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Go Back   SailNet Community > Skills and Seamanship > Seamanship & Navigation
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Seamanship & Navigation Forum devoted to seamanship and navigation topics, including paper and electronic charting tools.


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  #11  
Old 03-17-2004
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p424107 is on a distinguished road
ATTN: Celestial Navigators

I am looking for a tamaya sextant. If anyone has one for sale please email me.
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  #12  
Old 08-31-2004
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ATTN: Celestial Navigators

Imagine this.a 26 foot sloop going back to cali from hawaii.I used a WW2 navy surplus David White sextant.The horizon mirror was about the size of a postage stamp.a german sextant from the same era had a mirror about the size of a silver dollar coin.Any way the mirror in question began to corrode,I had no spares.I could see the horizon through the un silvered part,and only the moon and sun through the remaining silvered portion.so I held the sextant upside down,brought the horizon up to polaris,yes,I swung it upside down( get the picture?)and came up with what I figuered had to be accurate to within one degree,of about 46 degrees.A z=90 later on the moon gave me longitude of about 145 west.and thats where I turned east.eleven days later I was home
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  #13  
Old 09-11-2004
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seadoodude is on a distinguished road
ATTN: Celestial Navigators

My father recieved a Tamaya #63432 sextant and he asked me to find information on it. It is very old. Can you advise me, or send me information on this unit please?
Thank you,
Jerry
seadoodude2002@juno.com
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  #14  
Old 11-27-2004
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ATTN: Celestial Navigators

actually the best characteristic of any metal sextant over a plastic one reguardless of full or half mirror,or any other type of optics is the index error.a metal sextant of any quality after normalizing in the weather will have an error of +/- .5 degrees which plots to less than 1/2 mile on a vpos plotting sheet.a plastic sextant,no matter what kind of high quality optics,or fancy wooden box,may have an index error of 20 or 30 degrees,and the instability of the plastic body constantly changes in the weather.When set to zero the image will split right before your very eyes.I keep an old plastic davis in its plastic box securely sealed with tape, my primary sextant of choice is the astra 3b.It should also be noted here that celestial navigation is based completely on a false theory called the geocentric universe theory.that implies the earth is the center of the universe and everything revolves around it .also it is in no way an exacting science.the angles measured can be slightly different between using either the left or right eye.then theres the mathematics .theres a well documented case where a vessel went on a reef because they used the wrong formula for being on the other side of the international date line.it had something to do with assumed longitude adding up to zero instead of subracting to zero.actually my first and most immediate weapon of choice is a garmin 12 but thats cheating
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  #15  
Old 11-28-2004
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ATTN: Celestial Navigators

Starcresttoo:
If what you wrote is even remotely true (which it''s not) then it is astonoshing to know just how many navigators of old were able to get to their planned destinations - without error.

Long ago, it may have been based on the geocentric theory, but not since the acceptance of Capernicus'' heliocentric theory.

I too have a metal sextant (from the Russian Navy) and it is fairly accurate. On a clear day or night and in calm seas, I can get to within a half mile of my true location - as indicated by my Garmin 76S.

~ Happy sails to you ~ _/) ~
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  #16  
Old 11-28-2004
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ATTN: Celestial Navigators

what I have written is based upon what I have been told to me by instructors of this dying art,and is also based upon more than 15000 miles of mostly single handed sailing across the pacific on 5 different voyages,on small craft less than 30 feet,in the most extreme conditions,in the days before gps was even a term .Even to this day we still dont know exactly where coulmbus set foot, I will bet even they didnt know exactly where they were either and I am sure there were many navigators of old that never made it to their destinations.
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Old 11-28-2004
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ATTN: Celestial Navigators

But suprizingly many old navigators DID make it to their intended destinations. Many of those who didn''t used faulty maps (as is the case for C. Columbus) or none at all. :^(

With decent maps and a good sextant, you and countelss others have made it across vast oceans - long before GPS was invented.

Take heart, if the GPS system ever fails, you and others who know how to use a sextant can still find your way to within a mile or so.

~ Happy sails to you ~ _/) ~
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  #18  
Old 11-28-2004
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ATTN: Celestial Navigators

better yet I will keep a second or maybe 3rd brand new still in the wrapper spare gps units .why not they are so inexpensive.on my last trip back from hawaii I actually did have a loran c fail on me.the #2 button wouldnt work.I had to play with it for a while then I kept it on constantly.It was also some what variable in its readouts,as it gave inconsistant readouts between day and nite.so I actually used my sextant to double check it.that north star is very accurate
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Old 02-08-2005
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ATTN: Celestial Navigators

I once read (forgot which book it was in) that the data in the Nautical Almanacs repeats itself every four years so that one only needs any four consecutive years to be covered indefineteley. Anyone know if this is true? Or perhaps if it true just for certain celetial objects (Moon and Sun.)

Thanks,
R.
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  #20  
Old 02-27-2005
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ATTN: Celestial Navigators

its not true,especially for planets. the word planet means "wander"and they ar never in the same place twice
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