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post #11 of 69 Old 01-04-2016
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re: Sextant and finding out where you aren't

A post from another thread that seems appropriate

Quote:
It is time to rediscover the joys of celestial navigation, not merely as a safety net, but because using a sextant to find our way puts us in the closest possible touch with the natural world at its most sublime.
Sextant: A Voyage Guided by the Stars and the Men Who Mapped the World's Oceans by David Barrie.
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post #12 of 69 Old 01-04-2016
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re: Sextant and finding out where you aren't

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Originally Posted by Vasco View Post
Maybe the correct spelling might be a start. Sorry, couldn't resist.
Maybe you are mistaken, I would be interested in learnig more about a sextent!!!!!!!!!!!!!

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post #13 of 69 Old 01-04-2016
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re: Sextant and finding out where you aren't

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The app I have uses the North star, which did not help in my South Atlantic crossing
Bunch of programmers unaware of the Southern Cross perhaps.

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post #14 of 69 Old 01-04-2016 Thread Starter
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re: Sextant and finding out where you aren't

My son has an app on his phone which identifies stars when you point it at them, its quite cool. You might have to get an Australian app if you want to find the Southern Cross.
Shpelling is not my forte.
The world may have moved on, I still find the old ways interesting, be it a hand lead with tallow to check the bottom, a hand bearing compass, a walker log. or a sextant. The techniques of Polynesians, Vikings and other ancient mariners are of interest.
local knowledge and pilotage.
Doubling the angle on the bow was part of the CYA basic Nav. when I did it a couple of decades ago, I can't remember if distance by vertical angle was or not. a running fix was. I don't think a horizontal sextant angle was. I certainly used them all at one time or other. though not often. I used mine for celestial much more than terrestrial nav
I don't know If the modern Yachtmaster includes these or not.
Just figured I found it interesting, and thought a few others might also.
A few hundred years from now, navigation may be more about astro physics and theoretical mathematics involving Einstein's theory of relativity. Or he might be wrong. The true navigators of the day who are worth their salt will still be interested in how ancient mariners did it.
They may also be interested in a sextent.
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Last edited by Uricanejack; 01-04-2016 at 07:42 PM.
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post #15 of 69 Old 01-04-2016
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re: Sextant and finding out where you aren't

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Originally Posted by Uricanejack View Post
I don't If the modern Yachtmaster includes these or not.
To get my ISPA Yachtmaster Ocean I had to show that I could do noon sights and sun-run-sun sights, just in case. I did those on the South Atlantic crossing. Being in the Southern Hemisphere with the sun almost overhead at times and crossing the prime meridian made life interesting.

For my own interests, I am going to brush up on my star, planet, and moon shots.

I am giving some serious consideration to re-doing my CYA / Sail Canada celestial exam and maybe get my Sail Canada Offshore Instructors ticket to go along with my ISPA ticket. They still insist on a full celestial nav course. I know there is interest in celestial courses in Calgary.

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re: Sextant and finding out where you aren't

I kind of figured the offshore yachtmaster included celestial nav and the sextant. Capta mentioned the use of vertical angles and horizontal angles by sextant for coastal nav. Useful techniques on occasion. just wondering if it was part of the basic or coastal yachtmaster course.

Stars can be done much the same as the sun, with the advantage of having more than one. at one time I did them long hand using logarithms. The same as I did with the sun. I moved on to a pocket calculator for the sun or the occasional planet. I found the air nav tables for stars quite handy and faster the calculator. The moon I did because I had to. in practice I found it to be a PITA. to many corrections, its to close and the errors to many.
The big advantage of the air tables for selected stars, was the selection of the best ones, sometimes I would use them to just pick my stars, then run three through the calculator or pocket computer (16K casio)(long dead) computers have exceeded my basic knowledge now. I would need an app.
I also used to use a star finder.
I know you can down load the American almanac for free, I think they do the star tables as well.

It's been a long time since I've crossed the prime meridian, the international date line or the equatorial regions. So I would have to scratch my head and puzzle a bit myself. When heading south on the right day I used to like to get a simultaneous observation of the sun. you had to be quick to get it to work.

Last edited by Uricanejack; 01-04-2016 at 07:57 PM.
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post #17 of 69 Old 01-05-2016
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re: Sextant and finding out where you aren't

I lack only the sextant, the knowledge and the time to learn it all.

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1974 C&C27 MkII

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post #18 of 69 Old 01-05-2016
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re: Sextant and finding out where you aren't

My sister visited here in Thailand and commented on how the setting crescent moon looks different. That led to a disscusion about being on a round ball and not at 49th parallel. That led to comments about the moon's orbit not being earth equatorial. A plumb bob and protractor across the moons arms give a latitude(sort of) Good enough for beach bound and kinda fun as an exercise in wrapping your head around the celestial.(without looking it up ,moon cycle about 18.6 years ,inclination max 5.09 ,earth,max 23.2 So the angle of the dangle was really noticable when I was in the arctic and the moon came up over the ice to the north. impressive.
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post #19 of 69 Old 01-05-2016
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re: Sextant and finding out where you aren't

Went to sea in the days when a sextant was all you had for determining your position. And no using H.O.214, that was considered cheating. Sextant, Nautical Almanac and Norie's Nautical Tables. You had to learn the principles of navigation. Had to learn spherical trigonometry and math certainly was not my forte. I don't miss those days, sold my sextant a long time ago and my sight book is in a canvas covered box in my basement, gathering dust. The vast majority of sailors nowadays do not own a sextant. Doubt if they would let you board a plane with one yet in the "good old days" that was part of your carry-on luggage when flying to board your next ship or going home on leave, a sextant in a mahogany box.

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Toronto in summer, Bahamas in winter.

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post #20 of 69 Old 01-05-2016
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re: Sextant and finding out where you aren't

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Originally Posted by Vasco View Post
Doubt if they would let you board a plane with one yet in the "good old days" that was part of your carry-on luggage when flying to board your next ship or going home on leave, a sextant in a mahogany box.
What prevents a sextant as carry on?

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