Two On A Big Ocean The Story of the First Circumnavigation
of the Pacific Basin
in a Small Sailing Ship


      

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SNO-T/CHO-M + Freiberger info

From: Royer, Doug (no email)
Date: Mon Oct 06 2003 - 20:07:39 EDT

  • Next message: George Huxtable: "Re: Checking a sextant calibration."

    Courtney,welcome to the list.Here is what I know.
    I had the opportunity to use both of these types of Russian(I should say
    Soviet)sextants.One was owned by a Polish ABS I served with and he
    consistantly got outstanding LOPs useing his.He won an $1800.00 pool on one
    transit when his final position was less than 0.2nm from the ships GPS pos.
    when the evolution was stopped by the master.
    Both of these sextants types were manufactured I beleive in Riga,Latvia and
    someplace in East Germany between 1947 to 1988.They were built for the
    Soviet Navy to rigorous standards.They are clones taken from the Freiberger
    Prazisionmechanik Co.The optics in the scopes were Zeiss optics.And as all
    Freiberger sextants are of the Drum type.Very good quality machining,
    optics, very dependable and easy to use.The Index mirror is standard size
    about 52 mm and I think also the silvering is on the front face of the
    mirror.You will need to use cal. cylinders,dice or dominoes to check
    perpendicularity of the Index mirror if that is the case.
    The sextants I used were built in the ' 70's or early ' 80's.I can't say if
    there were instrument cal. sheets for these on the lids of the boxes because
    I can't remember.
    All Freiberger sextants(man.after 1975)come with a cert certifying they are
    free of Instument Error for practical purposes as do most sextants
    manufactured today.These Russian sextants are clones of German
    Equipement.Cassens + Plath and Carl Plath sextants have a max. error spec of
    9" of arc over the arc's entire radius.Freiberger is right in there also so
    your Rissian sextant should be the same.I would be more concerned about
    Collumation Error and Index Error than Inst. Error.I wouldn't waste time
    and money trying to have the arc calibrated.I had my MS-733 calibrated years
    ago at a good chunk of change to find the whole error was 11" of arc.If you
    want it collumated there are many places that will do that service for you.
    The Clausen Inst. Co. is the importer for Freiberger sextants in the U.S.
    and I am sure they have a website.If you need an owners manual maybe they
    can help.
    Hope this helps you out and good luck.


  • Next message: George Huxtable: "Re: Checking a sextant calibration."



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