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Re: C.Plath on Ebay

From: Courtney Thomas (no email)
Date: Mon Jun 13 2005 - 10:07:49 EDT

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    Thanks Alex. I look forward to it.
    Courtney

    On Mon, 2005-06-13 at 04:13, Alexandre Eremenko wrote:
    > Cortney,
    > I qm traveling now
    > (without my sextant). Will come back
    > on June 28 and tell you the adjusting procedure.
    > Alex.
    >
    > On Fri, 10 Jun 2005, Courtney Thomas wrote:
    >
    > > Assuming the inverting scope of the -SNO-M to be like the SNO-T:
    > >
    > > Would the 8 screws on the barrel mount bracket, nearer the end opposite
    > > the eyepiece...be the collimation adjustment on the SNO-M ?
    > >
    > > Or only 4 of them ? If yes, which 4, the most or least, forward ?
    > >
    > > If yes, do you know the proper adjustment sequence ?
    > >
    > > Thanks again,
    > >
    > > Courtney
    > >
    > >
    > > On Fri, 2005-06-10 at 15:01, Alexandre Eremenko wrote:
    > > > In Russian sextants, collimation adjustment is
    > > > not a feature of the sextant, but a feature of the scope.
    > > > I have never seen an SNO-M in real life, but from the pictures
    > > > I conclude that they come with two kinds of scopes.
    > > > (Like SNO-T). It is the UNIQUE Russian INVERTING SCOPE
    > > > which has the collimation adjustment.
    > > > I have not seen ANY other scope like that, and I wonder why
    > > > all Call Nav books still mention this adjustment
    > > > (which cannot be made on anything but this Russian inverting scope).
    > > >
    > > > All kinds of Russian sextants and scopes that I know can be seen in
    > > > http://www.maurnavy.com/index.html
    > > > Picture 2 shows an SNO-M with inverting scope (which has collimation
    > > > adjustment).
    > > > Picture 1 shows an SNO-T but with ordinary (straight) scope.
    > > > (New SNO-T come with two scopes: ordinary and inverting)
    > > > Picture 4 shows some old sextant resembling SNO-M with
    > > > some old scope (possibly inverting)
    > > > which also has the collimation adjustment,
    > > > but this is not the modern inverting scope.
    > > >
    > > >
    > > > On Fri, 10 Jun 2005, Courtney Thomas wrote:
    > > >
    > > > > Then the SNO-M does not have the collimation error adjustment ?
    > > > >
    > > > > Thank you,
    > > > > C.Thomas
    > > > >
    > > > >
    > > > > On Fri, 2005-06-10 at 02:05, Alexandre Eremenko wrote:
    > > > > > Yes, of course.
    > > > > > This picture could be used in a beginner's
    > > > > > textbook to explain what is "collimation error":-)
    > > > > > Modern sextant scopes (for the reasons that excape me)
    > > > > > do not have collimation error adjustment,
    > > > > > with one exception: the inverting scope of SNO-T.
    > > > > > Once Bill suggested to adjust collimation error
    > > > > > with a hammer...
    > > > > >
    > > > > > This is apparently what the owner of this sextant did,
    > > > > > and after he failed, he sells the sextant:-)
    > > > > >
    > > > > > Alex.
    > > > > >
    > > > > > On Thu, 9 Jun 2005, Robert Eno wrote:
    > > > > >
    > > > > > > Have a look at this sextant on e-bay.
    > > > > > >
    > > > > > > Are my eyes deceiving me or is the rising piece on the scope bent out of shape?
    > > > > > >
    > > > > > > http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&category=37971&item=7328115519&rd=1
    > > > > > >
    > > > >
    > >


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