was that once they had mastered a noon sight, they never bothered to go farther. With only a few steps more you can do normal sun sights and the stars, planets, and moon. I left Mexico doing sun sights, and arrived in the Marquesas doing sun, moon,stars and planets. Kettredge made it easy. Being able to do sun and moon is a great help for someone with less than perfect eyesight, in that for at least a third of the month, you can cross a sun sight with a daytime moon sight for a fix. Also, Venus is much brighter than any star and can be shot in the evening (or morning depending on the time of year) before the horizon gets too dim for older eyesight. Dont underestimate your ability to learn, if the instruction is clear and simple. My 2 cents worth. ______Grant.
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Old 03-04-2014, 18:27   #22
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Re: simple sextant book?

GJordan has a point, yeah, but I take the opposite tack on this. I think it is better to take the baby step and learn to do a LAN (noon sight) first, because it builds confidence to be able to almost immediately do something very useful with your sextant. And if you go no further well then at least you know how to find your latitude at Local Apparent Noon. That's all navigators had, for hundreds of years, and they usually managed. But I would think being able to determine latitude but not get a position, would make most users hungry for more knowledge, and they would at least want to learn how to take a morning or afternoon sight, reduce it to a Line Of Position, and advance or retard it to the noon sight, to get a fix. Just three observations a day of just one body, the Sun, is enough to get you across an ocean.

From that modest beginning, a motivated wannabe navigator would have a fairly easy time of learning to do morning and evening stars. Moon is actually slightly more difficult, believe it or not, if you want accuracy. Just slightly more complicated. Moon and planets should come after stars, for a nice progression.

Not everyone wants to be Bowditch Junior. Some folks are okay with just being able to put a noon position down on the chart every day. Nothing wrong with that, especially if you are also teaching yourself to keep a good DR, which I think is even more important than having a sextant and knowing what to do with it.

I used to insist that any ocean navigator MUST be well practiced and knowledgeable at the art and science of celestial navigation. Redundancy is the sailor's friend. Two or more completely separate means of determining position should be at the top of the checklist for venturing out of sight of land, and between celestial and GPS, its well covered. But I have moderated my stance slightly, in view of the fact that most folks have not only a "real" GPS but also usually a smartphone with a GPS in it, and maybe a USB dongle, too, and multiple means of getting electricity to phone, computer, and free standing GPS. The only weak point in the chain is the GPS system itself. If the North K***ns (don't want to start an international incident) or anyone else shot down or EMP fried all the satellites, then I guess a GPS-only navigator is thoroughly hosed. But otherwise, the study and practice of celestial navigation by the cruising yachtsman is slowly approaching the status of "hobby". It is a beautiful feeling to put a perfect pinwheel fix on a paper chart or plot sheet. The feeling of accomplishment is very gratifying, and there is a major cool factor in using such timeless navigation techniques. But it is less of an essential thing than it was only a few years ago, in the age of the dumb phone, and before you could get a 40 watt solar panel at Harbor Freight for the cost of a nice lunch. So, I submit that skipping over LAN and ex-LAN sun lines in order to ensure comprehensive learning is maybe not the way for the average person to learn. YMMV of course.

Congratulations on your sextant. The Astra is quite a practical and usable instrument, certainly accurate enough if you do your part. The price is nice.

Probably the biggest dealer in Astra sextants in the U.S., Celestaire, also sells books and references, some of which are good choices for a learner text, and some that are just plain interesting and entertaining. I had a book I bought from them (lost dirung Katrina) called "Celestial For The Cruising Navigator", that I rather liked. Taught me a few things, yeah. Not the simplest book, no, but interesting in its approach, which avoids the use of HO229 or HO249 altogether in favor of using an ordinary scientific calculator for sight reduction. This is a good thing to know, certainly. With a solar powered calculator, and memorization of just a couple of formulae, and practice at converting minutes to fractions of a degree, you have a very good failsafe alternative to paper sight reduction tables or dedicated celestial calculators or tables saved to a computer. I don't have a lot of trust in laptop hard drives, me. The vibration, pounding, etc can do bad things to a hard drive platter. And paper tables take up a lot of space, though to be fair most of the time you only need one or at most two volumes to cover the latitudes you will sail in. But knowing those formulas and having a number cruncher is pretty reliable. Anyway I thought I would throw that excellent book in the mix. Wasnt hard to understand, and getting in to the math (no, you don't have to be good at math to do this, just patient and careful) a little, helps you to truly understand how and why it works. Just pulling data from 229 and the almanac and going through a cookbook method works, but doesn't really make you feel anything.

On the subject of almanacs, yes, download. But when you download, you only get the daily pages. There are lots of tables and stuff that you have to get separately. Best to buy an almanac, and when it is out of date at the end of the year, you got hard copy of everything relevant except the daily pages. Download them. What did I say about computers? Oh yeah. They break. So download the whole year so you got it, but also print the daily pages for the duration of your voyage. A hard copy and a computer copy... remember that redundancy thingie? Speaking of which, I do hope that you have a 64GB USB thumb drive for backing up stuff. They are pretty much immune to normal shock and vibration, a great place to keep an extra copy of programs, waypoints, daily pages, digital charts, etc.

Google is your friend. Here is a little tidbit of knowledge for you.
CELESTIAL REASONING: Quick & Dirty Noon Sights

So maybe you don't even need a book?

http://www.davisnet.com/product_docu...0_IM_00011.PDF
Longitude by chronometer - Wikipedia, the free encyclopedia
Astro Navigation: All you need to navigate by the Sun; Almanac, Sight Reduction Tables.

A couple more. Just to illustrate the treasure of knowledge you can find online. Never mind the youtube videos.

Anyway welcome to the dark side. And HAVE FUN with your sextant. Yeah navigation is serious business but it can be lots of fun too.
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Old 03-04-2014, 18:34   #23
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Re: simple sextant book?

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Originally Posted by onestepcsy37 View Post
correction. that 'eternal table' was for the sun and made it unnecessary to buy a new nautical almanac every year. it also had tables to allow you to reduce your own sight without h.o. 249 or h.o. 214, but it was somewhat complicated to use. with a modern scientific calculator it would have been easier.
I believe there is an APP for the reduction tables. (assumes your hand-held electronic toy has power.)
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Old 03-04-2014, 18:42   #24
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Re: simple sextant book?

Its great to hear someone is actually interested in using a sextant for something other than a conversation piece. The best books have all been mentioned I would suggest that you purchase a false horizon and practice a bit on dry land when you start trying to take a sight on a boat that moving around its a whole different ball game using the false horizon will help you get a feel how to hold the sextant and how to rock it to get the sight right plotting a sight by celestial bodies is very satisfying Its sad that us Merchant marine officers are the only ones required to know it anymore they did away with it at the US Naval Academy years ago.

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Old 03-04-2014, 20:06   #25
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Re: simple sextant book?

Nancy Blewitt's book is the best. Also, William F. Buckley does a good job of explaining the basics in "Airbourne"

There are a lot of good resources and links on this FB page:
https://www.facebook.com/pages/The-C...25602470905965
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Old 04-04-2014, 04:53   #26
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Re: simple sextant book?

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Nancy Blewitt's book is the best. Also, William F. Buckley does a good job of explaining the basics in "Airbourne"

There are a lot of good resources and links on this FB page:
https://www.facebook.com/pages/The-C...25602470905965
Sorry, that should be Mary Blewitt: Celestial Navigation for Yachtsmen. No nonsense, easy to follow. Very slim volume (as it should be).
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Old 07-06-2014, 13:27   #27
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Re: simple sextant book?

Tom Cunliffe's book Celestial Navigation is about as short as you can get I think. I have read it a number of times--takes a while to absorb for me--he does a great job of explaining and encouraging.

You can download a copy of Bowditch at http://msi.nga.mil/NGAPortal/MSI.portal?_nfpb=true&_pageLabel=msi_portal_page_6 2&pubCode=0002

Celestial Navigation for Yachtsmen by Mary Blewitt is supposed to be good. http://www.amazon.ca/Celestial-Navigation-Yachtsmen-Mary-Blewitt/dp/0070059284

Teacup Navigation http://www.teacupnavigation.net/ is an excellent resource with lots of info.

All the best, MarkH
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Old 07-06-2014, 17:12   #28
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Re: simple sextant book?

I studied HO 229 and used HO 211. I'm finding it difficult to find the sight reduction forms which made it easier to work the sights. I'm not sure about any tables that go out of date, but according to Hewitt Schlereth HO 211 is valid as long as spherical trigonometry remains valid.
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Old 08-06-2014, 01:04   #29
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Re: simple sextant book?

Generoll: Is there anything here you could use?? Navigation Worksheets
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Old 08-06-2014, 05:45   #30
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Re: simple sextant book?

Thanks Sunbear:

The form is useful, but so far I haven't found the specific form I used for 211 when I last did this about 30 years ago.

HO 211 uses DR position, LHA, and Dec as arguments and simply requires adding or subtracting to arrive at Hc from which you get your LOP. Having a form which puts everything in order makes the process much simpler.

I think the new(er) S tables may be a variation or improvement on Ageton and I'm going to try and find some worksheets for those tables as well.

Gene
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